db/state: give CommitmentDomain its own lock in TemporalMemBatch

db/state/temporal_mem_batch.go

@@ -64,8 +64,13 @@ type TemporalMemBatch struct {
 	inMemHistoryReads bool
 
 	latestStateLock sync.RWMutex
-	domains         [kv.DomainLen]map[string][]dataWithTxNum
-	storage         *btree2.Map[string, []dataWithTxNum] // TODO: replace hardcoded domain name to per-config configuration of available Guarantees/AccessMethods (range vs get)
+	// commitmentLock guards domains[kv.CommitmentDomain] only. Commitment branches
+	// are written by the calculator goroutine during the fold; keeping them off
+	// latestStateLock lets worker state reads run without contending those writes.
+	// Multi-domain ops (Flush/Unwind) take both, always latestStateLock first.
+	commitmentLock sync.RWMutex
+	domains        [kv.DomainLen]map[string][]dataWithTxNum
+	storage        *btree2.Map[string, []dataWithTxNum] // TODO: replace hardcoded domain name to per-config configuration of available Guarantees/AccessMethods (range vs get)
 
 	domainWriters [kv.DomainLen]*DomainBufferedWriter
 	iiWriters     []*InvertedIndexBufferedWriter
@@ -149,11 +154,26 @@ func (sd *TemporalMemBatch) putHistory(domain kv.Domain, k, v []byte, txNum uint
 	return sd.domainWriters[domain].PutWithPrev(k, v, txNum, preval)
 }
 
+// lockFor returns the latest-state lock guarding a single domain: CommitmentDomain
+// has its own lock, everything else shares latestStateLock.
+func (sd *TemporalMemBatch) lockFor(domain kv.Domain) *sync.RWMutex {
+	if domain == kv.CommitmentDomain {
+		return &sd.commitmentLock
+	}
+	return &sd.latestStateLock
+}
+
+// lockBoth/unlockBoth guard operations spanning all domains (Flush, Unwind).
+// Order is fixed — state before commitment — to avoid deadlock.
+func (sd *TemporalMemBatch) lockBoth()   { sd.latestStateLock.Lock(); sd.commitmentLock.Lock() }
+func (sd *TemporalMemBatch) unlockBoth() { sd.commitmentLock.Unlock(); sd.latestStateLock.Unlock() }
+
 // putLatest reports whether this write is a same-txNum update of the key,
 // replacing the key's last entry in place instead of appending a version.
 func (sd *TemporalMemBatch) putLatest(domain kv.Domain, key string, val []byte, txNum uint64) (sameTxNumUpdate bool) {
-	sd.latestStateLock.Lock()
-	defer sd.latestStateLock.Unlock()
+	l := sd.lockFor(domain)
+	l.Lock()
+	defer l.Unlock()
 
 	var updateMetrics = func(domain kv.Domain, putKeySize int, putValueSize int) {
 		sd.metrics.Lock()
@@ -234,14 +254,15 @@ func (sd *TemporalMemBatch) putLatest(domain kv.Domain, key string, val []byte,
 }
 
 func (sd *TemporalMemBatch) GetLatest(domain kv.Domain, key []byte) (v []byte, step kv.Step, ok bool) {
-	sd.latestStateLock.RLock()
-	defer sd.latestStateLock.RUnlock()
+	l := sd.lockFor(domain)
+	l.RLock()
+	defer l.RUnlock()
 	return sd.getLatest(domain, key)
 }
 
 // getLatest is the lock-free implementation of GetLatest.
-// The caller must already hold latestStateLock (either RLock or Lock),
-// e.g. from within an IteratePrefix callback.
+// The caller must already hold the domain's lock (see lockFor), either RLock or
+// Lock, e.g. from within an IteratePrefix callback.
 func (sd *TemporalMemBatch) getLatest(domain kv.Domain, key []byte) (v []byte, step kv.Step, ok bool) {
 	var unwoundLatest = func(domain kv.Domain, key string) (v []byte, step kv.Step, ok bool) {
 		if sd.unwindChangeset != nil {
@@ -290,8 +311,9 @@ func (sd *TemporalMemBatch) GetAsOf(domain kv.Domain, key []byte, ts uint64) (v
 	if !sd.inMemHistoryReads && domain != kv.ReceiptDomain {
 		return nil, false, errors.New("GetAsOf called on TemporalMemBatch with inMemHistoryReads disabled")
 	}
-	sd.latestStateLock.RLock()
-	defer sd.latestStateLock.RUnlock()
+	l := sd.lockFor(domain)
+	l.RLock()
+	defer l.RUnlock()
 
 	// unwoundLatest returns the pre-unwound-block value for a key that was
 	// modified by the unwound block. Only fires when ts is at-or-after the
@@ -363,8 +385,9 @@ func (sd *TemporalMemBatch) SizeEstimate() uint64 {
 }
 
 func (sd *TemporalMemBatch) IteratePrefix(domain kv.Domain, prefix []byte, roTx kv.Tx, it func(k []byte, v []byte) (cont bool, err error)) error {
-	sd.latestStateLock.RLock()
-	defer sd.latestStateLock.RUnlock()
+	l := sd.lockFor(domain)
+	l.RLock()
+	defer l.RUnlock()
 	var ramIter btree2.MapIter[string, []dataWithTxNum]
 	if domain == kv.StorageDomain {
 		ramIter = sd.storage.Iter()
@@ -420,8 +443,9 @@ func (sd *TemporalMemBatch) HasPrefix(domain kv.Domain, prefix []byte, roTx kv.T
 // for the given domain whose key starts with prefix.  It never touches disk or
 // segment files — only the in-memory btree (StorageDomain) or the domain map.
 func (sd *TemporalMemBatch) HasPrefixInRAM(domain kv.Domain, prefix []byte) bool {
-	sd.latestStateLock.RLock()
-	defer sd.latestStateLock.RUnlock()
+	l := sd.lockFor(domain)
+	l.RLock()
+	defer l.RUnlock()
 
 	if domain == kv.StorageDomain {
 		prefixStr := common.ToStringZeroCopy(prefix)
@@ -526,8 +550,8 @@ func (sd *TemporalMemBatch) GetDiffset(tx kv.RwTx, blockHash common.Hash, blockN
 
 // Unwind drops [unwindToTxNum, ∞)
 func (sd *TemporalMemBatch) Unwind(unwindToTxNum uint64, changeset *[kv.DomainLen][]kv.DomainEntryDiff) {
-	sd.latestStateLock.Lock()
-	defer sd.latestStateLock.Unlock()
+	sd.lockBoth()
+	defer sd.unlockBoth()
 
 	sd.unwindToTxNum = unwindToTxNum
 
@@ -763,11 +787,11 @@ func (sd *TemporalMemBatch) flushLocked(ctx context.Context, tx kv.RwTx) error {
 // Flush writes the mem-batch to tx. With kv.WithFlushCallback options, the
 // registered per-domain callback is invoked for every (key, value, step, txNum)
 // tuple after the MDBX write succeeds, so a downstream cache can never be left
-// ahead of MDBX. Runs under latestStateLock so the callback's snapshot matches
-// flush-time state.
+// ahead of MDBX. Runs under both latest-state locks so the callback's snapshot
+// matches flush-time state.
 func (sd *TemporalMemBatch) Flush(ctx context.Context, tx kv.RwTx, opts ...kv.FlushOption) error {
-	sd.latestStateLock.Lock()
-	defer sd.latestStateLock.Unlock()
+	sd.lockBoth()
+	defer sd.unlockBoth()
 
 	if err := sd.flushLocked(ctx, tx); err != nil {
 		return err
@@ -809,8 +833,8 @@ func (sd *TemporalMemBatch) Flush(ctx context.Context, tx kv.RwTx, opts ...kv.Fl
 // FlushWithCommitmentCallback flushes the batch then invokes cb per
 // commitment-domain tuple under the lock.
 func (sd *TemporalMemBatch) FlushWithCommitmentCallback(ctx context.Context, tx kv.RwTx, cb execctx.CommitmentFlushCallback) error {
-	sd.latestStateLock.Lock()
-	defer sd.latestStateLock.Unlock()
+	sd.lockBoth()
+	defer sd.unlockBoth()
 
 	if err := sd.flushLocked(ctx, tx); err != nil {
 		return err

db/state/temporal_mem_batch_test.go

@@ -17,13 +17,17 @@
 package state
 
 import (
+	"sync"
 	"testing"
 
+	btree2 "github.com/tidwall/btree"
+
 	"github.com/stretchr/testify/require"
 
 	"github.com/erigontech/erigon/common"
 	"github.com/erigontech/erigon/db/kv"
 	"github.com/erigontech/erigon/db/state/changeset"
+	"github.com/erigontech/erigon/db/state/kvmetrics"
 )
 
 // A reorg unwind restores domain values from the diffset, so a domain missing
@@ -45,3 +49,56 @@ func TestGetDiffsetCoversAllDomains(t *testing.T) {
 		require.NotEmpty(t, diffs[d], "domain %s missing from GetDiffset", d)
 	}
 }
+
+// CommitmentDomain is on its own lock, so the calculator can write commitment
+// branches while workers read the state domains without contending. Run under
+// -race: commitment write vs state read, state read/write, commitment
+// read/write, and the both-lock Unwind path (deadlock-freedom).
+func TestSplitLock_ConcurrentCommitmentWriteVsStateRead(t *testing.T) {
+	sd := &TemporalMemBatch{
+		stepSize: 1,
+		storage:  btree2.NewMap[string, []dataWithTxNum](128),
+		metrics:  kvmetrics.NewDomainMetrics(),
+	}
+	for i := range sd.domains {
+		sd.domains[i] = map[string][]dataWithTxNum{}
+	}
+	const nKeys = 512
+	mkKey := func(i int) string { return string([]byte{byte(i), byte(i >> 8)}) }
+	for i := range nKeys {
+		sd.putLatest(kv.AccountsDomain, mkKey(i), []byte{1}, uint64(i))
+	}
+
+	stop := make(chan struct{})
+	var writers, readers sync.WaitGroup
+
+	loopUntilStop := func(f func(i int)) {
+		defer writers.Done()
+		for i := 0; ; i++ {
+			select {
+			case <-stop:
+				return
+			default:
+				f(i)
+			}
+		}
+	}
+	writers.Add(3)
+	go loopUntilStop(func(i int) { sd.putLatest(kv.CommitmentDomain, mkKey(i&(nKeys-1)), []byte{byte(i)}, uint64(i)) })
+	go loopUntilStop(func(i int) { sd.putLatest(kv.AccountsDomain, mkKey(i&(nKeys-1)), []byte{byte(i)}, uint64(i)) })
+	go loopUntilStop(func(i int) { sd.Unwind(uint64(1_000_000+i), nil) }) // both-lock path; txNum far above data so nothing is pruned
+
+	readers.Add(8)
+	for range 8 {
+		go func() {
+			defer readers.Done()
+			for i := range 20_000 {
+				sd.GetLatest(kv.AccountsDomain, []byte(mkKey(i&(nKeys-1))))
+				sd.GetLatest(kv.CommitmentDomain, []byte(mkKey(i&(nKeys-1))))
+			}
+		}()
+	}
+	readers.Wait()
+	close(stop)
+	writers.Wait()
+}