Problem: redundant copy in check validate (#1502)

free key

update doc

cleanup

CHANGELOG.md

@@ -6,6 +6,7 @@
 
 * (versiondb) [#1379](https://github.com/crypto-org-chain/cronos/pull/1379) Flush versiondb when graceful shutdown, make rocksdb upgrade smooth.
 * (versiondb) [#1491](https://github.com/crypto-org-chain/cronos/pull/1491) Free slice data in HasAtVersion.
+* (versiondb) [#1498](https://github.com/crypto-org-chain/cronos/pull/1498) Reduce scope of copying slice data in iterator.
 
 ### Bug Fixes
 

versiondb/tsrocksdb/iterator.go

@@ -23,8 +23,9 @@ func newRocksDBIterator(source *grocksdb.Iterator, prefix, start, end []byte, is
 		} else {
 			source.Seek(end)
 			if source.Valid() {
-				eoakey := moveSliceToBytes(source.Key()) // end or after key
-				if bytes.Compare(end, eoakey) <= 0 {
+				eoakey := source.Key() // end or after key
+				defer eoakey.Free()
+				if bytes.Compare(end, eoakey.Data()) <= 0 {
 					source.Prev()
 				}
 			} else {
@@ -75,14 +76,15 @@ func (itr *rocksDBIterator) Valid() bool {
 	// If key is end or past it, invalid.
 	start := itr.start
 	end := itr.end
-	key := moveSliceToBytes(itr.source.Key())
+	key := itr.source.Key()
+	defer key.Free()
 	if itr.isReverse {
-		if start != nil && bytes.Compare(key, start) < 0 {
+		if start != nil && bytes.Compare(key.Data(), start) < 0 {
 			itr.isInvalid = true
 			return false
 		}
 	} else {
-		if end != nil && bytes.Compare(end, key) <= 0 {
+		if end != nil && bytes.Compare(end, key.Data()) <= 0 {
 			itr.isInvalid = true
 			return false
 		}