diff --git a/cmd/utils/flags.go b/cmd/utils/flags.go
index fd8c2cbb30..8739d49899 100644
--- a/cmd/utils/flags.go
+++ b/cmd/utils/flags.go
@@ -1727,7 +1727,11 @@ func MakeChain(ctx *cli.Context, stack *node.Node) (chain *core.BlockChain, chai
 		cache.TrieDirtyLimit = ctx.GlobalInt(CacheFlag.Name) * ctx.GlobalInt(CacheGCFlag.Name) / 100
 	}
 	vmcfg := vm.Config{EnablePreimageRecording: ctx.GlobalBool(VMEnableDebugFlag.Name)}
-	chain, err = core.NewBlockChain(chainDb, cache, config, engine, vmcfg, nil, 0)
+	txLookupLimit := uint64(0)
+	if ctx.GlobalIsSet(TxLookupLimitFlag.Name) {
+		txLookupLimit = ctx.GlobalUint64(TxLookupLimitFlag.Name)
+	}
+	chain, err = core.NewBlockChain(chainDb, cache, config, engine, vmcfg, nil, txLookupLimit)
 	if err != nil {
 		Fatalf("Can't create BlockChain: %v", err)
 	}
diff --git a/core/blockchain.go b/core/blockchain.go
index e86f1242de..9f9fec0936 100644
--- a/core/blockchain.go
+++ b/core/blockchain.go
@@ -2074,10 +2074,15 @@ func (bc *BlockChain) update() {
 func (bc *BlockChain) maintainTxIndex() {
 	// initialiseIndices inits tx indices into the database if `TxIndexTail`
 	// is missing in database.
-	// Note for archive sync or fast sync, this code path will only be triggered
+	//
+	// Note for archive sync or full sync, this code path will only be triggered
 	// after importing the first batch of blocks(e.g. 1024). But these block
 	// actually are already indexed. So a binary search will be performed to
 	// skip reindexing.
+	//
+	// Besides for old node database which actually contains all indices but
+	// without `TxIndexTail` in database, binary search can also help to skip
+	// reindexing.
 	initialiseIndices := func(head uint64, done chan struct{}) {
 		defer func() { done <- struct{}{} }()
 
diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go
index 255f553db4..fa0d3f2340 100644
--- a/eth/downloader/downloader.go
+++ b/eth/downloader/downloader.go
@@ -1721,7 +1721,7 @@ func (d *Downloader) commitPivotBlock(result *fetchResult) error {
 	if _, err := d.blockchain.InsertReceiptChain([]*types.Block{block}, []types.Receipts{result.Receipts}, d.ancientLimit); err != nil {
 		return err
 	}
-	// Use origin block number + 1 as the number of the first inserted block.
+	// Use origin block number + 1 as the first inserted block number
 	d.syncStatsLock.RLock()
 	from := d.syncStatsChainOrigin + 1
 	d.syncStatsLock.RUnlock()