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Accepted
Cade Roux
Asked: 2013-02-06 19:32:14 +0800 CST

由于索引锁定顺序，SQL Server 在两次更新上死锁

  • 772

我有两个更新 - 一个首先锁定 CI，然后锁定 NCI（状态），因为状态列也在更新。另一个已经在 NCI 上拥有 U 锁，因为它知道它正在更改，然后尝试在 CI 上获得 U 锁。

强制这些序列化的最简单方法是什么？使用表级提示似乎很奇怪，因为这是一个内部索引问题——只涉及一个表——UPDLOCK、HOLDLOCK 是否会自动应用于该表所需的所有索引，从而强制它被序列化？

以下是查询：

UPDATE htt_action_log
SET status = 'ABORTED', CLOSED = GETUTCDATE()
WHERE transition_uuid = '{F53ADDDA-E46B-4726-66D8-D7B640B66597}'
AND status = 'OPEN';

那个 X 锁定 CI 中的行（在 CREATED 列上），然后尝试 X 锁定包括状态列的 NCI。

UPDATE htt_action_log
SET status = 'RUNNING {36082BCD-EB52-4358-E3D3-4D96FD5B9F0F} 1360094342'
WHERE action_uuid = (SELECT TOP 1 action_uuid
                     FROM htt_action_log
                     WHERE transition_uuid = '{F53ADDDA-E46B-4726-66D8-D7B640B66597}'
                         AND status = 'OPEN'
                     ORDER BY action_seq)

这个 U 锁定了相同的 NCI - 我猜是嵌套查询，然后去锁定 CI 以进行更新。

因此，订单产生了死锁。

最简单的解决方案是强制两个查询完全阻塞 - 即序列化。强制执行此操作的最简单方法是什么，只需WITH (UPDLOCK, HOLDLOCK)添加对表格的引用（第一个中的一个，第二个中的两个）？

DDL：

请注意，客户端在此表上有更多索引，这些索引应该受此更新影响，但死锁图中未提及。

CREATE TABLE [dbo].[HTT_ACTION_LOG](
    [ACTION_UUID] [varchar](128) NOT NULL,
    [TRANSITION_UUID] [varchar](128) NOT NULL,
    [STATUS] [varchar](128) NOT NULL,
    [CREATED] [datetime] NOT NULL,
    [CLOSED] [datetime] NULL,
    [ACTION_SEQ] [int] NOT NULL,
    [ACTION_TYPE] [varchar](15) NOT NULL,
    [ACTION_NAME] [varchar](50) NOT NULL,
    [ACTION_RESULT] [varchar](8000) NULL,
    [PENDING_SINCE] [datetime] NULL,
    [ACTION_SQL] [varchar](8000) NULL,
    [ERROR_OK] [int] NULL,
    [ERROR_COND] [varchar](2048) NULL,
    [RETRY] [varchar](128) NULL,
 CONSTRAINT [PK_HTT_ACTION_LOG_1] UNIQUE NONCLUSTERED 
(
    [ACTION_UUID] ASC
)
)

CREATE CLUSTERED INDEX [IK_HTT_ACTION_LOG_2] ON [dbo].[HTT_ACTION_LOG] 
(
    [CREATED] ASC
)

CREATE NONCLUSTERED INDEX [IK_HTT_ACTION_LOG_1] ON [dbo].[HTT_ACTION_LOG] 
(
    [TRANSITION_UUID] ASC,
    [STATUS] ASC
)
INCLUDE ( [ACTION_UUID],
[ACTION_SEQ])

CREATE NONCLUSTERED INDEX [IK_HTT_ACTION_LOG_4] ON [dbo].[HTT_ACTION_LOG] 
(
    [ACTION_UUID] ASC,
    [STATUS] ASC
)

CREATE NONCLUSTERED INDEX [missing_index_11438530_11438529_HTT_ACTION_LOG] ON [dbo].[HTT_ACTION_LOG] 
(
    [TRANSITION_UUID] ASC,
    [ACTION_TYPE] ASC
)
INCLUDE ( [ACTION_NAME])

CREATE NONCLUSTERED INDEX [missing_index_7207590_7207589_HTT_ACTION_LOG] ON [dbo].[HTT_ACTION_LOG] 
(
    [STATUS] ASC
)
INCLUDE ( [CREATED],
[PENDING_SINCE],
[ACTION_NAME])

CREATE NONCLUSTERED INDEX [missing_index_8535421_8535420_HTT_ACTION_LOG] ON [dbo].[HTT_ACTION_LOG] 
(
    [TRANSITION_UUID] ASC
)
INCLUDE ( [ACTION_UUID],
[STATUS])

ALTER TABLE [dbo].[HTT_ACTION_LOG] SET (LOCK_ESCALATION = AUTO)

ALTER TABLE [dbo].[HTT_ACTION_LOG]  WITH CHECK ADD  CONSTRAINT [FK_HTT_ACTION_LOG_1] FOREIGN KEY([TRANSITION_UUID])
REFERENCES [dbo].[HTT_TRANSITION_LOG] ([TRANSITION_UUID])

ALTER TABLE [dbo].[HTT_ACTION_LOG] CHECK CONSTRAINT [FK_HTT_ACTION_LOG_1]

ALTER TABLE [dbo].[HTT_ACTION_LOG] ADD  DEFAULT ('OPEN') FOR [STATUS]

ALTER TABLE [dbo].[HTT_ACTION_LOG] ADD  DEFAULT (getutcdate()) FOR [CREATED]

ALTER TABLE [dbo].[HTT_ACTION_LOG] ADD  DEFAULT ((0)) FOR [ERROR_OK]
sql-server deadlock

1 个回答

  1. Best Answer

    这两个查询的最佳索引与索引的现有定义相距不远IK_HTT_ACTION_LOG_1（添加ACTION_UUID到INCLUDE下面的改进索引中）：

    CREATE INDEX nc1
ON dbo.HTT_ACTION_LOG
(
    TRANSITION_UUID,
    STATUS,
    ACTION_SEQ
);

    第一个查询是：

    UPDATE dbo.HTT_ACTION_LOG
SET [STATUS] = 'ABORTED', 
    CLOSED = GETUTCDATE()
WHERE
    TRANSITION_UUID = '{F53ADDDA-E46B-4726-66D8-D7B640B66597}'
    AND [STATUS] = 'OPEN';

    给出以下执行计划：

    更新 1

    第二个查询可以这样表示：

    UPDATE ToUpdate 
SET [STATUS] = 'RUNNING {36082BCD-EB52-4358-E3D3-4D96FD5B9F0F} 1360094342'
FROM
(
    SELECT TOP (1)
        hal.[STATUS]
    FROM dbo.HTT_ACTION_LOG AS hal
    WHERE
        hal.transition_uuid = '{F53ADDDA-E46B-4726-66D8-D7B640B66597}'
        AND hal.[STATUS] = 'OPEN'
    ORDER BY
        hal.ACTION_SEQ ASC
) AS ToUpdate;

    给出这个执行计划：

    更新 2

    这两个查询现在以相同的顺序访问相同的资源，同时在计划的读取端锁定更少的行。执行引擎在读取新索引时会自动取UPDLOCKs，提供您正在寻找的序列化。

    • 13

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