Performance 在Ms Sql 2008上，每三次插入速度都很慢

我有一个函数，可以将3行内容写入空表，如下所示：

INSERT [dbo].[yaf_ForumAccess] ([GroupID], [ForumID], [AccessMaskID]) VALUES (1, 8, 1) 
INSERT [dbo].[yaf_ForumAccess] ([GroupID], [ForumID], [AccessMaskID]) VALUES (2, 8, 4)
INSERT [dbo].[yaf_ForumAccess] ([GroupID], [ForumID], [AccessMaskID]) VALUES (3, 8, 3)

出于某种原因，只有第三个查询需要很长时间才能执行，而且每次插入都会延长执行时间

我尝试禁用表上的所有约束-结果相同。我就是不明白为什么前两个跑得这么快，而最后一个却要花这么长时间

任何帮助都将不胜感激

以下是MSMS运行的查询的统计信息：

查询：

ALTER TABLE [dbo].[yaf_ForumAccess] NOCHECK CONSTRAINT ALL
INSERT [dbo].[yaf_ForumAccess] ([GroupID], [ForumID], [AccessMaskID]) VALUES (1, 9, 1) 
INSERT [dbo].[yaf_ForumAccess] ([GroupID], [ForumID], [AccessMaskID]) VALUES (2, 9, 4)
INSERT [dbo].[yaf_ForumAccess] ([GroupID], [ForumID], [AccessMaskID]) VALUES (3, 9, 3)
ALTER TABLE [dbo].[yaf_ForumAccess] CHECK CONSTRAINT ALL

统计数据：

统计IO打开：

Table 'yaf_vaccess_group'. Scan count 0, logical reads 3, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_UserGroup'. Scan count 1, logical reads 709, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_AccessMask'. Scan count 0, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_Group'. Scan count 0, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Worktable'. Scan count 2, logical reads 7, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_ForumAccess'. Scan count 0, logical reads 4, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

(1 row(s) affected)

(1 row(s) affected)
Table 'yaf_vaccess_group'. Scan count 0, logical reads 8, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_UserGroup'. Scan count 1, logical reads 709, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_AccessMask'. Scan count 0, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_Group'. Scan count 0, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Worktable'. Scan count 2, logical reads 7, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_ForumAccess'. Scan count 0, logical reads 4, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

(1 row(s) affected)

(1 row(s) affected)
Table 'yaf_vaccess_group'. Scan count 0, logical reads 1340999, physical reads 0, read-ahead reads 3326, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_UserGroup'. Scan count 1, logical reads 709, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_Group'. Scan count 0, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_AccessMask'. Scan count 0, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Worktable'. Scan count 2, logical reads 7, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_ForumAccess'. Scan count 0, logical reads 4, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

(1 row(s) affected)

(1 row(s) affected)

yaf_vaccess_组视图：

CREATE VIEW [dbo].[yaf_vaccess_group]
WITH SCHEMABINDING
AS
        select
            b.UserID,
            c.ForumID,
            d.AccessMaskID,
            b.GroupID,
            ReadAccess      = convert(int,d.Flags & 1),
            PostAccess      = convert(int,d.Flags & 2),
            ReplyAccess     = convert(int,d.Flags & 4),
            PriorityAccess  = convert(int,d.Flags & 8),
            PollAccess      = convert(int,d.Flags & 16),
            VoteAccess      = convert(int,d.Flags & 32),
            ModeratorAccess = convert(int,d.Flags & 64),
            EditAccess      = convert(int,d.Flags & 128),
            DeleteAccess    = convert(int,d.Flags & 256),
            UploadAccess    = convert(int,d.Flags & 512),
            DownloadAccess  = convert(int,d.Flags & 1024),
            AdminGroup      = convert(int,e.Flags & 1)
        from
            [dbo].[yaf_UserGroup] b
            INNER JOIN [dbo].[yaf_ForumAccess] c on c.GroupID=b.GroupID
            INNER JOIN [dbo].[yaf_AccessMask] d on d.AccessMaskID=c.AccessMaskID
            INNER JOIN [dbo].[yaf_Group] e on e.GroupID=b.GroupID

CREATE UNIQUE CLUSTERED INDEX [yaf_vaccess_group_UserForum_PK] ON [dbo].[yaf_vaccess_group] 
(
    [UserID] ASC,
    [ForumID] ASC,
    [AccessMaskID] ASC,
    [GroupID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
GO

带4个插件的统计IO:

Table 'yaf_vaccess_group'. Scan count 0, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_UserGroup'. Scan count 1, logical reads 709, physical reads 0, read-ahead reads 7, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_AccessMask'. Scan count 0, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_Group'. Scan count 0, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Worktable'. Scan count 2, logical reads 7, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_ForumAccess'. Scan count 0, logical reads 6, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

(1 row(s) affected)

(1 row(s) affected)
Table 'yaf_vaccess_group'. Scan count 0, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_UserGroup'. Scan count 1, logical reads 709, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_AccessMask'. Scan count 0, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_Group'. Scan count 0, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Worktable'. Scan count 2, logical reads 7, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_ForumAccess'. Scan count 0, logical reads 4, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

(1 row(s) affected)

(1 row(s) affected)
Table 'yaf_vaccess_group'. Scan count 0, logical reads 1220894, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_UserGroup'. Scan count 1, logical reads 709, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_Group'. Scan count 0, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_AccessMask'. Scan count 0, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Worktable'. Scan count 2, logical reads 7, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_ForumAccess'. Scan count 0, logical reads 4, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

(1 row(s) affected)

(1 row(s) affected)
Table 'yaf_vaccess_group'. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Worktable'. Scan count 0, logical reads 0, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_UserGroup'. Scan count 1, logical reads 709, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_AccessMask'. Scan count 0, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'Worktable'. Scan count 2, logical reads 7, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.
Table 'yaf_ForumAccess'. Scan count 0, logical reads 4, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0.

(1 row(s) affected)

(1 row(s) affected)

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从您所展示的内容来看，并不是第三个查询占用了时间，而是实际打开检查约束的部分

当约束重新打开时，它必须验证所有记录是否良好。这意味着扫描整个表。根据大小的不同，它可能是IO绑定的，并且会把硬盘上的垃圾打出来

---

所以，我认为你需要做出决定。要么完全删除约束，要么停止打开和关闭约束。

该问题可能是由view vaccess_组上的索引引起的。由于视图没有填充，添加记录将需要SQL Server频繁拆分索引，并且在每三个索引之后，重新生成索引可能是维护索引结构/性能的最佳方法

尝试在索引中添加一些填充。有关信息，请参阅

CREATE UNIQUE CLUSTERED INDEX [yaf_vaccess_group_UserForum_PK] ON [dbo].[yaf_vaccess_group]
( 
    [UserID] ASC, 
    [ForumID] ASC, 
    [AccessMaskID] ASC, 
    [GroupID] ASC
)
WITH
(
    PAD_INDEX = ON,  -- CHANGE HERE
    FILLFACTOR = 50, -- AND HERE
    STATISTICS_NORECOMPUTE = OFF,
    SORT_IN_TEMPDB = OFF,
    IGNORE_DUP_KEY = OFF,
    DROP_EXISTING = OFF,
    ONLINE = OFF,
    ALLOW_ROW_LOCKS = ON,
    ALLOW_PAGE_LOCKS = ON
)
ON [PRIMARY]

---

顺便说一句，我未能在YAF数据库构建脚本中发现此索引的原因是，令人烦恼的是，它不在index.sql中。出于某种原因，他们将所有视图索引放在constraints.sql中

很好地尝试了屏幕截图-至少我根本无法放大它，所以它毫无用处，很遗憾。右键单击-查看图像或等效内容。[我添加了图像的直接链接]在SSMS中使用T-SQL插入记录时，您是否看到相同的行为？如果是，那么“慢”和“快”版本的查询计划之间有什么区别吗？所有批次都插入相同数量的记录吗？好的，统计IO输出让我信服了！yaf_vaccess_group上有什么触发因素吗？是的，我很确定是索引导致了这一点。看我的答案。现在你指出，这是显而易见的！当Chris写道“我尝试禁用表上的所有约束-结果相同”。一、 假设即使没有ALTERTABLE语句也会发生这种情况，这可能是不恰当的。但我认为你是对的。不，它发生在检查约束被移除的情况下。我只是把它们放进去让它更容易测试。而且，当我一步一步地完成代码时，第三次插入总是会暂停一段时间。好吧，让我把它关掉，然后再测试一次——是的，结果是一样的~第三次插入30秒。你能在这堆数据中添加第四个查询并测试它吗？哇，真不敢相信你竟然这么长时间来帮我。我稍后会把结果发回来。非常感谢你！