docs: add an overview of the creation and querying of snapshots #5270
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
joshieDo
added
C-docs
mattsse
requested changes
Nov 2, 2023
Comment on lines
+71
to
+73
| [`Snapshotter`](../../crates/snapshot/src/snapshotter.rs#L20): A `reth` background service that **copies** data from the database to new snapshot files when the block height reaches a certain threshold (e.g., `500_000th`). Upon completion, it dispatches a notification about the higher snapshotted block to `HighestSnapshotTracker` channel. **It DOES NOT remove data from the database.** | ||
|
|
||
| [`HighestSnapshotTracker`](../../crates/snapshot/src/snapshotter.rs#L22): A channel utilized by `Snapshotter` to announce the newest snapshot block to all components with a listener: `Pruner` (to know which additional tables can be pruned) and `DatabaseProvider` (to know which data can be queried from the snapshots). |
There was a problem hiding this comment.
I see, so the HighestSnapshotTracker channel acts both as a notification about changed snapshot tracker (for pruner) and to track the highest snapshot (for database)
Comment on lines
+16
to
+19
| I("BLOCK_HEIGHT % 500_000 == 0")--triggers-->SP(Snapshotter) | ||
| SP --> |triggers| SH["create_snapshot(block_range, SnapshotSegment::Headers)"] | ||
| SP --> |triggers| ST["create_snapshot(block_range, SnapshotSegment::Transactions)"] | ||
| SP --> |triggers| SR["create_snapshot(block_range, SnapshotSegment::Receipts)"] |
There was a problem hiding this comment.
this should emphasize that this is a list of "segments", perhaps with an additional ... or a label
joshieDo
force-pushed
the
joshie/doc-snapshot
branch
from
f18d82c
to
ec32c36
Compare
joshieDo
force-pushed
the
joshie/doc-snapshot
branch
from
ec32c36
to
d4013d7
Compare
mattsse
approved these changes
Nov 2, 2023
shekhirin
approved these changes
Nov 2, 2023
crates/snapshot/README.md
Outdated
Comment on lines
27
to
29
| HN --> |true| NJC(NippyJar::Compression) | ||
| NJC --store--> NJ | ||
| HN --> |false| NJ |
There was a problem hiding this comment.
nit: it should probably point from NJC to HN in case it's true, so it'll be a while HasNext block. And on false, we can specify that we finished.
| PF--shares-->SP1("Arc(SnapshotProvider)") | ||
| SP1--shares-->PD(DatabaseProvider) | ||
| PF--creates-->PD | ||
| PD--check `HighestSnapshotTracker`-->PD |
There was a problem hiding this comment.
nit: I'd rather have a separate block for tracker, so it's visible that it's a separate entity defined in the previous diagram
There was a problem hiding this comment.
it becomes ugly in the diagram, i dont know how to force it to the side lol
crates/snapshot/README.md
Outdated
|
|
||
| [`NippyJarCursor`](../../crates/storage/nippy-jar/src/cursor.rs#L12) Accessor of data in a `NippyJar` file. It enables queries either by row number (e.g., block number 1) or by a predefined key not part of the file (e.g., transaction hashes). If a file has multiple columns (e.g., `Tx | TxSender | Signature`), and one wishes to access only one of the column values, this can be accomplished by bitmasks. (e.g., for `TxSender`, the mask would be `0b010`). | ||
|
|
||
| [`NippyJar`](../../crates/storage/nippy-jar/src/lib.rs#57) A create-only file format. No data can be appended after creation. It supports multiple columns, compression (e.g., Zstd (with and without dictionaries), lz4, uncompressed) and inclusion filters (e.g., cuckoo filter: `is hash X part of this dataset`). Snapshots are organized by block ranges. (e.g., `TransactionSnapshot_500_000.jar` contains a transaction per row for all transactions until block `500_000`). For more check the struct documentation. |
There was a problem hiding this comment.
so it's clear that we're talking about a range, not 0..=N
Suggested change
| [`NippyJar`](../../crates/storage/nippy-jar/src/lib.rs#57) A create-only file format. No data can be appended after creation. It supports multiple columns, compression (e.g., Zstd (with and without dictionaries), lz4, uncompressed) and inclusion filters (e.g., cuckoo filter: `is hash X part of this dataset`). Snapshots are organized by block ranges. (e.g., `TransactionSnapshot_500_000.jar` contains a transaction per row for all transactions until block `500_000`). For more check the struct documentation. | |
| [`NippyJar`](../../crates/storage/nippy-jar/src/lib.rs#57) A create-only file format. No data can be appended after creation. It supports multiple columns, compression (e.g., Zstd (with and without dictionaries), lz4, uncompressed) and inclusion filters (e.g., cuckoo filter: `is hash X part of this dataset`). Snapshots are organized by block ranges. (e.g., `TransactionSnapshot_500_000.jar` contains a transaction per row for all transactions from block `0` to block `500_000`). For more check the struct documentation. |
There was a problem hiding this comment.
oh btw does it actually contain 0..=500_000 or 0..500_000? 0 is genesis, but we snapshot it too iiuc?
joshieDo
force-pushed
the
joshie/doc-snapshot
branch
from
d5dd799
to
951686a
Compare
mattsse
pushed a commit
that referenced
this pull request
Nov 8, 2023
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Provides a current overview on how each component interacts with each other when creating a snapshot, or querying a bunch of them.
The glossary provides a brief summary of each component/struct alongside a link to the source code (which is documented), for a more detailed view.