小编dew*_*wet的帖子

我创建了一个扩展事件会话，我想在其中查看使用 nolock 提示的所有查询。我决定使用它而不是 sql trace 来最小化可能的性能影响。会话的创建类似于以下语句：

    CREATE EVENT SESSION [SCOMDB_debug] ON SERVER 
    ADD EVENT sqlserver.deprecation_announcement(
        ACTION(sqlserver.client_hostname,sqlserver.database_name,sqlserver.nt_username,sqlserver.session_id,sqlserver.sql_text,sqlserver.transaction_id,sqlserver.username)),
    ADD EVENT sqlserver.rpc_completed(
        ACTION(sqlserver.client_hostname,sqlserver.database_name,sqlserver.nt_username,sqlserver.session_id,sqlserver.sql_text,sqlserver.transaction_id,sqlserver.username)
        WHERE ([sqlserver].[like_i_sql_unicode_string]([sqlserver].[sql_text],N'%NOLOCK%'))),
    ADD EVENT sqlserver.rpc_starting(
        ACTION(sqlserver.client_hostname,sqlserver.database_name,sqlserver.nt_username,sqlserver.session_id,sqlserver.sql_text,sqlserver.transaction_id,sqlserver.username)
        WHERE ([sqlserver].[like_i_sql_unicode_string]([sqlserver].[sql_text],N'%NOLOCK%'))),
    ADD EVENT sqlserver.sp_statement_completed(
        ACTION(sqlserver.client_hostname,sqlserver.database_name,sqlserver.nt_username,sqlserver.session_id,sqlserver.sql_text,sqlserver.transaction_id,sqlserver.username)
        WHERE ([sqlserver].[like_i_sql_unicode_string]([sqlserver].[sql_text],N'%NOLOCK%'))),
    ADD EVENT sqlserver.sp_statement_starting(
        ACTION(sqlserver.client_hostname,sqlserver.database_name,sqlserver.nt_username,sqlserver.session_id,sqlserver.sql_text,sqlserver.transaction_id,sqlserver.username)
        WHERE ([sqlserver].[like_i_sql_unicode_string]([sqlserver].[sql_text],N'%NOLOCK%'))),
    ADD EVENT sqlserver.sql_batch_completed(
        ACTION(sqlserver.client_hostname,sqlserver.database_name,sqlserver.nt_username,sqlserver.session_id,sqlserver.sql_text,sqlserver.transaction_id,sqlserver.username)
        WHERE ([sqlserver].[like_i_sql_unicode_string]([sqlserver].[sql_text],N'%NOLOCK%'))),
    ADD EVENT sqlserver.sql_batch_starting(
        ACTION(sqlserver.client_hostname,sqlserver.database_name,sqlserver.nt_username,sqlserver.session_id,sqlserver.sql_text,sqlserver.transaction_id,sqlserver.username)
        WHERE ([sqlserver].[like_i_sql_unicode_string]([sqlserver].[sql_text],N'%NOLOCK%'))),
    ADD EVENT sqlserver.sql_statement_completed(
        ACTION(sqlserver.client_hostname,sqlserver.database_name,sqlserver.nt_username,sqlserver.session_id,sqlserver.sql_text,sqlserver.transaction_id,sqlserver.username)
        WHERE ([sqlserver].[like_i_sql_unicode_string]([sqlserver].[sql_text],N'%NOLOCK%'))),
    ADD EVENT sqlserver.sql_statement_starting(SET collect_statement=(1)
        ACTION(sqlserver.client_hostname,sqlserver.database_name,sqlserver.nt_username,sqlserver.session_id,sqlserver.sql_text,sqlserver.transaction_id,sqlserver.username)
        WHERE ([sqlserver].[like_i_sql_unicode_string]([sqlserver].[sql_text],N'%NOLOCK%'))) 
    ADD TARGET package0.event_file(SET filename=N'M:\MSSQL11.SCOMDB\MSSQL\Log\SCOMDB_debug.xel',max_file_size=(500))
    WITH (MAX_MEMORY=40960 KB,EVENT_RETENTION_MODE=ALLOW_SINGLE_EVENT_LOSS,MAX_DISPATCH_LATENCY=30 SECONDS,MAX_EVENT_SIZE=0 KB,MEMORY_PARTITION_MODE=NONE,TRACK_CAUSALITY=OFF,STARTUP_STATE=OFF)
    GO

结果是数据库实例（用于 SCOM 数据库）变得非常缓慢，应用程序几乎无法使用。

等待统计信息中充满了 SOS_SCHEDULER_YIELD …

我想测试 tempdb 溢出警告，所以我在 SQL Server 2014 上运行以下脚本：

USE tempdb

IF OBJECT_ID('tempdb..tblTest') IS NOT NULL DROP TABLE tblTest

CREATE TABLE tblTest
(
          c1 INT         PRIMARY KEY CLUSTERED,
          c2 INT        ,
          c3 CHAR (1000)
);

GO
SET NOCOUNT ON;

BEGIN TRANSACTION;

DECLARE @i AS INT;

SET @i = 1;

WHILE @i <= 10000
          BEGIN
                    INSERT  INTO tblTest (c1, c2, c3)
                    VALUES              (@i, @i, 'a');
                    SET @i = @i + 1;
          END

COMMIT TRANSACTION;

GO
UPDATE STATISTICS dbo.tblTest
GO
SET STATISTICS XML ON; …