soft truncate head

core/blockchain.go

@@ -994,15 +994,6 @@ func (bc *BlockChain) setHeadBeyondRoot(head uint64, time uint64, root common.Ha
 		// and the current freezer limit to start nuking it's underflown.
 		pivot = rawdb.ReadLastPivotNumber(bc.db)
 	)
-	const truncateInterval = 100
-	truncateFn := func() {
-		// Truncate triedb to align the state histories with the current state.
-		if bc.triedb.Scheme() == rawdb.PathScheme {
-			if err := bc.triedb.TruncateHead(); err != nil {
-				log.Crit("Failed to truncate trie database", "err", err)
-			}
-		}
-	}
 	updateFn := func(db ethdb.KeyValueWriter, header *types.Header) (*types.Header, bool) {
 		// Rewind the blockchain, ensuring we don't end up with a stateless head
 		// block. Note, depth equality is permitted to allow using SetHead as a
@@ -1012,9 +1003,11 @@ func (bc *BlockChain) setHeadBeyondRoot(head uint64, time uint64, root common.Ha
 			newHeadBlock, rootNumber = bc.rewindHead(header, root)
 			rawdb.WriteHeadBlockHash(db, newHeadBlock.Hash())
 
-			// The truncate costs a lot of time, no need to run for each block
-			if header.Number.Uint64()%truncateInterval == 0 {
-				truncateFn()
+			// Use soft truncate for fast rewind - actual truncation happens at the end
+			if bc.triedb.Scheme() == rawdb.PathScheme {
+				if err := bc.triedb.SoftTruncateHead(); err != nil {
+					log.Warn("Failed to soft truncate trie database", "err", err)
+				}
 			}
 
 			// Degrade the chain markers if they are explicitly reverted.
@@ -1110,8 +1103,12 @@ func (bc *BlockChain) setHeadBeyondRoot(head uint64, time uint64, root common.Ha
 	bc.blockCache.Purge()
 	bc.txLookupCache.Purge()
 
-	// Truncate to align the state histories with the current state.
-	truncateFn()
+	// Commit all soft truncations to align the state histories with the current state.
+	if bc.triedb.Scheme() == rawdb.PathScheme {
+		if err := bc.triedb.CommitTruncation(); err != nil {
+			log.Crit("Failed to commit trie database truncation", "err", err)
+		}
+	}
 
 	// Clear safe block, finalized block if needed
 	if safe := bc.CurrentSafeBlock(); safe != nil && head < safe.Number.Uint64() {

core/rawdb/chain_freezer.go

@@ -415,6 +415,14 @@ func (f *chainFreezer) TruncateTail(items uint64) (uint64, error) {
 	return f.ancients.TruncateTail(items)
 }
 
+func (f *chainFreezer) SoftTruncateHead(items uint64) (uint64, error) {
+	return f.ancients.SoftTruncateHead(items)
+}
+
+func (f *chainFreezer) CommitTruncation() error {
+	return f.ancients.CommitTruncation()
+}
+
 func (f *chainFreezer) SyncAncient() error {
 	return f.ancients.SyncAncient()
 }

core/rawdb/database.go

@@ -130,6 +130,16 @@ func (db *nofreezedb) TruncateTail(items uint64) (uint64, error) {
 	return 0, errNotSupported
 }
 
+// SoftTruncateHead returns an error as we don't have a backing chain freezer.
+func (db *nofreezedb) SoftTruncateHead(items uint64) (uint64, error) {
+	return 0, errNotSupported
+}
+
+// CommitTruncation returns an error as we don't have a backing chain freezer.
+func (db *nofreezedb) CommitTruncation() error {
+	return errNotSupported
+}
+
 // SyncAncient returns an error as we don't have a backing chain freezer.
 func (db *nofreezedb) SyncAncient() error {
 	return errNotSupported

core/rawdb/freezer.go

@@ -61,6 +61,7 @@ type Freezer struct {
 	datadir string
 	frozen  atomic.Uint64 // Number of items already frozen
 	tail    atomic.Uint64 // Number of the first stored item in the freezer
+	vHead   atomic.Uint64 // Virtual head for soft truncation (0 means not set)
 
 	// This lock synchronizes writers and the truncate operation, as well as
 	// the "atomic" (batched) read operations.
@@ -203,6 +204,10 @@ func (f *Freezer) AncientRange(kind string, start, count, maxBytes uint64) ([][]
 
 // Ancients returns the length of the frozen items.
 func (f *Freezer) Ancients() (uint64, error) {
+	vHead := f.vHead.Load()
+	if vHead > 0 {
+		return vHead, nil
+	}
 	return f.frozen.Load(), nil
 }
 
@@ -313,6 +318,61 @@ func (f *Freezer) TruncateTail(tail uint64) (uint64, error) {
 	return old, nil
 }
 
+// SoftTruncateHead marks items above threshold as logically deleted without physical truncation.
+// This is much faster than TruncateHead as it only updates a pointer.
+func (f *Freezer) SoftTruncateHead(items uint64) (uint64, error) {
+	if f.readonly {
+		return 0, errReadOnly
+	}
+
+	frozen := f.frozen.Load()
+	vHead := f.vHead.Load()
+
+	// Determine the current effective head
+	var currentHead uint64
+	if vHead > 0 {
+		currentHead = vHead
+	} else {
+		currentHead = frozen
+	}
+
+	if currentHead <= items {
+		return currentHead, nil
+	}
+
+	// Ensure we don't truncate below the tail
+	tail := f.tail.Load()
+	if items < tail {
+		return 0, fmt.Errorf("soft truncate below tail: tail=%d, target=%d", tail, items)
+	}
+
+	f.vHead.Store(items)
+	return currentHead, nil
+}
+
+// CommitTruncation performs the actual file truncation to match virtual head.
+// This should be called after all soft truncations are complete.
+func (f *Freezer) CommitTruncation() error {
+	if f.readonly {
+		return errReadOnly
+	}
+
+	vHead := f.vHead.Load()
+	if vHead == 0 {
+		return nil // No pending truncation
+	}
+
+	// Perform the actual truncation
+	_, err := f.TruncateHead(vHead)
+	if err != nil {
+		return err
+	}
+
+	// Clear virtual head since we've committed
+	f.vHead.Store(0)
+	return nil
+}
+
 // SyncAncient flushes all data tables to disk.
 func (f *Freezer) SyncAncient() error {
 	var errs []error

core/rawdb/freezer_memory.go

@@ -205,6 +205,7 @@ func (b *memoryBatch) commit(freezer *MemoryFreezer) (items uint64, writeSize in
 type MemoryFreezer struct {
 	items      uint64                  // Number of items stored
 	tail       uint64                  // Number of the first stored item in the freezer
+	vHead      uint64                  // Virtual head for soft truncation (0 means not set)
 	readonly   bool                    // Flag if the freezer is only for reading
 	lock       sync.RWMutex            // Lock to protect fields
 	tables     map[string]*memoryTable // Tables for storing everything
@@ -262,6 +263,9 @@ func (f *MemoryFreezer) Ancients() (uint64, error) {
 	f.lock.RLock()
 	defer f.lock.RUnlock()
 
+	if f.vHead > 0 {
+		return f.vHead, nil
+	}
 	return f.items, nil
 }
 
@@ -338,17 +342,10 @@ func (f *MemoryFreezer) TruncateHead(items uint64) (uint64, error) {
 	if f.readonly {
 		return 0, errReadOnly
 	}
-	old := f.items
-	if old <= items {
-		return old, nil
-	}
-	for _, table := range f.tables {
-		if err := table.truncateHead(items); err != nil {
-			return 0, err
-		}
-	}
-	f.items = items
-	return old, nil
+
+	// Clear virtual head if we're doing a real truncation
+	f.vHead = 0
+	return f.truncateHead(items)
 }
 
 // TruncateTail discards all data below the provided threshold number.
@@ -376,6 +373,75 @@ func (f *MemoryFreezer) TruncateTail(tail uint64) (uint64, error) {
 	return old, nil
 }
 
+// SoftTruncateHead marks items above threshold as logically deleted without physical truncation.
+func (f *MemoryFreezer) SoftTruncateHead(items uint64) (uint64, error) {
+	f.lock.Lock()
+	defer f.lock.Unlock()
+
+	if f.readonly {
+		return 0, errReadOnly
+	}
+
+	// Determine the current effective head
+	var currentHead uint64
+	if f.vHead > 0 {
+		currentHead = f.vHead
+	} else {
+		currentHead = f.items
+	}
+
+	if currentHead <= items {
+		return currentHead, nil
+	}
+
+	// Ensure we don't truncate below the tail
+	if items < f.tail {
+		return 0, fmt.Errorf("soft truncate below tail: tail=%d, target=%d", f.tail, items)
+	}
+
+	f.vHead = items
+	return currentHead, nil
+}
+
+// CommitTruncation performs the actual truncation to match virtual head.
+func (f *MemoryFreezer) CommitTruncation() error {
+	f.lock.Lock()
+	defer f.lock.Unlock()
+
+	if f.readonly {
+		return errReadOnly
+	}
+
+	if f.vHead == 0 {
+		return nil // No pending truncation
+	}
+
+	// Perform the actual truncation
+	_, err := f.truncateHead(f.vHead)
+	if err != nil {
+		return err
+	}
+
+	// Clear virtual head since we've committed
+	f.vHead = 0
+	return nil
+}
+
+// truncateHead is the internal method that does the actual head truncation.
+func (f *MemoryFreezer) truncateHead(items uint64) (uint64, error) {
+	old := f.items
+	if old <= items {
+		return old, nil
+	}
+	for _, table := range f.tables {
+		if err := table.truncateHead(items); err != nil {
+			return 0, err
+		}
+	}
+	f.items = items
+	return old, nil
+}
+
 // SyncAncient flushes all data tables to disk.
 func (f *MemoryFreezer) SyncAncient() error {
 	return nil

core/rawdb/freezer_resettable.go

@@ -185,6 +185,22 @@ func (f *resettableFreezer) TruncateTail(tail uint64) (uint64, error) {
 	return f.freezer.TruncateTail(tail)
 }
 
+// SoftTruncateHead marks items above threshold as logically deleted without physical truncation.
+func (f *resettableFreezer) SoftTruncateHead(items uint64) (uint64, error) {
+	f.lock.RLock()
+	defer f.lock.RUnlock()
+
+	return f.freezer.SoftTruncateHead(items)
+}
+
+// CommitTruncation performs the actual file truncation to match any soft truncations.
+func (f *resettableFreezer) CommitTruncation() error {
+	f.lock.RLock()
+	defer f.lock.RUnlock()
+
+	return f.freezer.CommitTruncation()
+}
+
 // SyncAncient flushes all data tables to disk.
 func (f *resettableFreezer) SyncAncient() error {
 	f.lock.RLock()

core/rawdb/table.go

@@ -101,6 +101,18 @@ func (t *table) TruncateTail(items uint64) (uint64, error) {
 	return t.db.TruncateTail(items)
 }
 
+// SoftTruncateHead is a noop passthrough that just forwards the request to the underlying
+// database.
+func (t *table) SoftTruncateHead(items uint64) (uint64, error) {
+	return t.db.SoftTruncateHead(items)
+}
+
+// CommitTruncation is a noop passthrough that just forwards the request to the underlying
+// database.
+func (t *table) CommitTruncation() error {
+	return t.db.CommitTruncation()
+}
+
 // SyncAncient is a noop passthrough that just forwards the request to the underlying
 // database.
 func (t *table) SyncAncient() error {

ethdb/database.go

@@ -163,6 +163,14 @@ type AncientWriter interface {
 	//
 	// Note that data marked as non-prunable will still be retained and remain accessible.
 	TruncateTail(n uint64) (uint64, error)
+
+	// SoftTruncateHead marks items above threshold as logically deleted without physical truncation.
+	// This is much faster than TruncateHead as it only updates a pointer.
+	SoftTruncateHead(n uint64) (uint64, error)
+
+	// CommitTruncation performs the actual file truncation to match any soft truncations.
+	// This should be called after all soft truncations are complete.
+	CommitTruncation() error
 }
 
 // AncientWriteOp is given to the function argument of ModifyAncients.

ethdb/remotedb/remotedb.go

@@ -140,6 +140,16 @@ func (db *Database) Close() error {
 	return nil
 }
 
+// SoftTruncateHead returns an error as we don't have a backing chain freezer.
+func (db *Database) SoftTruncateHead(items uint64) (uint64, error) {
+	panic("not supported")
+}
+
+// CommitTruncation returns an error as we don't have a backing chain freezer.
+func (db *Database) CommitTruncation() error {
+	panic("not supported")
+}
+
 func New(client *rpc.Client) ethdb.Database {
 	if client == nil {
 		return nil

triedb/database.go

@@ -291,6 +291,26 @@ func (db *Database) TruncateHead() error {
 	return pdb.TruncateHead()
 }
 
+// SoftTruncateHead marks state histories above the bottom state layer as logically deleted
+// without physical truncation. This is much faster than TruncateHead.
+func (db *Database) SoftTruncateHead() error {
+	pdb, ok := db.backend.(*pathdb.Database)
+	if !ok {
+		return errors.New("not supported")
+	}
+	return pdb.SoftTruncateHead()
+}
+
+// CommitTruncation performs the actual file truncation to match any soft truncations.
+// This should be called after all soft truncations are complete.
+func (db *Database) CommitTruncation() error {
+	pdb, ok := db.backend.(*pathdb.Database)
+	if !ok {
+		return errors.New("not supported")
+	}
+	return pdb.CommitTruncation()
+}
+
 // Recoverable returns the indicator if the specified state is enabled to be
 // recovered. It's only supported by path-based database and will return an
 // error for others.

triedb/pathdb/database.go

@@ -512,6 +512,19 @@ func (db *Database) TruncateHead() error {
 	return err
 }
 
+// SoftTruncateHead marks state histories above the bottom state layer as logically deleted
+// without physical truncation. This is much faster than TruncateHead.
+func (db *Database) SoftTruncateHead() error {
+	_, err := db.stateFreezer.SoftTruncateHead(db.tree.bottom().stateID())
+	return err
+}
+
+// CommitTruncation performs the actual file truncation to match any soft truncations.
+// This should be called after all soft truncations are complete.
+func (db *Database) CommitTruncation() error {
+	return db.stateFreezer.CommitTruncation()
+}
+
 // Recoverable returns the indicator if the specified state is recoverable.
 //
 // The supplied root must be a valid trie hash value.

triedb/pathdb/database_test.go

@@ -600,8 +600,11 @@ func TestDatabaseRollback(t *testing.T) {
 		if err := tester.db.Recover(parent); err != nil {
 			t.Fatalf("Failed to revert db, err: %v", err)
 		}
-		if err := tester.db.TruncateHead(); err != nil {
-			t.Fatalf("Failed to truncate head, err: %v", err)
+		if err := tester.db.SoftTruncateHead(); err != nil {
+			t.Fatalf("Failed to soft truncate head, err: %v", err)
+		}
+		if err := tester.db.CommitTruncation(); err != nil {
+			t.Fatalf("Failed to commit truncation, err: %v", err)
 		}
 		if i > 0 {
 			if err := tester.verifyState(parent); err != nil {