.NET应用开发之SQLServer常见问题分析

日常我们开发.NET应用时会使用SQLServer数据库，对于SQLServer数据库的日常开发有一些技能和工具，准备给大家分享一下。

一、场景1：SQLServer死锁分析

 执行以下SQL，启用SQLServer死锁日志输出

EXEC sp_altermessage 1205, 'WITH_LOG', 'true'
DBCC TRACEON(1204,-1)
DBCC TRACEON(1222,-1)

运行一段时间后，系统出现死锁问题，可以从以下位置查看SQLServer异常日志的死锁信息

Program Files\Microsoft SQL Server\MSSQL. n \MSSQL\LOG\ERRORLOG

二、场景2：SQLServer索引锁片收集

SELECT S.name as 'Schema',
T.name as 'Table',
I.name as 'Index',
DDIPS.avg_fragmentation_in_percent,
DDIPS.page_count
FROM sys.dm_db_index_physical_stats (DB_ID(), NULL, NULL, NULL, NULL) AS DDIPS
INNER JOIN sys.tables T on T.object_id = DDIPS.object_id
INNER JOIN sys.schemas S on T.schema_id = S.schema_id
INNER JOIN sys.indexes I ON I.object_id = DDIPS.object_id
AND DDIPS.index_id = I.index_id
WHERE DDIPS.database_id = DB_ID()
and I.name is not null
AND DDIPS.avg_fragmentation_in_percent > 0
ORDER BY DDIPS.avg_fragmentation_in_percent desc

三、场景3：SQLServer重复索引分析

/* 执行这个脚本后，索引将会以三个报表的实行展现出来
1.  列出所有索引和约束的关键信息
2.  列出表潜在的冗余索引
3.  列出表潜在的反向索引
*/
-- 创建一个存放索引信息的表
DECLARE @AllIndexes TABLE (
 [Table ID] [int] NOT NULL,
 [Schema] [sysname] NOT NULL,
 [Table Name] [sysname] NOT NULL,
 [Index ID] [int] NULL,
 [Index Name] [nvarchar](128) NULL,
 [Index Type] [varchar](12) NOT NULL,
 [Constraint Type] [varchar](11) NOT NULL,
 [Object Type] [varchar](10) NOT NULL,
 [AllColName] [nvarchar](2078) NULL,
 [ColName1] [nvarchar](128) NULL,
 [ColName2] [nvarchar](128) NULL,
 [ColName3] [nvarchar](128) NULL,
 [ColName4] [nvarchar](128) NULL,
 [ColName5] [nvarchar](128) NULL,
 [ColName6] [nvarchar](128) NULL,
 [ColName7] [nvarchar](128) NULL,
 [ColName8] [nvarchar](128) NULL,
 [ColName9] [nvarchar](128) NULL,
 [ColName10] [nvarchar](128) NULL
)

--  加载索引信息到下面语句
INSERT INTO @AllIndexes
 ([Table ID],[Schema],[Table Name],[Index ID],[Index Name],[Index Type],[Constraint Type],[Object Type]
 ,[AllColName],[ColName1],[ColName2],[ColName3],[ColName4],[ColName5],[ColName6],[ColName7],[ColName8],
 [ColName9],[ColName10])
SELECT o.[object_id] AS [Table ID] ,u.[name] AS [Schema],o.[name] AS [Table Name],
 i.[index_id] AS [Index ID]
 , CASE i.[name]
 WHEN o.[name] THEN '** Same as Table Name **'
 ELSE i.[name] END AS [Index Name],
 CASE i.[type]
 WHEN 1 THEN 'CLUSTERED'
 WHEN 0 THEN 'HEAP'
 WHEN 2 THEN 'NONCLUSTERED'
 WHEN 3 THEN 'XML'
 ELSE 'UNKNOWN' END AS [Index Type],
 CASE
 WHEN (i.[is_primary_key]) = 1 THEN 'PRIMARY KEY'
 WHEN (i.[is_unique]) = 1 THEN 'UNIQUE'
 ELSE '' END AS [Constraint Type],
 CASE
 WHEN (i.[is_unique_constraint]) = 1
 OR (i.[is_primary_key]) = 1
 THEN 'CONSTRAINT'
 WHEN i.[type] = 0 THEN 'HEAP'
 WHEN i.[type] = 3 THEN 'XML INDEX'
 ELSE 'INDEX' END AS [Object Type],
 (SELECT COALESCE(c1.[name],'') FROM [sys].[columns] AS c1 INNER JOIN [sys].[index_columns] AS ic1
 ON c1.[object_id] = ic1.[object_id] AND c1.[column_id] = ic1.[column_id] AND ic1.[key_ordinal] = 1
 WHERE ic1.[object_id] = i.[object_id] AND ic1.[index_id] = i.[index_id]) +
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].['+ o.[name] + ']', i.[index_id], 2) IS NULL THEN ''
 ELSE ', '+INDEX_COL('[' + u.[name] + '].['+ o.[name] + ']', i.[index_id],2) END +
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id], 3) IS NULL THEN ''
 ELSE ', '+INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id],3) END +
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id], 4) IS NULL THEN ''
 ELSE ', '+INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id],4) END +
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].['+ o.[name] + ']', i.[index_id], 5) IS NULL THEN ''
 ELSE ', '+INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id],5) END  +
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id], 6) IS NULL THEN ''
 ELSE ', '+INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id],6) END +
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id], 7) IS NULL THEN ''
 ELSE ', '+INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id], 7) END +
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id],8) IS NULL THEN ''
 ELSE ', '+INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id],8) END +
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].['+ o.[name] + ']', i.[index_id], 9) IS NULL THEN ''
 ELSE ', '+INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id],9) END +
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].['+ o.[name] + ']', i.[index_id], 10) IS NULL THEN ''
 ELSE ', '+INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id],10) END  AS [AllColName],
 (SELECT COALESCE(c1.[name],'') FROM [sys].[columns] AS c1 INNER JOIN [sys].[index_columns] AS ic1
 ON c1.[object_id] = ic1.[object_id] AND c1.[column_id] = ic1.[column_id] AND ic1.[key_ordinal] = 1
 WHERE ic1.[object_id] = i.[object_id] AND ic1.[index_id] = i.[index_id])   AS [ColName1],
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].['+ o.[name] + ']', i.[index_id], 2) IS NULL THEN ''
 ELSE INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id],2) END AS [ColName2],
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id], 3) IS NULL THEN ''
 ELSE INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id],3) END AS [ColName3],
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].['+ o.[name] + ']', i.[index_id], 4) IS NULL THEN ''
 ELSE INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id],4) END AS [ColName4],
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].['+ o.[name] + ']', i.[index_id], 5) IS NULL THEN ''
 ELSE INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id],5) END AS [ColName5],
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].['+ o.[name] + ']', i.[index_id], 6) IS NULL THEN ''
 ELSE INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id],6) END AS [ColName6],
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id], 7) IS NULL THEN ''
 ELSE INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id],7) END AS [ColName7],
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].['+ o.[name] + ']', i.[index_id],8) IS NULL THEN ''
 ELSE INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id],8) END AS [ColName8],
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].['+ o.[name] + ']', i.[index_id], 9) IS NULL THEN ''
 ELSE INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id],9) END AS [ColName9],
 CASE
 WHEN INDEX_COL('[' + u.[name] + '].['+ o.[name] + ']', i.[index_id], 10) IS NULL THEN ''
 ELSE INDEX_COL('[' + u.[name] + '].[' + o.[name] + ']', i.[index_id],10) END AS [ColName10]
FROM [sys].[objects] AS o WITH (NOLOCK)
 LEFT OUTER JOIN [sys].[indexes] AS i WITH (NOLOCK)
 ON o.[object_id] = i.[object_id]
 JOIN [sys].[schemas] AS u WITH (NOLOCK)
 ON o.[schema_id] = u.[schema_id]
WHERE o.[type] = 'U' --AND i.[index_id] < 255
 AND o.[name] NOT IN ('dtproperties')
 AND i.[name] NOT LIKE '_WA_Sys_%'

-----------
SELECT 'Listing All Indexes' AS [Comments]

SELECT I.*
 FROM @AllIndexes AS I
 ORDER BY [Table Name]

-----------
SELECT 'Listing Possible Redundant Index keys' AS [Comments]

SELECT DISTINCT I.[Table Name], I.[Index Name] ,I.[Index Type],  I.[Constraint Type], I.[AllColName]
 FROM @AllIndexes AS I
 JOIN @AllIndexes AS I2
 ON I.[Table ID] = I2.[Table ID]
 AND I.[ColName1] = I2.[ColName1]
 AND I.[Index Name] <> I2.[Index Name]
 AND I.[Index Type] <> 'XML'
 ORDER BY I.[Table Name], I.[AllColName]

----------
SELECT 'Listing Possible Reverse Index keys' AS [Comments]

SELECT DISTINCT I.[Table Name], I.[Index Name], I.[Index Type],  I.[Constraint Type], I.[AllColName]
 FROM @AllIndexes AS I
 JOIN @AllIndexes AS I2
 ON I.[Table ID] = I2.[Table ID]
 AND I.[ColName1] = I2.[ColName2]
 AND I.[ColName2] = I2.[ColName1]
 AND I.[Index Name] <> I2.[Index Name]
 AND I.[Index Type] <> 'XML'

以上SQL语句，比较常用，分享给大家。

周国庆

2022/11/14