minor cleanup

go/logic/applier.go

@@ -199,41 +199,15 @@ func (this *Applier) ValidateOrDropExistingTables() error {
 // It is safer to attempt the change than try and parse the DDL, since
 // there might be specifics about the table which make it not possible to apply instantly.
 func (this *Applier) AttemptInstantDDL() error {
-
 	query := fmt.Sprintf(`ALTER /* gh-ost */ TABLE %s.%s %s, ALGORITHM=INSTANT`,
 		sql.EscapeName(this.migrationContext.DatabaseName),
 		sql.EscapeName(this.migrationContext.OriginalTableName),
 		this.migrationContext.AlterStatementOptions,
 	)
-	this.migrationContext.Log.Infof("INSTANT DDL Query is: %s", query)
-
-	err := func() error {
-		tx, err := this.db.Begin()
-		if err != nil {
-			return err
-		}
-		defer tx.Rollback()
-
-		sessionQuery := fmt.Sprintf(`SET SESSION time_zone = '%s'`, this.migrationContext.ApplierTimeZone)
-		sessionQuery = fmt.Sprintf("%s, %s", sessionQuery, this.generateSqlModeQuery())
-
-		if _, err := tx.Exec(sessionQuery); err != nil {
-			return err
-		}
-		if _, err := tx.Exec(query); err != nil {
-			this.migrationContext.Log.Infof("INSTANT DDL failed: %s", err)
-			return err
-		}
-		if err := tx.Commit(); err != nil {
-			// Neither SET SESSION nor ALTER are really transactional, so strictly speaking
-			// there's no need to commit; but let's do this the legit way anyway.
-			return err
-		}
-		return nil
-	}()
-
+	this.migrationContext.Log.Infof("INSTANT DDL query is: %s", query)
+	// We don't need a trx, because for instant DDL the SQL mode doesn't matter.
+	_, err := this.db.Exec(query)
 	return err
-
 }
 
 // CreateGhostTable creates the ghost table on the applier host

go/logic/migrator.go

@@ -370,7 +370,6 @@ func (this *Migrator) Migrate() (err error) {
 	if err := this.initiateApplier(); err != nil {
 		return err
 	}
-
 	if err := this.createFlagFiles(); err != nil {
 		return err
 	}