On the Events Extraction Setting stab, click Save Deadlock XML Events Separately.The Events Extraction Settings tab is added to the Trace Properties dialog box. If the Locks event category is not available, check Show all events to display it. In the Events data column, expand the Locks event category, and then select the Deadlock graph check box.Optionally, select the Enable trace stop time check box, and specify a stop date and time.Optionally, click Set maximum rows, and specify a value. Select the Save to table check box to capture the trace to a database table.Optionally, select Enable file rollover and Server processes trace data. Specify a value for Set maximum file size. Select the Save to file check box to capture the trace to a file.In the Use the template list, select a trace template on which to base the trace, or select Blank if you do not want to use a template.In the Trace Properties dialog box, type a name for the trace in the Trace name box.On the File menu, click New Trace, and then connect to an instance of SQL Server.) AS recurso ON recurso.resourceProcessOwner = 'varchar(100)') AND recurso.Dt_Evento = A.How to save deadlock graph events as. OUTER APPLY ('owner-list/owner') AS owner(dados) LEFT JOIN 'int') AS 'int') AS 'int') AS 'varchar(128)') AS 'varchar(2)') AS 'varchar(128)') AS 'varchar(2)') AS ĬROSS APPLY A.TargetData.nodes('//ridlock') AS recurso(dados) OUTER APPLY dados.event_data.nodes('data/value/deadlock/process-list/process') AS processo(dados) ('(inputbuf/text())') AS ,ĭB_NAME(recurso.resourceDBId) AS 'varchar(100)') AS 'int') AS 'varchar(60)') AS 'varchar(60)') AS 'int') AS 'varchar(256)') AS 'varchar(256)') AS 'varchar(256)') AS 'varchar(256)') AS 'varchar(256)') AS 'varchar(256)')) AS 'int') AS 'varchar(10)') AS ,ĬROSS APPLY A.TargetData.nodes('//event') AS dados(event_data)ĬROSS APPLY dados.event_data.nodes('data/value/deadlock/victim-list/victimProcess') AS vitima(dados) Sys.fn_xe_file_target_read_file(N'C:\Logs\Deadlocks*.xel', NULL, NULL, NULL)ĭATEADD(HOUR, 'datetime2')) AS , IF (OBJECT_ID('tempdb.#xml_deadlock') IS NOT NULL) DROP TABLE #xml_deadlockĭATEADD(HOUR, CAST(timestamp_utc AS DATETIME2)) AS Dt_Evento, DATETIME2 = ISNULL((SELECT MAX(Dt_Log) FROM dbo.Historico_Deadlocks WITH(NOLOCK)), INT = DATEDIFF(HOUR, GETUTCDATE(), GETDATE()) IF (OBJECT_ID('dbo.Historico_Deadlocks') IS NULL) Passo 5 - Vou tentar travar a Tabela (já possui lock na outra sessão) Passo 6 - Ao tentar travar a Tabela 1, irá ocorrer o deadlock If there are still deadlocks in the instance, it will eliminate more sessions and shorten the next execution cycles in 100ms (each cycle) until no deadlock is detected. When the Deadlock Monitor Thread drops a session due to deadlock, it runs again immediately to verify that the deadlock has been resolved. If the sessions have the same priority and the same cost, the victim of the deadlock will be chosen at random. How does SQL Server decide which session it will drop? It is very simple, it will always eliminate the session that has the lowest cost (generally, the one that was “locked” last), thus facilitating the rollback of transactions performed by the session that was chosen to be disconnected (deadlock victim) As long as they have the same priority. If it encounters any deadlock, it will kill one of the deadlocked sessions to free the locked resources for the other waiting session. This thread fires every 5 seconds to check for deadlocks on the instance. If you query the sys.dm_os_waiting_tasks DMV, you will notice that there is always a system task with the REQUEST_FOR_DEADLOCK_SEARCH event. In SQL Server there is a feature called Deadlock Monitor Thread, which runs in the background to identify and “help” resolve deadlocks in the instance, thus preventing the sessions from endlessly waiting for each other.
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