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[database] Support multiple (non-best) chains, concurrent reads on different forks. #255

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davecgh opened this issue Jan 27, 2015 · 6 comments · Fixed by #380
Closed

[database] Support multiple (non-best) chains, concurrent reads on different forks. #255

davecgh opened this issue Jan 27, 2015 · 6 comments · Fixed by #380

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@davecgh
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davecgh commented Jan 27, 2015

Issue by jrick
Thursday Jul 17, 2014 at 04:34 GMT
Originally opened as btcsuite/btcdb#6


The database currently only saves the best chain. If a fork extends beyond the current best chain, the reorged blocks will be removed from the database. This makes the database unsafe for multiple callers who concurrently expect their given block range to be valid.

For example, when btcd must rescan some range of blocks, and the tip of the range is removed from the best chain due to a new best block, db lookups will begin failing for missing the block for some hash, or worse (if only heights are used), lookups will silently continue with no indication that previously processed blocks may not be on the same fork.

A better solution would be to use an iterator which allows walking through some range of blocks in a fork. Even if the best chain is switched, these blocks can still be iterated over. After the iteration is finished, the caller can finish (it returned results about the chain at the time the request was made) or a switch back to the main chain and/or best block can be made if more blocks were attached.

@davecgh
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davecgh commented Jan 27, 2015

Comment by jongillham
Friday Sep 19, 2014 at 11:28 GMT


I don't fully understand the issue here but would it mean that Db.DropAfterBlockBySha(*btcwire.ShaHash) (err error) would no longer be needed? If so, it would have massive positive implications for a whole host of NoSQL key/value stores that are currently unable to meet the transactional requirements of DropAfterBlockBySha.

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davecgh commented Jan 27, 2015

Comment by davecgh
Friday Sep 19, 2014 at 13:56 GMT


In short, the ask here is for the database to support storage of orphan blocks/side chains. Currently, it only ever stores blocks which are on the main chain. Changing this will require a pretty significant amount of changes in other packages because they all work off the documented assumption that asking the database for blocks and transactions are only available if they have already been fully validated and are in the current best (main) chain.

The description here is extremely misleading because it's referring to btcd when it should be referring to RPC.
The database has a lock which prevent reorgs out from under callers in btcd itself, so the assertion that "this makes the database unsafe for multiple callers who concurrently expect their given block range to be valid" is not accurate for btcd. What this is referring to is RPC, which is always a snapshot of the current state. In that case, the statement is correct.

That said, we're ultimately going to want to allow storage of the side chain blocks as it will allow a few more advanced techniques to be used for optimizations and allow RPC access to information about reorged chains which is really what this issue is asking for.

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davecgh commented Jan 27, 2015

Comment by jongillham
Friday Sep 19, 2014 at 14:29 GMT


Ok thanks for the explanation I understand now.

I completely agree that storing side chains is a good aim. Being able to detect and monitor side chains as they develop on the Bitcoin network also has potential security benefits for clients of btcd who want to limit their exposure to chain reorgs.

A consequence of storing side chains might make it possible for the btcdb.Db interface to be completely non-destructive to blocks and transactions. It would therefore make it much easier/possible to implement btcdb.Db drivers for the NoSQL databases that have limited transaction support.

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davecgh commented Jan 27, 2015

Comment by davecgh
Tuesday Dec 23, 2014 at 03:21 GMT


As an update to this, the current plan is to start tackling this within the next few weeks. We have been discussing several of the design implications and the current plan is as follows:

The btcdb interface is going to change quite significantly. The current interface and approach has a few undesirable properties such as the following:

  • The problem this issue discusses
  • The current interface is based on a fairly specific interface for block storage with an assumed high level of intelligence built-in to each backend driver.
  • This leads to all back-end implementations (ldb and memdb, currently) needing to repeat a lot of logic that is non-trivial to get right and really should only be done once at a higher layer
    • As a concrete example, adding new functionality, such as the optional address index work being done by @Roasbeef, currently has to be implemented in each backend driver.

To resolve the above issues (and others not covered), the current plan is to redesign the interface so it provides better scalability, more easily facilitates new backends such as BigTables for GAE, and opens the door for supporting more advanced features such as block pruning. To accomplish this, the idea is to have the new interface provide two major categories as follows:

  • Atomic operations for metadata such as the the block and transaction location metadata, the utxo set, and an optional address index.
    • The interface for this functionality is currently planned to be very similar to the recently added walletdb interface.
  • Raw block storage
    • Since the metadata and block data will ultimately not necessarily live in the same place, the interface for raw block storage needs to be separate from the metadata storage mechanism in the previous point
    • This will NOT contain additional logic to ensure the block connects to an existing one or track spends like the current interface

Finally, these changes mean that most of the current Bitcoin-specific intelligence, like spend tracking, ensuring the block being inserted extends the main chain, and unspending transactions when blocks are dropped, will no longer live in btcdb and instead will be moved to a higher layer where they belong.

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davecgh commented Jan 27, 2015

Comment by Roasbeef
Tuesday Dec 23, 2014 at 06:22 GMT


Overall, I'm very pleased with @davecgh's proposed changes to btcdb. We've been discussing/brainstorming the potential API changes via IRC over the past fews days as I've started work on adding the optional address index to btcd.

Some of the design flaws/quirks with the current interface have been made rather apparent as I've been taking a more critical look at btcdb's codebase in order to add the new functionality along with complete test coverage.

IMO the new separation of concerns (metadata vs blocks) that the proposed changes would bring about are much needed. The old interface appears to have been designed primarily with LevelDB in mind, as well as storage of metadata and blocks stuffed into the same location (which forces all drivers to have DropAfterBlockBySha implemented). btcchain would also need to be altered behavior wise to use the new interface. Having a set of core, atomic operations for implementing metadata related functionality (indexes, spend data, etc.) will make such features much easier to add in the future. Additionally, it should also allow various drivers a higher degree of freedom implementation wise. As of now, adding a new btcdb feature entails adding a new general, opaque function to the db interface, tightly coupling the various database drivers together. As @davecgh said, this process results in unnecessary duplication when targeting new features for a specific driver.

I look forward toward to the ultimate interface re-write whatever shape it may take. A more flexible interface a may attract new contributors seeking to add alternative databases for btcd's backend store.

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davecgh commented Jan 27, 2015

Comment by jongillham
Monday Dec 29, 2014 at 04:35 GMT


It was great to read @davecgh's btcdb proposal above. I think it's the right direction to go and I have found that this separation of concerns can work well with NoSQL datastores.

Here's the type of architecture that, from my experience, is compatible with concurrent block chain reads and NoSQL datastores:

type Db interface {
    FetchBlockByHash(blockHash *btcwire.ShaHash) (*btcutil.Block, error)
    FetchTxByHash(txHash *btcwire.ShaHash) (*btcwire.MsgTx, error)

    // There can be more than one block at a certain height.
    FetchBlocksByHeight(height int64) ([]*btcutil.Block, error)

    FetchHeighestBlocks() ([]*btcutil.Block, error)

    // A transaction can be in more than one block if a side branch contains 
    // it as well as the main branch.
    FetchTxBlocks(txHash *btcwire.ShaHash) ([]*btcutil.Block, error)

    // Returns a list of transaction hashes that reference txOut with their inputs.
    // Note that the presence of side branches means that TxOut can be
    // referenced in more than one transaction.
    FetchTxOutReferences(txOut *btcwire.TxOut) ([]*btcwire.ShaHash, error)

    InsertBlock(block *btcutil.Block) error
}

There are a couple of points to make with the above interface:

  1. It embraces the fact that if we store side branches then multiple blocks can exist at the same height, one transaction can be in multiple blocks and one TxOut can be in multiple transactions.
  2. InsertBlock needs to do an awful lot of work however it does not need to be done atomically and can be done in a roll forward idempotent way. This is especially important when considering NoSQL datastores where table locking is not an option. The following is the work InsertBlock needs to do and the order it could be done:
    1. Insert each transaction into a tx hash index.
    2. Iterate through all the new TxOuts for each block transaction and add them to a TxOut index.
    3. Iterate through all the new TxIns and update previous TxOuts with a reference for FetchTxOutReferences.
    4. Insert the block into a block hash index.
    5. Insert the block into a height index.

The following is the functionality that should be calculated at a higher level by something like btcchain and not be pre calculated or stored in the datastore:

BestTip() (*btcutil.Block, error)
IsMainBranch(blockHash *btcwire.ShaHash) (bool, error)
IsUnspent(txOut *btcwire.TxOut) (bool, error)

BestTip() is calculated by iterating through the block chain and using the rules already in btcchain to select a winning block if there are two competing blocks at the same height.
IsMainBranch() returns true for blockHash if it is the only block at that height. Otherwise it must iterate up the chain until it determines if blockHash is on the longest branch. If we reach the tip of the block chain then BestTip() can be used if multiple blocks are still competing.
IsUnspent is calculated by calling Db.FetchTxOutReferences() for the specified TxOut and iterating through each referenced transaction to see if any of them are on a block on the main branch. If any are then the TxOut is considered spent.

Judicious use of caching for the above three functions could be possible so long as the cache is wiped as soon as InsertBlock updates the block height index.

Anyway, I am not sure this solution exactly addresses @davecgh's proposal however I am looking forward to see how it all evolves.

@davecgh davecgh changed the title Support multiple (non-best) chains, concurrent reads on different forks. [database] Support multiple (non-best) chains, concurrent reads on different forks. Jan 27, 2015
davecgh added a commit to davecgh/btcd that referenced this issue Apr 16, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary of some of the reasons for the major redesign are as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intellegience such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.
- The vast majority of database activity after the initial block download
  is read activity, however leveldb, as its name implies, is optimized for
  levelled write performance as opposed to read performance.  This is
  really the exact opposite of the desired characteristics for a bitcoin
  database.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich meatdata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of differente mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffboltdb (flat file plus boltdb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- The metadata storage uses boltdb under the hood which provides fast
  memory-mapped access
  - NOTE: Due to the fact the database can get quite large and due to how
    the OS does memory-mapped files this can result in the process showing
    huge amount of memory used.  This is typical for memory-mapped files,
    but the key thing to remember is the reported memory is not _really_
    used because the OS will relinquish it as soon as other processes need
    it
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Apr 16, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary of some of the reasons for the major redesign are as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intellegience such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.
- The vast majority of database activity after the initial block download
  is read activity, however leveldb, as its name implies, is optimized for
  leveled write performance as opposed to read performance.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffboltdb (flat file plus boltdb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- The metadata storage uses boltdb under the hood which provides fast
  memory-mapped access
  - NOTE: Due to the fact the database can get quite large and due to how
    the OS does memory-mapped files this can result in the process showing
    huge amount of memory used.  This is typical for memory-mapped files,
    but the key thing to remember is the reported memory is not _really_
    used because the OS will relinquish it as soon as other processes need
    it
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Apr 16, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary of some of the reasons for the major redesign are as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intellegience such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.
- The vast majority of database activity after the initial block download
  is read activity, however leveldb, as its name implies, is optimized for
  leveled write performance as opposed to read performance.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffboltdb (flat file plus boltdb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- The metadata storage uses boltdb under the hood which provides fast
  memory-mapped access
  - NOTE: Due to the fact the database can get quite large and due to how
    the OS does memory-mapped files this can result in the process showing
    huge amount of memory used.  This is typical for memory-mapped files,
    but the key thing to remember is the reported memory is not _really_
    used because the OS will relinquish it as soon as other processes need
    it
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Apr 17, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.
- The vast majority of database activity after the initial block download
  is read activity, however leveldb, as its name implies, is optimized for
  leveled write performance at the expense of read performance.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffboltdb (flat file plus boltdb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- The metadata storage uses boltdb under the hood which provides fast
  memory-mapped access
  - NOTE: Due to the fact the database can get quite large and due to how
    the OS does memory-mapped files this can result in the process showing
    a huge amount of memory used.  This is typical for memory-mapped
    files, but the key thing to remember is the reported memory is not
    really used because the OS will relinquish it as soon as other
    processes need it
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Apr 17, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.
- The vast majority of database activity after the initial block download
  is read activity, however leveldb, as its name implies, is optimized for
  leveled write performance at the expense of read performance.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffboltdb (flat file plus boltdb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- The metadata storage uses boltdb under the hood which provides fast
  memory-mapped access
  - NOTE: Due to the fact the database can get quite large and due to how
    the OS does memory-mapped files this can result in the process showing
    a huge amount of memory used.  This is typical for memory-mapped
    files, but the key thing to remember is the reported memory is not
    really used because the OS will relinquish it as soon as other
    processes need it
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Apr 30, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.
- The vast majority of database activity after the initial block download
  is read activity, however leveldb, as its name implies, is optimized for
  leveled write performance at the expense of read performance.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffboltdb (flat file plus boltdb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- The metadata storage uses boltdb under the hood which provides fast
  memory-mapped access
  - NOTE: Due to the fact the database can get quite large and due to how
    the OS does memory-mapped files this can result in the process showing
    a huge amount of memory used.  This is typical for memory-mapped
    files, but the key thing to remember is the reported memory is not
    really used because the OS will relinquish it as soon as other
    processes need it
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue May 1, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.
- The vast majority of database activity after the initial block download
  is read activity, however leveldb, as its name implies, is optimized for
  leveled write performance at the expense of read performance.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffboltdb (flat file plus boltdb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- The metadata storage uses boltdb under the hood which provides fast
  memory-mapped access
  - NOTE: Due to the fact the database can get quite large and due to how
    the OS does memory-mapped files this can result in the process showing
    a huge amount of memory used.  This is typical for memory-mapped
    files, but the key thing to remember is the reported memory is not
    really used because the OS will relinquish it as soon as other
    processes need it
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Jul 7, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.
- The vast majority of database activity after the initial block download
  is read activity, however leveldb, as its name implies, is optimized for
  leveled write performance at the expense of read performance.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffboltdb (flat file plus boltdb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- The metadata storage uses boltdb under the hood which provides fast
  memory-mapped access
  - NOTE: Due to the fact the database can get quite large and due to how
    the OS does memory-mapped files this can result in the process showing
    a huge amount of memory used.  This is typical for memory-mapped
    files, but the key thing to remember is the reported memory is not
    really used because the OS will relinquish it as soon as other
    processes need it
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Jul 17, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Jul 17, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Jul 17, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Jul 17, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Jul 17, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Jul 28, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Jul 28, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Jul 28, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Jul 28, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Aug 26, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Aug 26, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Sep 6, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Sep 17, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Oct 16, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Oct 16, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Oct 16, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Oct 16, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Oct 23, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Oct 24, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Oct 26, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Nov 14, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Nov 28, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Dec 8, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Dec 10, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Dec 29, 2015
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Jan 6, 2016
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Feb 1, 2016
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Feb 1, 2016
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Feb 3, 2016
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
davecgh added a commit to davecgh/btcd that referenced this issue Mar 16, 2016
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.
davecgh added a commit to davecgh/btcd that referenced this issue Mar 16, 2016
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.
TheSusort pushed a commit to qchain/btcd that referenced this issue May 17, 2016
This commit contains a complete redesign and rewrite of the database
package that approaches things in a vastly different manner than the
previous version.  This is the first part of several stages that will be
needed to ultimately make use of this new package.

Some of the reason for this were discussed in btcsuite#255, however a quick
summary is as follows:

- The previous database could only contain blocks on the main chain and
  reorgs required deleting the blocks from the database.  This made it
  impossible to store orphans and could make external RPC calls for
  information about blocks during the middle of a reorg fail.
- The previous database interface forced a high level of bitcoin-specific
  intelligence such as spend tracking into each backend driver.
- The aforementioned point led to making it difficult to implement new
  backend drivers due to the need to repeat a lot of non-trivial logic
  which is better handled at a higher layer, such as the blockchain
  package.
- The old database stored all blocks in leveldb.  This made it extremely
  inefficient to do things such as lookup headers and individual
  transactions since the entire block had to be loaded from leveldb (which
  entails it doing data copies) to get access.

In order to address all of these concerns, and others not mentioned, the
database interface has been redesigned as follows:

- Two main categories of functionality are provided: block storage and
  metadata storage
- All block storage and metadata storage are done via read-only and
  read-write MVCC transactions with both manual and managed modes
  - Support for multiple concurrent readers and a single writer
  - Readers use a snapshot and therefore are not blocked by the writer
- Some key properties of the block storage and retrieval API:
  - It is generic and does NOT contain additional bitcoin logic such spend
    tracking and block linking
  - Provides access to the raw serialized bytes so deserialization is not
    forced for callers that don't need it
  - Support for fetching headers via independent functions which allows
    implementations to provide significant optimizations
  - Ability to efficiently retrieve arbitrary regions of blocks
    (transactions, scripts, etc)
- A rich metadata storage API is provided:
  - Key/value with arbitrary data
  - Support for buckets and nested buckets
  - Bucket iteration through a couple of different mechanisms
  - Cursors for efficient and direct key seeking
- Supports registration of backend database implementations
- Comprehensive test coverage
- Provides strong documentation with example usage

This commit also contains an implementation of the previously discussed
interface named ffldb (flat file plus leveldb metadata backend).  Here
is a quick overview:

- Highly optimized for read performance with consistent write performance
  regardless of database size
- All blocks are stored in flat files on the file system
- Bulk block region fetching is optimized to perform linear reads which
  improves performance on spindle disks
- Anti-corruption mechanisms:
  - Flat files contain full block checksums to quickly an easily detect
    database corruption without needing to do expensive merkle root
    calculations
  - Metadata checksums
  - Open reconciliation
- Extensive test coverage:
  - Comprehensive blackbox interface testing
  - Whitebox testing which uses intimate knowledge to exercise uncommon
    failure paths such as deleting files out from under the database
  - Corruption tests (replacing random data in the files)

In addition, this commit also contains a new tool under the new database
directory named dbtool which provides a few basic commands for testing the
database.  It is designed around commands, so it could be useful to expand
on in the future.

Finally, this commit addresses the following issues:

- Adds support for and therefore closes btcsuite#255
- Fixes btcsuite#199
- Fixes btcsuite#201
- Implements and closes btcsuite#256
- Obsoletes and closes btcsuite#257
- Closes btcsuite#247 once the required chain and btcd modifications are in place
  to make use of this new code
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