SQL服务器创建主键约束重复键错误

Question

我的一个 SQL 命令从我们的一个存储过程中获取时遇到了一些奇怪的行为。

此命令遵循以下执行顺序：

1) Drop table

2) Select * into table name from live server

3) Alter table to apply PK - this step fails once out of 4 daily executions

我的SQL声明：

 IF  EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N' 
 [inf].[tblBase_MyTable]') AND type in (N'U'))
 DROP TABLE [inf].[tblBase_MyTable]

 SELECT * INTO [inf].[tblBase_MyTable]
 FROM LiveServer.KMS_ALLOCATION WITH (NOLOCK)

 ALTER TABLE [inf].[tblBase_MyTable] ADD  
 CONSTRAINT [PK_KMS_ALLOCATION] PRIMARY KEY NONCLUSTERED 
 (
   [ID] ASC
  )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = 
 OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON)

 GRANT SELECT ON [inf].[tblBase_MyTable] TO ourGroup

考虑到 table 被删除，这很奇怪，我认为索引/键也会被删除。但是我每天都在同一时间收到此错误。任何建议将不胜感激。

错误：

The CREATE UNIQUE INDEX statement terminated because a duplicate key was found for the object name 'inf.tblBase_MyTable' and the index name 'PK_KMS_ALLOCATION'.

Answer 1

[inf].[tblBase_MyTable] table 中的重复键实际上是可能的，这要归功于 WITH (NOLOCK) 允许 "dirty reads" 的提示。查看详细描述此内容的博客：SQL Server NOLOCK Hint & other poor ideas:

What many people think NOLOCK is doing

Most people think the NOLOCK hint just reads rows & doesn’t have to wait till others have committed their updates or selects. If someone is updating, that is OK. If they’ve changed a value then 99.999% of the time they will commit, so it’s OK to read it before they commit. If they haven’t changed the record yet then it saves me waiting, its like my transaction happened before theirs did.

The Problem

The issue is that transactions do more than just update the row. Often they require an index to be updated OR they run out of space on the data page. This may require new pages to be allocated & existing rows on that page to be moved, called a PageSplit. It is possible for your select to completely miss a number of rows &/or count other rows twice.

Answer 2

好吧...您可能需要重复创建新的 table 并填充它，直到来自 @DarkoMartinovic 的 check-query 不 return 重复。只有这样你才能继续添加PK。但是这个解决方案可能会给您的实时系统带来沉重的负担。而且您无法保证您也拥有数据的 1:1 副本。

Answer 3

在查看了此处的各种有用评论后，我决定（暂时）不实施 SNAPSHOT 隔离，因为此接口未使用适当的暂存环境。

要转移到这意味着要么创建一个临时区域并将该数据库设置为 READ COMMITTED SNAPSHOT 隔离，然后重建整个界面。

为此，在节省开发时间的基础上，我们选择确保在应用 PK 之前处理任何可能从源代码中复制的 ghost 读取。

就目标服务器的性能而言，这绝不是理想的解决方案，但现在会提供一些空间，并且肯定会消除之前的错误。

SQL 方法如下：

DECLARE @ALLOCTABLE TABLE 
(SEQ INT, ID NVARCHAR(1000), CLASSID NVARCHAR(1000), [VERSION] NVARCHAR(25), [TYPE] 
NVARCHAR(100), VERSIONSEQUENCE NVARCHAR(100), VERSIONSEQUENCE_TO NVARCHAR(100), 
BRANCHID NVARCHAR(100), ISDELETED INT, RESOURCE_CLASS NVARCHAR(25), RESOURCE_ID 
NVARCHAR(100), WARD_ID NVARCHAR(100), ISCOMPLETE INT, TASK_ID NVARCHAR(100));

------- ALLOCATION
IF  EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[inf]. 
[tblBase_MyTable]') AND type in (N'U'))
DROP TABLE [inf].[tblBase_MyTable]

SELECT * INTO [inf].[tblBase_MyTable]
FROM LiveServer.KMS_ALLOCATION WITH (NOLOCK)

INSERT INTO @ALLOCTABLE
SELECT *
  FROM
   (SELECT 
   ROW_NUMBER() OVER (PARTITION BY ID ORDER BY ISCOMPLETE DESC) SEQ, AL.*
   FROM [inf].[tblBase_MyTable] AL
 )DUPS
 WHERE SEQ >1

 DELETE FROM [inf].[tblBase_MyTable]
 WHERE ID IN (SELECT ID FROM @ALLOCTABLE)
 AND ISCOMPLETE = 0

ALTER TABLE [inf].[tblBase_MyTable] ADD  CONSTRAINT 
[PK_KMS_ALLOCATION] PRIMARY KEY NONCLUSTERED 
  (
   [ID] ASC
  )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF,  ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON)

GRANT SELECT ON [inf].[tblBase_MyTable] TO OurGroup

SQL服务器创建主键约束重复键错误

SQL Server create primary key constraint duplicate key error

sql

tsql

sql-server

sql-server-2008