INSERT 和 SELECT SP 之间的死锁

Posted 2023-03-22

【中文标题】INSERT 和 SELECT SP 之间的死锁

【英文标题】：Deadlock between INSERT and SELECT SPs

【发布时间】：2014-03-19 13:27:57

【问题描述】：

我遇到了一个应用程序问题，我遇到了我认为永远不会发生的死锁。我有两个存储过程。其中一个只是读取表的一部分，其中一个在表中添加一行，或者如果存在主键冲突，则更新现有行。

我已经阅读了有关存储过程可以获得共享读锁的信息，如果两个存储过程都升级为排他锁，则会出现死锁。我在这里看不到这种情况，因为 GetList 存储过程只是读取而从不写入。这些存储过程死锁还有其他可能的原因吗？

以下关于死锁的报告：

<?xml version="1.0" encoding="UTF-8"?>
<deadlock-list>
   <deadlock victim="process3e37f62c8">
      <process-list>
         <process id="process3e37f62c8" taskpriority="0" logused="0" waitresource="KEY: 7:72057594152681472 (de2613e7782e)" waittime="2535" ownerId="7732055781" transactionname="SELECT" lasttranstarted="2014-03-17T17:48:31.437" XDES="0x1298bc1c0" lockMode="S" schedulerid="11" kpid="21372" status="suspended" spid="121" sbid="0" ecid="0" priority="0" trancount="0" lastbatchstarted="2014-03-17T17:48:31.437" lastbatchcompleted="2014-03-17T17:48:31.437" clientapp=".Net SqlClient Data Provider" hostname="STO2AP07" hostpid="4908" loginname="(hidden)" isolationlevel="read committed (2)" xactid="7732055781" currentdb="7" lockTimeout="4294967295" clientoption1="673185824" clientoption2="128056">
            <executionStack>
               <frame procname="(hidden).dbo.GetList" line="18" stmtstart="1060" stmtend="1942" sqlhandle="0x03000700072cfd1b7b8be800cfa200000100000000000000">
                   SELECT 
                        TOP (@NumRows)
                        [T1].[Id] , 
                        [T1].[A] , 
                        [T1].[B] , 
                        [T1].[C] , 
                        [T1].[D] , 
                        [T1].[E] , 
                        [T1].[F] , 
                        [T1].[G] , 
                        [T1].[H] , 
                        [T1].[I] , 
                        [T1].[J] 
                    FROM [Item] AS [T1] where [J] > @LastUpdatedDateTime ORDER BY [T1].[LastUpdatedField] ASC
                </frame>
            </executionStack>
            <inputbuf>Proc [Database Id = 7 Object Id = 469576711]</inputbuf>
         </process>
         <process id="process5a514c8" taskpriority="0" logused="244" waitresource="KEY: 7:72057594152615936 (16f70bd264f5)" waittime="2535" ownerId="7732055725" transactionname="user_transaction" lasttranstarted="2014-03-17T17:48:31.437" XDES="0x6602dfa00" lockMode="X" schedulerid="13" kpid="21196" status="suspended" spid="267" sbid="0" ecid="0" priority="0" trancount="2" lastbatchstarted="2014-03-17T17:48:31.437" lastbatchcompleted="2014-03-17T17:48:31.437" clientapp=".Net SqlClient Data Provider" hostname="STO2AP07" hostpid="4908" loginname="(hidden)" isolationlevel="read committed (2)" xactid="7732055725" currentdb="7" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
            <executionStack>
               <frame procname="(hidden).dbo.AddToList" line="52" stmtstart="2484" stmtend="3294" sqlhandle="0x030007005cbf2019598be800cfa200000100000000000000">
                    UPDATE [Item] 
                    SET 
                        [A] = @A , 
                        [B] = @B , 
                        [C] = @C , 
                        [D] = @D , 
                        [E] = @E , 
                        [F] = @F , 
                        [G] = @G , 
                        [H] = @H , 
                        [I] = @I ,
                        [J] = @J 
                    WHERE [Id] = @Id
                </frame>
            </executionStack>
            <inputbuf>Proc [Database Id = 7 Object Id = 421576540]</inputbuf>
         </process>
      </process-list>
      <resource-list>
         <keylock hobtid="72057594152681472" dbid="7" objectname="(hidden).dbo.Item" indexname="PK_Item_1" id="lock47c381b80" mode="X" associatedObjectId="72057594152681472">
            <owner-list>
               <owner id="process5a514c8" mode="X" />
            </owner-list>
            <waiter-list>
               <waiter id="process3e37f62c8" mode="S" requestType="wait" />
            </waiter-list>
         </keylock>
         <keylock hobtid="72057594152615936" dbid="7" objectname="(hidden).dbo.Item" indexname="IX_LastUpdatedField" id="lock402a95800" mode="S" associatedObjectId="72057594152615936">
            <owner-list>
               <owner id="process3e37f62c8" mode="S" />
            </owner-list>
            <waiter-list>
               <waiter id="process5a514c8" mode="X" requestType="wait" />
            </waiter-list>
         </keylock>
      </resource-list>
   </deadlock>
</deadlock-list>

以下是名为GetList的存储过程：

ALTER PROCEDURE [dbo].[GetList]
    @LastUpdatedDateTime datetime,
    @NumRows int
WITH RECOMPILE
AS
BEGIN
    SET NOCOUNT ON;

    SELECT TOP (@NumRows)
           [T1].[Id]
         , [T1].[A]
         , [T1].[B]
         , [T1].[C]
         , [T1].[D]
         , [T1].[E]
         , [T1].[F]
         , [T1].[G]
         , [T1].[H]
         , [T1].[I]
         , [T1].[J]
      FROM [Item] AS [T1] where J >= @LastUpdatedDateTime
  ORDER BY [T1].[J] ASC
END

以下是名为 AddToList 的存储过程：

ALTER PROCEDURE [dbo].[AddToList]
    @Id int,
    @A varchar(30),
    @B decimal(18,2),
    @V varchar(30),
    @D varchar(512),
    @E datetime,
    @F datetime,
    @G bit,
    @H int,
    @I int
    @J datetime,
AS
IF NOT EXISTS(SELECT Id FROM Item WHERE [Id] = @Id)
    BEGIN
        SET NOCOUNT ON;
        INSERT INTO [Item] 
                  ( [Id] 
                  , [A]
                  , [B]
                  , [C]
                  , [D]
                  , [E]
                  , [F]
                  , [G]
                  , [H]
                  , [I]
                  , [J]
                  )
             VALUES
                  ( @Id
                  , @A
                  , @B
                  , @C
                  , @D
                  , @E
                  , @F
                  , @G
                  , @H
                  , @I
                  , @J
                  )
    END
ELSE
    BEGIN
        UPDATE [Item] SET
                   [A] = @A
                  , [B] = @B
                  , [C] = @C
                  , [D] = @D
                  , [E] = @E
                  , [F] = @F
                  , [G] = @G
                  , [H] = @H
                  , [I] = @I
                  , [J] = @J
        WHERE [Id] = @Id
    END

【参考方案1】：

选择这样做：

从 LastUpdatedDateTime 索引读取（S 锁） 查找对应的 CI 行（S 锁）

更新是这样的：

写入 CI（X 锁） 写入 LastUpdatedDateTime 索引（X 锁定）

他们以相反的顺序访问两个不兼容的资源。死锁。

阅读器是否在高于READ COMMITTED 的隔离级别下运行？ READ COMMITTED 应该在读取锁定的行后立即释放锁。

如果您可以使读取事务使用快照隔离模型，死锁将以简单、可靠和永久的方式消失。

如果不可能，请使用READ COMMITTED 隔离级别。

如果这不可行，您将不得不弄乱锁定提示（难以维护）或实现死锁重试逻辑。

【讨论】：

感谢您的快速回复！现在我想我明白他们是如何陷入僵局的。您不知道有一种方法可以跟踪获取锁的顺序吗？ READ COMMITTED 已经是当前的隔离级别了，还能死锁吗？

如果 iso 级别真的是 READ COMMITTED 他们不应该死锁。也许这里正在发生其他事情。 SQL Profiler 可以跟踪锁。

这肯定是 READ COMMITTED，我想我得进一步调查一下