Deadlocks

Scenarios

RDS for SQL Server provides powerful deadlock detection. If there are two or more processes accessing the same resource at the same time, a deadlock may occur because the processes are waiting for each other to release the resource and cannot continue running. In this case, RDS for SQL Server kills one of the processes so that the other processes can complete their transactions.

To solve this problem, the Deadlocks page is provided. On this page, you can quickly locate various types of deadlocks in your instance. The Details area displays information such as transaction start time, session ID, locked resource details, and deadlock mode, helping you locate and optimize problematic SQL statements and other exceptions.

If Intelligent O&M is not subscribed, records of a maximum of seven days can be retained.

Procedure

1. Log in to the management console.
2. Click in the upper left corner and select a region.
3. Click in the upper left corner of the page and choose Databases > Relational Database Service.
4. On the Instances page, click the DB instance name.
5. In the navigation pane, choose DBA Assistant > Historical Diagnosis.
6. Click the Deadlocks tab.
   • Deadlocks

     You can view the number of deadlocks in the last day, last week, last two weeks, last month, or in a custom time interval.

   • Deadlocks over Time

     You can view deadlocks over time within a specified period.

     Table 1 Parameter description

     Parameter	Description
     Total	Total number of deadlocks.
     Key Lock	Number of index-related deadlocks.
     Object Lock	Number of object-related deadlocks.
     Rid Lock	Number of row deadlocks.
     Page Lock	Number of page deadlocks.
     Compile Lock	Number of compilation deadlocks.

     • Details

       You can view details of deadlocks within a specified period.

       To view the deadlock relationship diagram, click Deadlock Diagram in the Operation column. In the displayed dialog box, you can click Download to download the diagram.

       

       The downloaded deadlock diagram is an XDL file. You can open and check it using the SQL Server Management Studio (SSMS) client.

       Table 2 Parameter description

       Parameter	Description
       LastTranStarted	Start time of the transaction.
       SPID	ID of the session that starts the transaction.
       isVictim	Whether the session is killed.
       Database	Name of the database where the transaction is executed.
       LogUsed	Size of logs that have been generated for the session, in bytes.
       LockMode	Lock mode.
       WaitResourceDesc	Details of the resource that the transaction is waiting for.
       ObjectOwned	Locked object.
       ObjectRequested	Object that the transaction requests to lock.
       WaitResource	Resource that the transaction is waiting for.
       HostName	Name of the host on which the transaction is run.
       LoginName	Username of the account that is used to run the transaction.
       Status	Transaction status.
       ClientApp	Name of the client that initiates the transaction.
       SQL	SQL statement details.
       Operation	You can view the deadlock diagram.