core/state: value diff tracking in StateDB (#27349)

This change makes the StateDB track the state key value diff of a block transition.
We already tracked current account and storage values for the purpose of updating
the state snapshot. With this PR, we now also track the original (pre-transition) values
of accounts and storage slots.

core/state/dump.go

@@ -171,7 +171,7 @@ func (s *StateDB) DumpToCollector(c DumpCollector, conf *DumpConfig) (nextKey []
 		} else {
 			address = &addr
 		}
-		obj := newObject(s, addr, data)
+		obj := newObject(s, addr, &data)
 		if !conf.SkipCode {
 			account.Code = obj.Code(s.db)
 		}

core/state/journal.go

@@ -95,6 +95,10 @@ type (
 		prevdestruct bool
 		prevAccount  []byte
 		prevStorage  map[common.Hash][]byte
+
+		prevAccountOriginExist bool
+		prevAccountOrigin      []byte
+		prevStorageOrigin      map[common.Hash][]byte
 	}
 	suicideChange struct {
 		account     *common.Address
@@ -163,10 +167,16 @@ func (ch resetObjectChange) revert(s *StateDB) {
 		delete(s.stateObjectsDestruct, ch.prev.address)
 	}
 	if ch.prevAccount != nil {
-		s.snapAccounts[ch.prev.addrHash] = ch.prevAccount
+		s.accounts[ch.prev.addrHash] = ch.prevAccount
 	}
 	if ch.prevStorage != nil {
-		s.snapStorage[ch.prev.addrHash] = ch.prevStorage
+		s.storages[ch.prev.addrHash] = ch.prevStorage
+	}
+	if ch.prevAccountOriginExist {
+		s.accountsOrigin[ch.prev.addrHash] = ch.prevAccountOrigin
+	}
+	if ch.prevStorageOrigin != nil {
+		s.storagesOrigin[ch.prev.addrHash] = ch.prevStorageOrigin
 	}
 }
 

core/state/metrics.go

@@ -27,4 +27,11 @@ var (
 	storageTriesUpdatedMeter = metrics.NewRegisteredMeter("state/update/storagenodes", nil)
 	accountTrieDeletedMeter  = metrics.NewRegisteredMeter("state/delete/accountnodes", nil)
 	storageTriesDeletedMeter = metrics.NewRegisteredMeter("state/delete/storagenodes", nil)
+
+	slotDeletionMaxCount = metrics.NewRegisteredGauge("state/delete/storage/max/slot", nil)
+	slotDeletionMaxSize  = metrics.NewRegisteredGauge("state/delete/storage/max/size", nil)
+	slotDeletionTimer    = metrics.NewRegisteredResettingTimer("state/delete/storage/timer", nil)
+	slotDeletionCount    = metrics.NewRegisteredMeter("state/delete/storage/slot", nil)
+	slotDeletionSize     = metrics.NewRegisteredMeter("state/delete/storage/size", nil)
+	slotDeletionSkip     = metrics.NewRegisteredGauge("state/delete/storage/skip", nil)
 )

core/state/snapshot/generate.go

@@ -366,7 +366,7 @@ func (dl *diskLayer) generateRange(ctx *generatorContext, trieId *trie.ID, prefi
 			return false, nil, err
 		}
 		if nodes != nil {
-			tdb.Update(root, types.EmptyRootHash, trienode.NewWithNodeSet(nodes))
+			tdb.Update(root, types.EmptyRootHash, trienode.NewWithNodeSet(nodes), nil)
 			tdb.Commit(root, false)
 		}
 		resolver = func(owner common.Hash, path []byte, hash common.Hash) []byte {

core/state/snapshot/generate_test.go

@@ -203,7 +203,7 @@ func (t *testHelper) Commit() common.Hash {
 	if nodes != nil {
 		t.nodes.Merge(nodes)
 	}
-	t.triedb.Update(root, types.EmptyRootHash, t.nodes)
+	t.triedb.Update(root, types.EmptyRootHash, t.nodes, nil)
 	t.triedb.Commit(root, false)
 	return root
 }

core/state/state_object.go

@@ -57,29 +57,35 @@ func (s Storage) Copy() Storage {
 // stateObject represents an Ethereum account which is being modified.
 //
 // The usage pattern is as follows:
-// First you need to obtain a state object.
-// Account values can be accessed and modified through the object.
-// Finally, call commitTrie to write the modified storage trie into a database.
+// - First you need to obtain a state object.
+// - Account values as well as storages can be accessed and modified through the object.
+// - Finally, call commit to return the changes of storage trie and update account data.
 type stateObject struct {
-	address  common.Address
-	addrHash common.Hash // hash of ethereum address of the account
-	data     types.StateAccount
 	db       *StateDB
+	address  common.Address      // address of ethereum account
+	addrHash common.Hash         // hash of ethereum address of the account
+	origin   *types.StateAccount // Account original data without any change applied, nil means it was not existent
+	data     types.StateAccount  // Account data with all mutations applied in the scope of block
 
 	// Write caches.
 	trie Trie // storage trie, which becomes non-nil on first access
 	code Code // contract bytecode, which gets set when code is loaded
 
-	originStorage  Storage // Storage cache of original entries to dedup rewrites, reset for every transaction
+	originStorage  Storage // Storage cache of original entries to dedup rewrites
 	pendingStorage Storage // Storage entries that need to be flushed to disk, at the end of an entire block
-	dirtyStorage   Storage // Storage entries that have been modified in the current transaction execution
+	dirtyStorage   Storage // Storage entries that have been modified in the current transaction execution, reset for every transaction
 
 	// Cache flags.
-	// When an object is marked suicided it will be deleted from the trie
-	// during the "update" phase of the state transition.
 	dirtyCode bool // true if the code was updated
-	suicided  bool
-	deleted   bool
+
+	// Flag whether the account was marked as suicided. The suicided account
+	// is still accessible in the scope of same transaction.
+	suicided bool
+
+	// Flag whether the account was marked as deleted. The suicided account
+	// or the account is considered as empty will be marked as deleted at
+	// the end of transaction and no longer accessible anymore.
+	deleted bool
 }
 
 // empty returns whether the account is considered empty.
@@ -88,21 +94,17 @@ func (s *stateObject) empty() bool {
 }
 
 // newObject creates a state object.
-func newObject(db *StateDB, address common.Address, data types.StateAccount) *stateObject {
-	if data.Balance == nil {
-		data.Balance = new(big.Int)
-	}
-	if data.CodeHash == nil {
-		data.CodeHash = types.EmptyCodeHash.Bytes()
-	}
-	if data.Root == (common.Hash{}) {
-		data.Root = types.EmptyRootHash
+func newObject(db *StateDB, address common.Address, acct *types.StateAccount) *stateObject {
+	origin := acct
+	if acct == nil {
+		acct = types.NewEmptyStateAccount()
 	}
 	return &stateObject{
 		db:             db,
 		address:        address,
 		addrHash:       crypto.Keccak256Hash(address[:]),
-		data:           data,
+		origin:         origin,
+		data:           *acct,
 		originStorage:  make(Storage),
 		pendingStorage: make(Storage),
 		dirtyStorage:   make(Storage),
@@ -135,10 +137,8 @@ func (s *stateObject) touch() {
 func (s *stateObject) getTrie(db Database) (Trie, error) {
 	if s.trie == nil {
 		// Try fetching from prefetcher first
-		// We don't prefetch empty tries
 		if s.data.Root != types.EmptyRootHash && s.db.prefetcher != nil {
-			// When the miner is creating the pending state, there is no
-			// prefetcher
+			// When the miner is creating the pending state, there is no prefetcher
 			s.trie = s.db.prefetcher.trie(s.addrHash, s.data.Root)
 		}
 		if s.trie == nil {
@@ -277,6 +277,7 @@ func (s *stateObject) updateTrie(db Database) (Trie, error) {
 	// The snapshot storage map for the object
 	var (
 		storage map[common.Hash][]byte
+		origin  map[common.Hash][]byte
 		hasher  = s.db.hasher
 	)
 	tr, err := s.getTrie(db)
@@ -291,6 +292,7 @@ func (s *stateObject) updateTrie(db Database) (Trie, error) {
 		if value == s.originStorage[key] {
 			continue
 		}
+		prev := s.originStorage[key]
 		s.originStorage[key] = value
 
 		// rlp-encoded value to be used by the snapshot
@@ -311,17 +313,34 @@ func (s *stateObject) updateTrie(db Database) (Trie, error) {
 			}
 			s.db.StorageUpdated += 1
 		}
-		// If state snapshotting is active, cache the data til commit
-		if s.db.snap != nil {
-			if storage == nil {
-				// Retrieve the old storage map, if available, create a new one otherwise
-				if storage = s.db.snapStorage[s.addrHash]; storage == nil {
-					storage = make(map[common.Hash][]byte)
-					s.db.snapStorage[s.addrHash] = storage
-				}
+		// Cache the mutated storage slots until commit
+		if storage == nil {
+			if storage = s.db.storages[s.addrHash]; storage == nil {
+				storage = make(map[common.Hash][]byte)
+				s.db.storages[s.addrHash] = storage
+			}
+		}
+		khash := crypto.HashData(hasher, key[:])
+		storage[khash] = snapshotVal // snapshotVal will be nil if it's deleted
+
+		// Cache the original value of mutated storage slots
+		if origin == nil {
+			if origin = s.db.storagesOrigin[s.addrHash]; origin == nil {
+				origin = make(map[common.Hash][]byte)
+				s.db.storagesOrigin[s.addrHash] = origin
+			}
+		}
+		// Track the original value of slot only if it's mutated first time
+		if _, ok := origin[khash]; !ok {
+			if prev == (common.Hash{}) {
+				origin[khash] = nil // nil if it was not present previously
+			} else {
+				// Encoding []byte cannot fail, ok to ignore the error.
+				b, _ := rlp.EncodeToBytes(common.TrimLeftZeroes(prev[:]))
+				origin[khash] = b
 			}
-			storage[crypto.HashData(hasher, key[:])] = snapshotVal // will be nil if it's deleted
 		}
+		// Cache the items for preloading
 		usedStorage = append(usedStorage, common.CopyBytes(key[:])) // Copy needed for closure
 	}
 	if s.db.prefetcher != nil {
@@ -351,15 +370,15 @@ func (s *stateObject) updateRoot(db Database) {
 	s.data.Root = tr.Hash()
 }
 
-// commitTrie submits the storage changes into the storage trie and re-computes
-// the root. Besides, all trie changes will be collected in a nodeset and returned.
-func (s *stateObject) commitTrie(db Database) (*trienode.NodeSet, error) {
+// commit returns the changes made in storage trie and updates the account data.
+func (s *stateObject) commit(db Database) (*trienode.NodeSet, error) {
 	tr, err := s.updateTrie(db)
 	if err != nil {
 		return nil, err
 	}
 	// If nothing changed, don't bother with committing anything
 	if tr == nil {
+		s.origin = s.data.Copy()
 		return nil, nil
 	}
 	// Track the amount of time wasted on committing the storage trie
@@ -371,6 +390,9 @@ func (s *stateObject) commitTrie(db Database) (*trienode.NodeSet, error) {
 		return nil, err
 	}
 	s.data.Root = root
+
+	// Update original account data after commit
+	s.origin = s.data.Copy()
 	return nodes, nil
 }
 
@@ -410,18 +432,24 @@ func (s *stateObject) setBalance(amount *big.Int) {
 }
 
 func (s *stateObject) deepCopy(db *StateDB) *stateObject {
-	stateObject := newObject(db, s.address, s.data)
+	obj := &stateObject{
+		db:       db,
+		address:  s.address,
+		addrHash: s.addrHash,
+		origin:   s.origin,
+		data:     s.data,
+	}
 	if s.trie != nil {
-		stateObject.trie = db.db.CopyTrie(s.trie)
-	}
-	stateObject.code = s.code
-	stateObject.dirtyStorage = s.dirtyStorage.Copy()
-	stateObject.originStorage = s.originStorage.Copy()
-	stateObject.pendingStorage = s.pendingStorage.Copy()
-	stateObject.suicided = s.suicided
-	stateObject.dirtyCode = s.dirtyCode
-	stateObject.deleted = s.deleted
-	return stateObject
+		obj.trie = db.db.CopyTrie(s.trie)
+	}
+	obj.code = s.code
+	obj.dirtyStorage = s.dirtyStorage.Copy()
+	obj.originStorage = s.originStorage.Copy()
+	obj.pendingStorage = s.pendingStorage.Copy()
+	obj.suicided = s.suicided
+	obj.dirtyCode = s.dirtyCode
+	obj.deleted = s.deleted
+	return obj
 }
 
 //

core/state/state_test.go

@@ -30,22 +30,22 @@ import (
 	"github.com/ethereum/go-ethereum/trie"
 )
 
-type stateTest struct {
+type stateEnv struct {
 	db    ethdb.Database
 	state *StateDB
 }
 
-func newStateTest() *stateTest {
+func newStateEnv() *stateEnv {
 	db := rawdb.NewMemoryDatabase()
 	sdb, _ := New(types.EmptyRootHash, NewDatabase(db), nil)
-	return &stateTest{db: db, state: sdb}
+	return &stateEnv{db: db, state: sdb}
 }
 
 func TestDump(t *testing.T) {
 	db := rawdb.NewMemoryDatabase()
 	tdb := NewDatabaseWithConfig(db, &trie.Config{Preimages: true})
 	sdb, _ := New(types.EmptyRootHash, tdb, nil)
-	s := &stateTest{db: db, state: sdb}
+	s := &stateEnv{db: db, state: sdb}
 
 	// generate a few entries
 	obj1 := s.state.GetOrNewStateObject(common.BytesToAddress([]byte{0x01}))
@@ -99,7 +99,7 @@ func TestIterativeDump(t *testing.T) {
 	db := rawdb.NewMemoryDatabase()
 	tdb := NewDatabaseWithConfig(db, &trie.Config{Preimages: true})
 	sdb, _ := New(types.EmptyRootHash, tdb, nil)
-	s := &stateTest{db: db, state: sdb}
+	s := &stateEnv{db: db, state: sdb}
 
 	// generate a few entries
 	obj1 := s.state.GetOrNewStateObject(common.BytesToAddress([]byte{0x01}))
@@ -133,7 +133,7 @@ func TestIterativeDump(t *testing.T) {
 }
 
 func TestNull(t *testing.T) {
-	s := newStateTest()
+	s := newStateEnv()
 	address := common.HexToAddress("0x823140710bf13990e4500136726d8b55")
 	s.state.CreateAccount(address)
 	//value := common.FromHex("0x823140710bf13990e4500136726d8b55")
@@ -155,7 +155,7 @@ func TestSnapshot(t *testing.T) {
 	var storageaddr common.Hash
 	data1 := common.BytesToHash([]byte{42})
 	data2 := common.BytesToHash([]byte{43})
-	s := newStateTest()
+	s := newStateEnv()
 
 	// snapshot the genesis state
 	genesis := s.state.Snapshot()
@@ -186,7 +186,7 @@ func TestSnapshot(t *testing.T) {
 }
 
 func TestSnapshotEmpty(t *testing.T) {
-	s := newStateTest()
+	s := newStateEnv()
 	s.state.RevertToSnapshot(s.state.Snapshot())
 }