Online DDL: fix defer function, potential connection pool exhaustion (#17207)

vitess-bot[bot] · vitess-bot · commit e8357f65bb7f · 2024-11-11T10:48:43.000Z
Signed-off-by: Shlomi Noach &lt;2607934+shlomi-noach@users.noreply.github.com&gt;
diff --git a/go/vt/vttablet/onlineddl/executor.go b/go/vt/vttablet/onlineddl/executor.go
@@ -963,13 +963,13 @@ func (e *Executor) cutOverVReplMigration(ctx context.Context, s *VReplStream, sh
 	if err != nil {
 		return err
 	}
+	defer lockConn.Recycle()
 	// Set large enough `@@lock_wait_timeout` so that it does not interfere with the cut-over operation.
 	// The code will ensure everything that needs to be terminated by `migrationCutOverThreshold` will be terminated.
 	lockConnRestoreLockWaitTimeout, err := e.initConnectionLockWaitTimeout(ctx, lockConn.Conn, 5*migrationCutOverThreshold)
 	if err != nil {
 		return err
 	}
-	defer lockConn.Recycle()
 	defer lockConnRestoreLockWaitTimeout()
 	defer lockConn.Conn.Exec(ctx, sqlUnlockTables, 1, false)
 

Original file line number	Diff line number	Diff line change
`@@ -963,13 +963,13 @@ func (e Executor) cutOverVReplMigration(ctx context.Context, s VReplStream, sh`
`963`	`963`	`if err != nil {`
`964`	`964`	`return err`
`965`	`965`	`}`
	`966`	`+ defer lockConn.Recycle()`
`966`	`967`	// Set large enough `@@lock_wait_timeout` so that it does not interfere with the cut-over operation.
`967`	`968`	// The code will ensure everything that needs to be terminated by `migrationCutOverThreshold` will be terminated.
`968`	`969`	`lockConnRestoreLockWaitTimeout, err := e.initConnectionLockWaitTimeout(ctx, lockConn.Conn, 5*migrationCutOverThreshold)`
`969`	`970`	`if err != nil {`
`970`	`971`	`return err`
`971`	`972`	`}`
`972`		`- defer lockConn.Recycle()`
`973`	`973`	`defer lockConnRestoreLockWaitTimeout()`
`974`	`974`	`defer lockConn.Conn.Exec(ctx, sqlUnlockTables, 1, false)`
`975`	`975`