【1】报错信息
运行删除时报错
操作的删除语句：
IF OBJECT_ID('tempdb..#temp_Robot') IS NOT NULL DROP TABLE #temp_Robot CREATE TABLE #temp_Robot(UserID INT NOT NULL PRIMARY KEY) select * from #temp_robot INSERT INTO #temp_Robot SELECT UserID FROM Db_Tank..Sys_Users_Order WHERE IsRobot IN (1,3) DELETE FROM #temp_Robot WHERE UserID IN (SELECT UserID FROM Db_Tank..Sys_Users_Detail WHERE ConsortiaID>0)
--核心语句在这里 DELETE Db_Tank..Sys_Users_History WHERE UserID IN (SELECT UserID FROM #temp_Robot)
报错信息：
Location: lckmgr.cpp:9421 Expression: NULL == m_lockList.Head () SPID: 56 Process ID: 5972 Location: "xact.cpp":2630 Expression: !m_updNestedXactCnt SPID: 56 Process ID: 5972 Description: Trying to use the transaction while there are 1 parallel nested xacts outstanding Location: "xact.cpp":2788 Expression: !m_updNestedXactCnt SPID: 56 Process ID: 5972 Description: Trying to use the transaction while there are 1 parallel nested xacts outstanding Location: "xact.cpp":3851 Expression: !m_parNestedXactCnt SPID: 56 Process ID: 5972 Description: Trying to use the transaction while there are 7 parallel nested xacts outstanding Location: "xact.cpp":2879 Expression: !m_updNestedXactCnt SPID: 56 Process ID: 5972 Description: Trying to use the transaction while there are 1 parallel nested xacts outstanding 消息 3624，级别 20，状态 1，第 1 行 系统断定检查已失败。有关详细信息，请查看 SQL Server 错误日志 消息 0，级别 20，状态 0，第 0 行 当前命令发生了严重错误。应放弃任何可能产生的结果。
系统日志报错：
【2】排查办法
（1）使用select count(1) from Db_Tank..Sys_Users_History
发现也是卡顿，连查询都不能查，明显有问题啊。count(1) 探索的是聚集索引列
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（2）查看表结构 sp_help Sys_Users_History
只有一个userid的聚集索引，正好我们删除也是用它来关联的。估计问题就出在这里了。
当然，这只是经验之谈，如果没什么经验的朋友建议运行DBCC CHECKDB 检查一下这个库。
【3】解决办法，重建索引
use db_tank go alter index PK_Sys_Users_History on Sys_Users_History rebuild
OK，搞定！
【4】总结
出了问题不要慌，要想办法定位原因，然后得以解决