SQL_Server高级进阶之索引优化查询!valve_index_2.0?

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1.1、查找缺失索引SELECTA.USER_SEEKS查找次数,A.USER_SCANS扫描次数,ROUND(A.AVG_TOTAL_USER_COST,2)减少的用户查询的平均成本,A.AVG_USER_IMPACT可能获得的平均百分比收益,ROUND((

1.1、查找缺失索引

SQL_Server高级进阶之索引优化查询!valve_index_2.0?

SELECT A.USER_SEEKS 查找次数,A.USER_SCANS 扫描次数,    ROUND(A.AVG_TOTAL_USER_COST,2) 减少的用户查询的平均成本,A.AVG_USER_IMPACT 可能获得的平均百分比收益,    ROUND((A.USER_SEEKS+A.USER_SCANS)*A.AVG_TOTAL_USER_COST*A.AVG_USER_IMPACT/100,2) 可能的改进优势,    A.LAST_USER_SEEK 最近查找时间,A.LAST_USER_SCAN 最近扫描时间,C.[STATEMENT] 表名,    'CREATE INDEX [IDX_'        +CONVERT(VARCHAR,A.GROUP_HANDLE)+'_'+CONVERT(VARCHAR,C.INDEX_HANDLE)+'_'+REPLACE(REPLACE(REPLACE(C.[STATEMENT],']',''),'[',''),'.','')        +']'+' ON '+C.[STATEMENT]+ ' ('        +ISNULL(C.EQUALITY_COLUMNS,'')        +CASE WHEN NOT C.EQUALITY_COLUMNS IS NULL AND NOT C.INEQUALITY_COLUMNS IS NULL THEN ',' ELSE '' END        +ISNULL(C.INEQUALITY_COLUMNS,'')        +')'        +ISNULL(' INCLUDE ('+C.INCLUDED_COLUMNS+')','') '创建语句'FROM sys.dm_db_missing_index_group_stats A INNER JOIN sys.dm_db_missing_index_groups B ON A.GROUP_HANDLE=B.INDEX_GROUP_HANDLE    INNER JOIN sys.dm_db_missing_index_details C ON B.INDEX_HANDLE=C.INDEX_HANDLEWHERE C.DATABASE_ID=DB_ID()    --默认当前数据库,若指定数据库则使用DB_ID(['DB_NAME'])ORDER BY ROUND(A.USER_SEEKS*A.AVG_TOTAL_USER_COST*A.AVG_USER_IMPACT/100,2) DESC
SQL_Server高级进阶之索引优化查询!valve_index_2.0?

1.2、查找未使用索引

SQL_Server高级进阶之索引优化查询!valve_index_2.0?

SELECT C.NAME 表名,B.INDEX_ID 索引ID,B.NAME 索引名,    A.USER_SEEKS 搜索次数,A.USER_SCANS 扫描次数,A.USER_LOOKUPS 查找次数,    A.USER_UPDATES 更新次数,E.TABLEROWS 表行数,    'DROP INDEX '+QUOTENAME(B.NAME)+' ON '+QUOTENAME(D.NAME)+'.'+QUOTENAME(OBJECT_NAME(A.OBJECT_ID)) '删除语句'FROM sys.dm_db_index_usage_stats A INNER JOIN sys.indexes B ON A.INDEX_ID=B.INDEX_ID AND A.OBJECT_ID=B.OBJECT_ID    INNER JOIN sys.objects C ON A.OBJECT_ID=C.OBJECT_ID    INNER JOIN sys.schemas D ON C.schema_id=D.schema_id    INNER JOIN         (            SELECT INDEX_ID,OBJECT_ID,SUM(ROWS) TABLEROWS            FROM sys.partitions            GROUP BY INDEX_ID,OBJECT_ID        ) E ON A.INDEX_ID=E.INDEX_ID AND A.OBJECT_ID=E.OBJECT_IDWHERE OBJECTPROPERTY(A.OBJECT_ID,'IsUserTable')=1 AND A.DATABASE_ID=DB_ID()    AND B.TYPE_DESC='NONCLUSTERED' AND B.IS_PRIMARY_KEY=0 AND B.IS_UNIQUE_CONSTRAINT=0    --AND C.NAME='INVMB'    --根据实际修改表名ORDER BY (A.USER_SEEKS+A.USER_SCANS+A.USER_LOOKUPS) ASC
SQL_Server高级进阶之索引优化查询!valve_index_2.0?

当更新次数很大而搜索次数及扫描次数很小或为0时,说明该索引一直在更新但基本不被使用,因而也未对查询提供多少帮助,所以可以考虑删除。

1.3、查看索引使用情况

SELECT OBJECT_NAME(A.[OBJECT_ID]) 表名,B.INDEX_ID 索引ID,B.[NAME] 索引名称,B.[TYPE_DESC] 索引类型,
    A.USER_SEEKS+A.USER_SCANS+A.USER_LOOKUPS 读,A.USER_UPDATES 写,B.FILL_FACTOR 填充因子
FROM sys.dm_db_index_usage_stats A INNER JOIN sys.indexes B ON A.[OBJECT_ID]=B.[OBJECT_ID] AND A.INDEX_ID=B.INDEX_ID
WHERE OBJECTPROPERTY(A.[OBJECT_ID],'ISUSERTABLE')=1 
    AND A.DATABASE_ID=DB_ID()    --默认当前数据库,若指定数据库则使用DB_ID(['DB_NAME'])
ORDER BY OBJECT_NAME(A.[OBJECT_ID]),A.USER_UPDATES DESC,A.USER_SEEKS+A.USER_SCANS+A.USER_LOOKUPS DESC

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