查看Sqlserver索引使用情況(數據庫中索引,表中索引)

轉自:https://blog.csdn.net/weixin_46867655/article/details/106330669
索引能加快速度,一般人都知道這個。

但是索引也有另一面,就是索引是有開銷的,每次update、delete、insert表的時候,都會維護相應的索引,把值維護到索引中去。所以索引並不是越多越好,建好索引之後需要定期的查看索引的使用,比如一條索引一次沒被查過,但是被修改了幾十萬甚至上百萬次,那麼這些修改都是需要資源消耗的。同時也要佔用磁盤空間,對於這些刪掉。對於user_seeks次數很少,或者爲0的索引,可以刪除這些索引;那如何查詢索引的使用情況呢?如下:

--1.要查看的數據庫的索引
use vims_sc --要查看的數據庫
 
select db_name(database_id) as N'數據庫名稱',
       object_name(a.object_id) as tbname,
       b.name N'索引名稱',
       user_seeks N'用戶索引查找次數',
       user_scans N'用戶索引掃描次數',
       last_user_seek N'最後查找時間',
       last_user_scan N'最後掃描時間',
       rows as N'表中的行數'
	   into #tmp
from sys.dm_db_index_usage_stats a join 
     sys.indexes b
     on a.index_id = b.index_id
     and a.object_id = b.object_id
     join sysindexes c
     on c.id = b.object_id
where database_id=db_id('vims_sc')   ---改成要查看的數據庫
and object_name(a.object_id) not like 'sys%'
order by user_seeks,user_scans,object_name(a.object_id)
 
select *from #tmp where tbname='AP_VC_Vaccine'
--2.查看錶的索引使用情況====================================
SELECT TOP 1000
o.name AS 表名
, i.name AS 索引名
, i.index_id AS 索引id
, dm_ius.user_seeks AS 搜索次數
, dm_ius.user_scans AS 掃描次數
, dm_ius.user_lookups AS 查找次數
, dm_ius.user_updates AS 更新次數
, p.TableRows as 錶行數
, 'DROP INDEX ' + QUOTENAME(i.name)
+ ' ON ' + QUOTENAME(s.name) + '.' + QUOTENAME(OBJECT_NAME(dm_ius.OBJECT_ID)) AS '刪除語句'
FROM sys.dm_db_index_usage_stats dm_ius
INNER JOIN sys.indexes i ON i.index_id = dm_ius.index_id AND dm_ius.OBJECT_ID = i.OBJECT_ID
INNER JOIN sys.objects o ON dm_ius.OBJECT_ID = o.OBJECT_ID
INNER JOIN sys.schemas s ON o.schema_id = s.schema_id
INNER JOIN (SELECT SUM(p.rows) TableRows, p.index_id, p.OBJECT_ID
FROM sys.partitions p GROUP BY p.index_id, p.OBJECT_ID) p
ON p.index_id = dm_ius.index_id AND dm_ius.OBJECT_ID = p.OBJECT_ID
WHERE OBJECTPROPERTY(dm_ius.OBJECT_ID,'IsUserTable') = 1
AND dm_ius.database_id = DB_ID()
--AND i.type_desc = 'nonclustered'--這裏指定了索引的類型,聚集索引或者非聚集索引
AND i.is_primary_key = 0
AND i.is_unique_constraint = 0
and o.name='StockOut'   --需要查找的表名
ORDER BY (dm_ius.user_seeks + dm_ius.user_scans + dm_ius.user_lookups) ASC
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