diff --git a/core/blockchain.go b/core/blockchain.go
index 1f978ea485..b40f853db5 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -2233,28 +2233,28 @@ func (bc *BlockChain) insertChain(chain types.Blocks, setHead bool) (int, error)
 		}
 		log.Info("+++++++++++++start block", "number", block.NumberU64())
 		defer log.Info("+++++++++++++end block", "number", block.NumberU64())
-		statedb, err := state.NewWithSharedPool(parent.Root, bc.stateCache, bc.snaps)
+		statedb, err := state.NewWithSharedPool(parent.Root, bc.stateCache, nil)
 		if err != nil {
 			return it.index, err
 		}
 		bc.updateHighestVerifiedHeader(block.Header())
 
 		// Enable prefetching to pull in trie node paths while processing transactions
-		statedb.StartPrefetcher("chain")
+		//statedb.StartPrefetcher("chain")
 		interruptCh := make(chan struct{})
 		// For diff sync, it may fallback to full sync, so we still do prefetch
-		if len(block.Transactions()) >= prefetchTxNumber {
-			// do Prefetch in a separate goroutine to avoid blocking the critical path
-
-			// 1.do state prefetch for snapshot cache
-			throwaway := statedb.CopyDoPrefetch()
-			go bc.prefetcher.Prefetch(block, throwaway, &bc.vmConfig, interruptCh)
-
-			// 2.do trie prefetch for MPT trie node cache
-			// it is for the big state trie tree, prefetch based on transaction's From/To address.
-			// trie prefetcher is thread safe now, ok to prefetch in a separate routine
-			go throwaway.TriePrefetchInAdvance(block, signer)
-		}
+		//if len(block.Transactions()) >= prefetchTxNumber {
+		//	// do Prefetch in a separate goroutine to avoid blocking the critical path
+		//
+		//	// 1.do state prefetch for snapshot cache
+		//	throwaway := statedb.CopyDoPrefetch()
+		//	go bc.prefetcher.Prefetch(block, throwaway, &bc.vmConfig, interruptCh)
+		//
+		//	// 2.do trie prefetch for MPT trie node cache
+		//	// it is for the big state trie tree, prefetch based on transaction's From/To address.
+		//	// trie prefetcher is thread safe now, ok to prefetch in a separate routine
+		//	go throwaway.TriePrefetchInAdvance(block, signer)
+		//}
 
 		// Process block using the parent state as reference point
 		if bc.pipeCommit {
diff --git a/core/state/statedb.go b/core/state/statedb.go
index dd6ce9443a..1c34b7fcee 100644
--- a/core/state/statedb.go
+++ b/core/state/statedb.go
@@ -172,6 +172,7 @@ func NewWithSharedPool(root common.Hash, db Database, snaps *snapshot.Tree) (*St
 
 // New creates a new state from a given trie.
 func New(root common.Hash, db Database, snaps *snapshot.Tree) (*StateDB, error) {
+	snaps = nil
 	sdb := &StateDB{
 		db:                   db,
 		originalRoot:         root,
@@ -222,6 +223,9 @@ func (s *StateDB) TransferPrefetcher(prev *StateDB) {
 	prev.prefetcherLock.Lock()
 	fetcher = prev.prefetcher
 	prev.prefetcher = nil
+	if fetcher != nil {
+		panic("TransferPrefetcher")
+	}
 	prev.prefetcherLock.Unlock()
 
 	s.prefetcherLock.Lock()
@@ -243,6 +247,7 @@ func (s *StateDB) StartPrefetcher(namespace string) {
 		s.prefetcher = nil
 	}
 	if s.snap != nil {
+		panic("StartPrefetcher")
 		parent := s.snap.Parent()
 		if parent != nil {
 			s.prefetcher = newTriePrefetcher(s.db, s.originalRoot, parent.Root(), namespace)
diff --git a/eth/backend.go b/eth/backend.go
index aa0b90e49c..986e8a467d 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -270,7 +270,7 @@ func New(stack *node.Node, config *ethconfig.Config) (*Ethereum, error) {
 			TrieDirtyDisabled:   config.NoPruning,
 			TrieTimeLimit:       config.TrieTimeout,
 			NoTries:             config.TriesVerifyMode != core.LocalVerify,
-			SnapshotLimit:       config.SnapshotCache,
+			SnapshotLimit:       0, // forbid snapshot
 			TriesInMemory:       config.TriesInMemory,
 			Preimages:           config.Preimages,
 			StateHistory:        config.StateHistory,
diff --git a/trie/secure_trie.go b/trie/secure_trie.go
index 5462f6eb7e..7157531fd1 100644
--- a/trie/secure_trie.go
+++ b/trie/secure_trie.go
@@ -19,6 +19,7 @@ package trie
 import (
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/rlp"
 	"github.com/ethereum/go-ethereum/trie/trienode"
 	"github.com/ethereum/go-ethereum/triedb/database"
@@ -86,12 +87,13 @@ func (t *StateTrie) MustGet(key []byte) []byte {
 // and slot key. The value bytes must not be modified by the caller.
 // If the specified storage slot is not in the trie, nil will be returned.
 // If a trie node is not found in the database, a MissingNodeError is returned.
-func (t *StateTrie) GetStorage(_ common.Address, key []byte) ([]byte, error) {
+func (t *StateTrie) GetStorage(addr common.Address, key []byte) ([]byte, error) {
 	enc, err := t.trie.Get(t.hashKey(key))
 	if err != nil || len(enc) == 0 {
 		return nil, err
 	}
 	_, content, _, err := rlp.Split(enc)
+	log.Info("get storage", "owner", addr.String(), "key", common.Bytes2Hex(key), "val", common.Bytes2Hex(content))
 	return content, err
 }
 
@@ -105,6 +107,7 @@ func (t *StateTrie) GetAccount(address common.Address) (*types.StateAccount, err
 	}
 	ret := new(types.StateAccount)
 	err = rlp.DecodeBytes(res, ret)
+	log.Info("get account", "addr", address.String(), "nonce", ret.Nonce, "balance", ret.Balance, "root", ret.Root.String(), "code", common.Bytes2Hex(ret.CodeHash))
 	return ret, err
 }