statesync: copy state by swapping prefix

Signed-off-by: Evgeniy Stratonikov <evgeniy@nspcc.ru>

pkg/core/blockchain.go

@@ -36,7 +36,6 @@ import (
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/manifest"
 	"github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger"
 	"github.com/nspcc-dev/neo-go/pkg/util"
-	"github.com/nspcc-dev/neo-go/pkg/util/slice"
 	"github.com/nspcc-dev/neo-go/pkg/vm"
 	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
 	"go.uber.org/zap"
@@ -57,11 +56,6 @@ const (
 	// HeaderVerificationGasLimit is the maximum amount of GAS for block header verification.
 	HeaderVerificationGasLimit = 3_00000000 // 3 GAS
 	defaultStateSyncInterval   = 40000
-
-	// maxStorageBatchSize is the number of elements in storage batch expected to fit into the
-	// storage without delays and problems. Estimated size of batch in case of given number of
-	// elements does not exceed 1Mb.
-	maxStorageBatchSize = 10000
 )
 
 // stateJumpStage denotes the stage of state jump process.
@@ -504,34 +498,18 @@ func (bc *Blockchain) jumpToStateInternal(p uint32, stage stateJumpStage) error
 		}
 		fallthrough
 	case oldStorageItemsRemoved:
-		// Then change STTempStorage prefix to STStorage. Each replace operation is atomic.
-		for {
-			count := 0
-			b := bc.dao.Store.Batch()
-			currPrefix := byte(bc.dao.StoragePrefix)
-			syncPrefix := byte(statesync.TemporaryPrefix(bc.dao.StoragePrefix))
-			bc.dao.Store.Seek([]byte{syncPrefix}, func(k, v []byte) {
-				if count >= maxStorageBatchSize {
-					return
-				}
-				// #1468, but don't need to copy here, because it is done by Store.
-				b.Delete(k)
-				key := make([]byte, len(k))
-				key[0] = currPrefix
-				copy(key[1:], k[1:])
-				b.Put(key, slice.Copy(v))
-				count += 2
-			})
-			if count > 0 {
-				err := bc.dao.Store.PutBatch(b)
+		newPrefix := statesync.TemporaryPrefix(bc.dao.StoragePrefix)
+		v, err := bc.dao.GetVersion()
 		if err != nil {
-					return fmt.Errorf("failed to replace outdated contract storage items with the fresh ones: %w", err)
+			return fmt.Errorf("failed to get dao.Version: %w", err)
 		}
-			} else {
-				break
+		v.Prefix = newPrefix
+		if err := bc.dao.PutVersion(v); err != nil {
+			return fmt.Errorf("failed to update dao.Version: %w", err)
 		}
-		}
-		err := bc.dao.Store.Put(jumpStageKey, []byte{byte(newStorageItemsAdded)})
+		bc.persistent.StoragePrefix = newPrefix
+
+		err = bc.dao.Store.Put(jumpStageKey, []byte{byte(newStorageItemsAdded)})
 		if err != nil {
 			return fmt.Errorf("failed to store state jump stage: %w", err)
 		}

pkg/core/mpt/billet.go

@@ -66,6 +66,9 @@ func (b *Billet) RestoreHashNode(path []byte, node Node) error {
 
 	// If it's a leaf, then put into temporary contract storage.
 	if leaf, ok := node.(*LeafNode); ok {
+		if b.TempStoragePrefix == 0 {
+			panic("invalid storage prefix")
+		}
 		k := append([]byte{byte(b.TempStoragePrefix)}, fromNibbles(path)...)
 		_ = b.Store.Put(k, leaf.value)
 	}

pkg/core/statesync_test.go

@@ -300,7 +300,9 @@ func TestStateSyncModule_RestoreBasicChain(t *testing.T) {
 		c.ProtocolConfiguration.KeepOnlyLatestState = true
 		c.ProtocolConfiguration.RemoveUntraceableBlocks = true
 	}
-	bcBolt := newTestChainWithCustomCfg(t, boltCfg)
+	bcBoltStore := memoryStore{storage.NewMemoryStore()}
+	bcBolt := initTestChain(t, bcBoltStore, boltCfg)
+	go bcBolt.Run()
 	module := bcBolt.GetStateSyncModule()
 
 	t.Run("error: add headers before initialisation", func(t *testing.T) {
@@ -424,6 +426,9 @@ func TestStateSyncModule_RestoreBasicChain(t *testing.T) {
 		bc.dao.Store.Seek(bc.dao.StoragePrefix.Bytes(), func(k, v []byte) {
 			key := slice.Copy(k)
 			value := slice.Copy(v)
+			if key[0] == byte(storage.STTempStorage) {
+				key[0] = byte(storage.STStorage)
+			}
 			kv = append(kv, storage.KeyValue{
 				Key:   key,
 				Value: value,
@@ -436,7 +441,15 @@ func TestStateSyncModule_RestoreBasicChain(t *testing.T) {
 	require.ElementsMatch(t, expected, actual)
 
 	// no temp items should be left
-	bcBolt.dao.Store.Seek(storage.STTempStorage.Bytes(), func(k, v []byte) {
+	bcBolt.dao.Store.Seek(storage.STStorage.Bytes(), func(k, v []byte) {
 		t.Fatal("temp storage items are found")
 	})
+	bcBolt.Close()
+
+	// Check restoring with new prefix.
+	bcBolt = initTestChain(t, bcBoltStore, boltCfg)
+	go bcBolt.Run()
+	defer bcBolt.Close()
+	require.Equal(t, storage.STTempStorage, bcBolt.dao.StoragePrefix)
+	require.Equal(t, storage.STTempStorage, bcBolt.persistent.StoragePrefix)
 }