sql put kv: avoid unnecessary update

weed/filer/abstract_sql/abstract_sql_store_kv.go

@@ -5,11 +5,10 @@ import (
 	"database/sql"
 	"encoding/base64"
 	"fmt"
-	"strings"
-
 	"github.com/chrislusf/seaweedfs/weed/filer"
 	"github.com/chrislusf/seaweedfs/weed/glog"
 	"github.com/chrislusf/seaweedfs/weed/util"
+	"strings"
 )
 
 func (store *AbstractSqlStore) KvPut(ctx context.Context, key []byte, value []byte) (err error) {
@@ -17,11 +16,13 @@ func (store *AbstractSqlStore) KvPut(ctx context.Context, key []byte, value []by
 	dirStr, dirHash, name := genDirAndName(key)
 
 	res, err := store.getTxOrDB(ctx).ExecContext(ctx, store.SqlInsert, dirHash, name, dirStr, value)
-	if err != nil {
+	if err == nil {
+		return
+	}
+
 	if !strings.Contains(strings.ToLower(err.Error()), "duplicate") {
 		return fmt.Errorf("kv insert: %s", err)
 	}
-	}
 
 	// now the insert failed possibly due to duplication constraints
 	glog.V(1).Infof("kv insert falls back to update: %s", err)