triedb/pathdb: track flat state changes in pathdb (snapshot integration pt 2)

triedb/database.go

@@ -60,6 +60,10 @@ type backend interface {
 	// An error will be returned if the specified state is not available.
 	NodeReader(root common.Hash) (database.NodeReader, error)
 
+	// StateReader returns a reader for accessing flat states within the specified
+	// state. An error will be returned if the specified state is not available.
+	StateReader(root common.Hash) (database.StateReader, error)
+
 	// Initialized returns an indicator if the state data is already initialized
 	// according to the state scheme.
 	Initialized(genesisRoot common.Hash) bool
@@ -122,6 +126,13 @@ func (db *Database) NodeReader(blockRoot common.Hash) (database.NodeReader, erro
 	return db.backend.NodeReader(blockRoot)
 }
 
+// StateReader returns a reader that allows access to the state data associated
+// with the specified state. An error will be returned if the specified state is
+// not available.
+func (db *Database) StateReader(blockRoot common.Hash) (database.StateReader, error) {
+	return db.backend.StateReader(blockRoot)
+}
+
 // Update performs a state transition by committing dirty nodes contained in the
 // given set in order to update state from the specified parent to the specified
 // root. The held pre-images accumulated up to this point will be flushed in case

triedb/database/database.go

@@ -18,6 +18,7 @@ package database
 
 import (
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
 )
 
 // NodeReader wraps the Node method of a backing trie reader.
@@ -37,3 +38,31 @@ type NodeDatabase interface {
 	// An error will be returned if the specified state is not available.
 	NodeReader(stateRoot common.Hash) (NodeReader, error)
 }
+
+// StateReader wraps the Account and Storage method of a backing state reader.
+type StateReader interface {
+	// Account directly retrieves the account associated with a particular hash in
+	// the slim data format. An error will be returned if the read operation exits
+	// abnormally. Specifically, if the layer is already stale.
+	//
+	// Note:
+	// - the returned account object is safe to modify
+	// - no error will be returned if the requested account is not found in database
+	Account(hash common.Hash) (*types.SlimAccount, error)
+
+	// Storage directly retrieves the storage data associated with a particular hash,
+	// within a particular account. An error will be returned if the read operation
+	// exits abnormally.
+	//
+	// Note:
+	// - the returned storage data is not a copy, please don't modify it
+	// - no error will be returned if the requested slot is not found in database
+	Storage(accountHash, storageHash common.Hash) ([]byte, error)
+}
+
+// StateDatabase warps the methods of a backing state store.
+type StateDatabase interface {
+	// StateReader returns a state reader associated with the specific state.
+	// An error will be returned if the specified state is not available.
+	StateReader(stateRoot common.Hash) (StateReader, error)
+}

triedb/hashdb/database.go

@@ -635,3 +635,9 @@ func (reader *reader) Node(owner common.Hash, path []byte, hash common.Hash) ([]
 	blob, _ := reader.db.node(hash)
 	return blob, nil
 }
+
+// StateReader returns a reader that allows access to the state data associated
+// with the specified state.
+func (db *Database) StateReader(root common.Hash) (database.StateReader, error) {
+	return nil, errors.New("not implemented")
+}

triedb/pathdb/buffer.go

@@ -33,40 +33,56 @@ import (
 // must be checked before diving into disk (since it basically is not yet written
 // data).
 type buffer struct {
-	layers uint64   // The number of diff layers aggregated inside
-	limit  uint64   // The maximum memory allowance in bytes
-	nodes  *nodeSet // Aggregated trie node set
+	layers uint64    // The number of diff layers aggregated inside
+	limit  uint64    // The maximum memory allowance in bytes
+	nodes  *nodeSet  // Aggregated trie node set
+	states *stateSet // Aggregated state set
 }
 
 // newBuffer initializes the buffer with the provided states and trie nodes.
-func newBuffer(limit int, nodes *nodeSet, layers uint64) *buffer {
+func newBuffer(limit int, nodes *nodeSet, states *stateSet, layers uint64) *buffer {
 	// Don't panic for lazy users if any provided set is nil
 	if nodes == nil {
 		nodes = newNodeSet(nil)
 	}
+	if states == nil {
+		states = newStates(nil, nil, nil)
+	}
 	return &buffer{
 		layers: layers,
 		limit:  uint64(limit),
 		nodes:  nodes,
+		states: states,
 	}
 }
 
+// account retrieves the account blob with account address hash.
+func (b *buffer) account(hash common.Hash) ([]byte, bool) {
+	return b.states.account(hash)
+}
+
+// storage retrieves the storage slot with account address hash and slot key.
+func (b *buffer) storage(addrHash common.Hash, storageHash common.Hash) ([]byte, bool) {
+	return b.states.storage(addrHash, storageHash)
+}
+
 // node retrieves the trie node with node path and its trie identifier.
 func (b *buffer) node(owner common.Hash, path []byte) (*trienode.Node, bool) {
 	return b.nodes.node(owner, path)
 }
 
 // commit merges the provided states and trie nodes into the buffer.
-func (b *buffer) commit(nodes *nodeSet) *buffer {
+func (b *buffer) commit(nodes *nodeSet, states *stateSet) *buffer {
 	b.layers++
 	b.nodes.merge(nodes)
+	b.states.merge(states)
 	return b
 }
 
 // revert is the reverse operation of commit. It also merges the provided states
 // and trie nodes into the buffer. The key difference is that the provided state
 // set should reverse the changes made by the most recent state transition.
-func (b *buffer) revert(db ethdb.KeyValueReader, nodes map[common.Hash]map[string]*trienode.Node) error {
+func (b *buffer) revert(db ethdb.KeyValueReader, nodes map[common.Hash]map[string]*trienode.Node, accounts map[common.Hash][]byte, storages map[common.Hash]map[common.Hash][]byte) error {
 	// Short circuit if no embedded state transition to revert
 	if b.layers == 0 {
 		return errStateUnrecoverable
@@ -79,13 +95,15 @@ func (b *buffer) revert(db ethdb.KeyValueReader, nodes map[common.Hash]map[strin
 		return nil
 	}
 	b.nodes.revert(db, nodes)
+	b.states.revert(accounts, storages)
 	return nil
 }
 
 // reset cleans up the disk cache.
 func (b *buffer) reset() {
 	b.layers = 0
 	b.nodes.reset()
+	b.states.reset()
 }
 
 // empty returns an indicator if buffer is empty.
@@ -101,7 +119,7 @@ func (b *buffer) full() bool {
 
 // size returns the approximate memory size of the held content.
 func (b *buffer) size() uint64 {
-	return b.nodes.size
+	return b.states.size + b.nodes.size
 }
 
 // flush persists the in-memory dirty trie node into the disk if the configured

triedb/pathdb/database.go

@@ -68,6 +68,24 @@ type layer interface {
 	// - no error will be returned if the requested node is not found in database.
 	node(owner common.Hash, path []byte, depth int) ([]byte, common.Hash, *nodeLoc, error)
 
+	// account directly retrieves the account RLP associated with a particular
+	// hash in the slim data format. An error will be returned if the read
+	// operation exits abnormally. Specifically, if the layer is already stale.
+	//
+	// Note:
+	// - the returned account is not a copy, please don't modify it.
+	// - no error will be returned if the requested account is not found in database.
+	account(hash common.Hash, depth int) ([]byte, error)
+
+	// storage directly retrieves the storage data associated with a particular hash,
+	// within a particular account. An error will be returned if the read operation
+	// exits abnormally. Specifically, if the layer is already stale.
+	//
+	// Note:
+	// - the returned storage data is not a copy, please don't modify it.
+	// - no error will be returned if the requested slot is not found in database.
+	storage(accountHash, storageHash common.Hash, depth int) ([]byte, error)
+
 	// rootHash returns the root hash for which this layer was made.
 	rootHash() common.Hash
 
@@ -130,17 +148,18 @@ var Defaults = &Config{
 // ReadOnly is the config in order to open database in read only mode.
 var ReadOnly = &Config{ReadOnly: true}
 
-// Database is a multiple-layered structure for maintaining in-memory trie nodes.
-// It consists of one persistent base layer backed by a key-value store, on top
-// of which arbitrarily many in-memory diff layers are stacked. The memory diffs
-// can form a tree with branching, but the disk layer is singleton and common to
-// all. If a reorg goes deeper than the disk layer, a batch of reverse diffs can
-// be applied to rollback. The deepest reorg that can be handled depends on the
-// amount of state histories tracked in the disk.
+// Database is a multiple-layered structure for maintaining in-memory states
+// along with its dirty trie nodes. It consists of one persistent base layer
+// backed by a key-value store, on top of which arbitrarily many in-memory diff
+// layers are stacked. The memory diffs can form a tree with branching, but the
+// disk layer is singleton and common to all. If a reorg goes deeper than the
+// disk layer, a batch of reverse diffs can be applied to rollback. The deepest
+// reorg that can be handled depends on the amount of state histories tracked
+// in the disk.
 //
 // At most one readable and writable database can be opened at the same time in
-// the whole system which ensures that only one database writer can operate disk
-// state. Unexpected open operations can cause the system to panic.
+// the whole system which ensures that only one database writer can operate the
+// persistent state. Unexpected open operations can cause the system to panic.
 type Database struct {
 	// readOnly is the flag whether the mutation is allowed to be applied.
 	// It will be set automatically when the database is journaled during
@@ -358,7 +377,7 @@ func (db *Database) Enable(root common.Hash) error {
 	}
 	// Re-construct a new disk layer backed by persistent state
 	// with **empty clean cache and node buffer**.
-	db.tree.reset(newDiskLayer(root, 0, db, nil, newBuffer(db.config.WriteBufferSize, nil, 0)))
+	db.tree.reset(newDiskLayer(root, 0, db, nil, newBuffer(db.config.WriteBufferSize, nil, nil, 0)))
 
 	// Re-enable the database as the final step.
 	db.waitSync = false

triedb/pathdb/database_test.go

@@ -309,7 +309,18 @@ func (t *tester) generate(parent common.Hash) (common.Hash, *trienode.MergedNode
 			delete(t.storages, addrHash)
 		}
 	}
-	return root, ctx.nodes, NewStateSetWithOrigin(ctx.accountOrigin, ctx.storageOrigin)
+	var (
+		accounts  = make(map[common.Hash][]byte)
+		destructs = make(map[common.Hash]struct{})
+	)
+	for addrHash, data := range ctx.accounts {
+		if len(data) == 0 {
+			destructs[addrHash] = struct{}{}
+		} else {
+			accounts[addrHash] = data
+		}
+	}
+	return root, ctx.nodes, NewStateSetWithOrigin(destructs, accounts, ctx.storages, ctx.accountOrigin, ctx.storageOrigin)
 }
 
 // lastHash returns the latest root hash, or empty if nothing is cached.

triedb/pathdb/difflayer.go

@@ -52,6 +52,7 @@ func newDiffLayer(parent layer, root common.Hash, id uint64, block uint64, nodes
 		states: states,
 	}
 	dirtyNodeWriteMeter.Mark(int64(nodes.size))
+	dirtyStateWriteMeter.Mark(int64(states.size))
 	log.Debug("Created new diff layer", "id", id, "block", block, "nodesize", common.StorageSize(nodes.size), "statesize", common.StorageSize(states.size))
 	return dl
 }
@@ -96,6 +97,58 @@ func (dl *diffLayer) node(owner common.Hash, path []byte, depth int) ([]byte, co
 	return dl.parent.node(owner, path, depth+1)
 }
 
+// account directly retrieves the account RLP associated with a particular
+// hash in the slim data format.
+//
+// Note the returned account is not a copy, please don't modify it.
+func (dl *diffLayer) account(hash common.Hash, depth int) ([]byte, error) {
+	// Hold the lock, ensure the parent won't be changed during the
+	// state accessing.
+	dl.lock.RLock()
+	defer dl.lock.RUnlock()
+
+	if blob, found := dl.states.account(hash); found {
+		dirtyStateHitMeter.Mark(1)
+		dirtyStateHitDepthHist.Update(int64(depth))
+		dirtyStateReadMeter.Mark(int64(len(blob)))
+
+		if len(blob) == 0 {
+			stateAccountMissMeter.Mark(1)
+		} else {
+			stateAccountHitMeter.Mark(1)
+		}
+		return blob, nil
+	}
+	// Account is unknown to this layer, resolve from parent
+	return dl.parent.account(hash, depth+1)
+}
+
+// storage directly retrieves the storage data associated with a particular hash,
+// within a particular account.
+//
+// Note the returned account is not a copy, please don't modify it.
+func (dl *diffLayer) storage(accountHash, storageHash common.Hash, depth int) ([]byte, error) {
+	// Hold the lock, ensure the parent won't be changed during the
+	// state accessing.
+	dl.lock.RLock()
+	defer dl.lock.RUnlock()
+
+	if blob, found := dl.states.storage(accountHash, storageHash); found {
+		dirtyStateHitMeter.Mark(1)
+		dirtyStateHitDepthHist.Update(int64(depth))
+		dirtyStateReadMeter.Mark(int64(len(blob)))
+
+		if len(blob) == 0 {
+			stateStorageMissMeter.Mark(1)
+		} else {
+			stateStorageHitMeter.Mark(1)
+		}
+		return blob, nil
+	}
+	// storage slot is unknown to this layer, resolve from parent
+	return dl.parent.storage(accountHash, storageHash, depth+1)
+}
+
 // update implements the layer interface, creating a new layer on top of the
 // existing layer tree with the specified data items.
 func (dl *diffLayer) update(root common.Hash, id uint64, block uint64, nodes *nodeSet, states *StateSetWithOrigin) *diffLayer {

triedb/pathdb/difflayer_test.go

@@ -30,7 +30,7 @@ import (
 func emptyLayer() *diskLayer {
 	return &diskLayer{
 		db:     New(rawdb.NewMemoryDatabase(), nil, false),
-		buffer: newBuffer(defaultBufferSize, nil, 0),
+		buffer: newBuffer(defaultBufferSize, nil, nil, 0),
 	}
 }