fix bug

connection.go

@@ -733,7 +733,7 @@ func (stmt *mysqlStmt) ExecContext(ctx context.Context, args []driver.NamedValue
 	return stmt.Exec(dargs)
 }
 
-func executable(mc *mysqlConn, sql string, args []driver.Value) (bool,error) {
+func executable(mc *mysqlConn, sql string, args []driver.Value) (bool, error) {
 	parser := parser.New()
 	act, _ := parser.ParseOneStmt(sql, "", "")
 	deleteStmt, isDelete := act.(*ast.DeleteStmt)

executor.go

@@ -265,7 +265,7 @@ func (executor *deleteExecutor) Execute() (driver.Result, error) {
 }
 
 func (executor *deleteExecutor) PrepareUndoLog(beforeImage, afterImage *schema.TableRecords) {
-	if len(beforeImage.Rows) == 0 {
+	if beforeImage == nil || len(beforeImage.Rows) == 0 {
 		return
 	}
 
@@ -379,7 +379,7 @@ func (executor *updateExecutor) Execute() (driver.Result, error) {
 }
 
 func (executor *updateExecutor) PrepareUndoLog(beforeImage, afterImage *schema.TableRecords) {
-	if len(beforeImage.Rows) == 0 &&
+	if (beforeImage == nil || len(beforeImage.Rows) == 0) &&
 		(afterImage == nil || len(afterImage.Rows) == 0) {
 		return
 	}
@@ -402,7 +402,7 @@ func (executor *updateExecutor) BeforeImage() (*schema.TableRecords, error) {
 }
 
 func (executor *updateExecutor) AfterImage(beforeImage *schema.TableRecords) (*schema.TableRecords, error) {
-	if beforeImage.Rows == nil || len(beforeImage.Rows) == 0 {
+	if beforeImage == nil || len(beforeImage.Rows) == 0 {
 		return nil, nil
 	}
 
@@ -553,7 +553,7 @@ func (executor *globalLockExecutor) Executable(lockRetryInterval time.Duration,
 		var err error
 		for i := 0; i < lockRetryTimes; i++ {
 			lockable, err = rm.GetResourceManager().LockQuery(context.Background(),
-				"", executor.mc.cfg.DBName, apis.AT, lockKeys )
+				"", executor.mc.cfg.DBName, apis.AT, lockKeys)
 			if lockable && err == nil {
 				return true, nil
 			}
@@ -648,4 +648,4 @@ func buildRecords(meta schema.TableMeta, rows driver.Rows) *schema.TableRecords
 	}
 	records.Rows = rs
 	return records
-}
+}