【1】查看堆表
--查看堆表且行大于等于10W的
select * from (
SELECT tables.NAME,
(SELECT rows
FROM sys.partitions
WHERE object_id = tables.object_id
AND index_id = 0 -- 0 is for heap
-- 1 is for clustered index
And rows >=100000
)AS numberofrows
FROM db_tank.sys.tables tables
WHERE Objectproperty(tables.object_id, N‘TableHasClustIndex‘) = 0
)t where numberofrows is not null
--另外一种办法select rows,object_name(id),indid from sysindexes where indid=0 and rows>=100000
【2】查看索引相关
-------------------查看缺失索引-----------------------------------------
SELECT
avg_total_user_cost * avg_user_impact * (user_seeks + user_scans)
AS PossibleImprovement
,last_user_seek
,last_user_scan
,statement AS Object
,‘CREATE INDEX [IDX_‘ + CONVERT(VARCHAR,GS.Group_Handle) + ‘_‘ +
CONVERT(VARCHAR,D.Index_Handle) + ‘_‘
+ REPLACE(REPLACE(REPLACE([statement],‘]‘,‘‘),‘[‘,‘‘),‘.‘,‘‘) +
‘]‘
+‘ ON ‘
+ [statement]
+ ‘ (‘ + ISNULL (equality_columns,‘‘)
+ CASE WHEN equality_columns IS NOT NULL AND inequality_columns IS
NOT NULL THEN ‘,‘ ELSE ‘‘ END
+ ISNULL (inequality_columns, ‘‘)
+ ‘)‘
+ ISNULL (‘ INCLUDE (‘ + included_columns + ‘)‘, ‘‘)
AS Create_Index_Syntax
FROM
sys.dm_db_missing_index_groups AS G
INNER JOIN
sys.dm_db_missing_index_group_stats AS GS
ON
GS.group_handle = G.index_group_handle
INNER JOIN
sys.dm_db_missing_index_details AS D
ON
G.index_handle = D.index_handle
Order By PossibleImprovement DESC
------------------缺失索引-----------------------
SELECT migs.group_handle, mid.*
FROM sys.dm_db_missing_index_group_stats AS migs
INNER JOIN sys.dm_db_missing_index_groups AS mig
ON (migs.group_handle = mig.index_group_handle)
INNER JOIN sys.dm_db_missing_index_details AS mid
ON (mig.index_handle = mid.index_handle)
WHERE migs.group_handle = 2
----------------------------------无用索引----------------------
SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED
SELECT
DB_NAME() AS DatbaseName
, SCHEMA_NAME(O.Schema_ID) AS SchemaName
, OBJECT_NAME(I.object_id) AS TableName
, I.name AS IndexName
INTO #TempNeverUsedIndexes
FROM sys.indexes I INNER JOIN sys.objects O ON I.object_id = O.object_id
WHERE 1=2
EXEC sp_MSForEachDB ‘USE [?]; INSERT INTO #TempNeverUsedIndexes
SELECT
DB_NAME() AS DatbaseName
, SCHEMA_NAME(O.Schema_ID) AS SchemaName
, OBJECT_NAME(I.object_id) AS TableName
, I.NAME AS IndexName
FROM sys.indexes I INNER JOIN sys.objects O ON I.object_id = O.object_id
LEFT OUTER JOIN sys.dm_db_index_usage_stats S ON S.object_id = I.object_id
AND I.index_id = S.index_id
AND DATABASE_ID = DB_ID()
WHERE OBJECTPROPERTY(O.object_id,‘‘IsMsShipped‘‘) = 0
AND I.name IS NOT NULL
AND S.object_id IS NULL‘
SELECT * FROM #TempNeverUsedIndexes
ORDER BY DatbaseName, SchemaName, TableName, IndexName
DROP TABLE #TempNeverUsedIndexes
--------------------------经常被大量更新，但是却基本不适用的索引项--------------------
SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED
SELECT
DB_NAME() AS DatabaseName
, SCHEMA_NAME(o.Schema_ID) AS SchemaName
, OBJECT_NAME(s.[object_id]) AS TableName
, i.name AS IndexName
, s.user_updates
, s.system_seeks + s.system_scans + s.system_lookups
AS [System usage]
INTO #TempUnusedIndexes
FROM sys.dm_db_index_usage_stats s
INNER JOIN sys.indexes i ON s.[object_id] = i.[object_id]
AND s.index_id = i.index_id
INNER JOIN sys.objects o ON i.object_id = O.object_id
WHERE 1=2
EXEC sp_MSForEachDB ‘USE [?]; INSERT INTO #TempUnusedIndexes
SELECT TOP 20
DB_NAME() AS DatabaseName
, SCHEMA_NAME(o.Schema_ID) AS SchemaName
, OBJECT_NAME(s.[object_id]) AS TableName
, i.name AS IndexName
, s.user_updates
, s.system_seeks + s.system_scans + s.system_lookups
AS [System usage]
FROM sys.dm_db_index_usage_stats s
INNER JOIN sys.indexes i ON s.[object_id] = i.[object_id]
AND s.index_id = i.index_id
INNER JOIN sys.objects o ON i.object_id = O.object_id
WHERE s.database_id = DB_ID()
AND OBJECTPROPERTY(s.[object_id], ‘‘IsMsShipped‘‘) = 0
AND s.user_seeks = 0
AND s.user_scans = 0
AND s.user_lookups = 0
AND i.name IS NOT NULL
ORDER BY s.user_updates DESC‘
SELECT TOP 20 * FROM #TempUnusedIndexes ORDER BY [user_updates] DESC
DROP TABLE #TempUnusedIndexes
----------------------查看未用索引----------------------------
SELECT
ind.Index_id,
obj.Name as TableName,
ind.Name as IndexName,
ind.Type_Desc,
indUsage.user_seeks,
indUsage.user_scans,
indUsage.user_lookups,
indUsage.user_updates,
indUsage.last_user_seek,
indUsage.last_user_scan,
‘drop index [‘ + ind.name + ‘] ON [‘ + obj.name + ‘]‘ as
DropIndexCommand
FROM
Sys.Indexes as ind
JOIN
Sys.Objects as obj
ON
ind.object_id=obj.Object_ID
LEFT JOIN
sys.dm_db_index_usage_stats indUsage
ON
ind.object_id = indUsage.object_id
AND
ind.Index_id=indUsage.Index_id
WHERE
ind.type_desc<>‘HEAP‘ and obj.type<>‘S‘
AND
objectproperty(obj.object_id,‘isusertable‘) = 1
AND
(isnull(indUsage.user_seeks,0) = 0
AND
isnull(indUsage.user_scans,0) = 0
AND
isnull(indUsage.user_lookups,0) = 0)
ORDER BY
obj.name,ind.Name
GO
【3】查看索引碎片
--查看索引碎片 select db_name(database_id) as ‘数据库名‘, object_name(t.object_id) as ‘表名‘, t.index_id as ‘索引id‘, t1.index_name as ‘索引名称‘, t1.type_desc as ‘索引类型‘, t1.column_name as ‘索引列名‘, t.partition_number as ‘当前索引所在分区‘, t.page_count as ‘页统计‘, t.avg_page_space_used_in_percent as ‘页使用率‘ , t.record_count as ‘页行记录数‘, t.avg_record_size_in_bytes as ‘平均每条记录大小(B)‘, t.avg_fragmentation_in_percent as ‘索引碎片比率‘, t.fragment_count as ‘索引中的碎片数量‘, t.avg_fragment_size_in_pages as ‘一个索引中碎片的平均页数‘ from sys.dm_db_index_physical_stats(db_id(‘db_tank‘),NULL,NULL,NULL,NULL) t join (select distinct t3.object_id,t3.index_id,object_name(t3.object_id) as ‘table_name‘,t3.name as ‘index_name‘,t3.type_desc, t1.name as ‘column_name‘ from sys.columns t1 join sys.index_columns t2 on t1.column_id = t2.column_id AND t1.object_id = t2.object_id join sys.indexes t3 on t2.index_id = t3.index_id AND t2.object_id = t3.object_id) t1 on t1.object_id = t.object_id AND t1.index_id = t.index_id where object_name(t.object_id) = ‘sys_users_goods‘ --查看所有表中对应的索引名与索引列 select t3.object_id,object_name(t3.object_id) as ‘table_name‘,t3.name as ‘index_name‘,t3.type_desc, t1.name as ‘column_name‘ from sys.columns t1 join sys.index_columns t2 on t1.column_id = t2.column_id AND t1.object_id = t2.object_id join sys.indexes t3 on t2.index_id = t3.index_id AND t2.object_id = t3.object_id where object_name(t3.object_id) = ‘sys_users_goods‘ --查看表中所有索引 SELECT name,type_desc FROM sys.indexes WHERE object_id=object_id(‘O_Orders‘) --根据索引名称查看对应的列 DBCC SHOW_STATISTICS(O_Orders,idx_order_status_2) DBCC SHOW_STATISTICS(O_Orders,IX_O_OrdersUID) --查找碎片率大于40%的 SELECT object_name(object_id) ,index_type_desc,alloc_unit_type_desc,avg_fragmentation_in_percent, fragment_count,avg_fragment_size_in_pages,page_count,record_count, avg_page_space_used_in_percent FROM sys.dm_db_index_physical_stats(DB_ID(‘DBNAME‘), OBJECT_ID(‘‘),NULL,NULL,‘Sampled‘) WHERE avg_fragmentation_in_percent>40
【3.1】在线重建DDL实践
use db_tank
go
--0、修改数据库为简单模式，以便加快效率，避免大量写日志造成频繁IO与文件过大
alter database db_tank set recovery simple
--1、declare variables
--select * from db_del..rebuild_db_tank20190513 where 索引名称=‘PK_GMActiveInfo‘
--alter index PK_GMActiveInfo on GMActiveInfo rebuild with(online=on)
--update db_del..rebuild_db_tank20190513 set flag=1 where 索引名称=‘PK_GMActiveInfo‘
--2、create table db_del..rebuild_db_tank20190513
select
db_name(t.database_id) as ‘数据库名‘,
object_name(t.object_id) as ‘表名‘,
t.index_id as ‘索引id‘,
t1.index_name as ‘索引名称‘,
t1.type_desc as ‘索引类型‘,
t1.column_name as ‘索引列名‘,
t.partition_number as ‘当前索引所在分区‘,
t.page_count as ‘页统计‘,
t.avg_fragmentation_in_percent as ‘索引碎片比率‘,
t.fragment_count as ‘索引中的碎片数量‘,
t.avg_fragment_size_in_pages as ‘一个索引中碎片的平均页数‘
,identity(int,1,1) rn
,0 as ‘flag‘
into db_del..rebuild_db_tank20190513
from sys.dm_db_index_physical_stats(db_id(‘db_tank‘),NULL,NULL,NULL,‘limited‘) t
join (select distinct t3.object_id,t3.index_id,object_name(t3.object_id) as ‘table_name‘,t3.name as ‘index_name‘,t3.type_desc, t1.name as ‘column_name‘
from sys.columns t1 join sys.index_columns t2 on t1.column_id = t2.column_id AND t1.object_id = t2.object_id
join sys.indexes t3 on t2.index_id = t3.index_id AND t2.object_id = t3.object_id) t1
on t1.object_id = t.object_id AND t1.index_id = t.index_id
where t.avg_fragmentation_in_percent > 5
--update ‘text‘,‘ntext‘,‘image‘,‘xml‘,‘varchar(max)‘,‘nvarchar(max)‘,‘varbinary(max)‘,‘nvarbinary(max)‘ not online mode,the flag=2
use db_tank
go
update t1
set flag=2
from db_del..rebuild_db_tank20190513 t1 join
(
select object_name(object_id) as table_name from sys.columns t1
where t1.max_length=-1
union
select object_name(object_id) from sys.columns t1 join
(select system_type_id from sys.types where name in (‘text‘,‘ntext‘,‘image‘,‘xml‘)) t2
on t1.system_type_id=t2.system_type_id
) t2 on t1.[表名]=t2.table_name
declare @index_name varchar(500),@table_name varchar(500),@avg_fragment int,@flag int,@temp_index_name varchar(500)
declare @rn int ,@rn_count int
declare @sql varchar(4000),@db_name varchar(100)
--3、init
select @rn=1,@rn_count=count(1) from db_del..rebuild_db_tank20190513
set @temp_index_name=‘‘
--4、do_mian
while @rn<=@rn_count
begin
select @index_name=[索引名称],@table_name=[表名],@avg_fragment=[索引碎片比率],@flag=flag from db_del..rebuild_db_tank20190513 where rn=@rn
IF @flag=0
begin --索引碎片率大于等于30%，则进行重建，否则进行重新整理
IF @avg_fragment>=30
BEGIN
SET @sql=‘alter index ‘+@index_name+‘ on ‘+@table_name+‘ rebuild with(online=on)‘
END
else
begin
SET @sql=‘alter index ‘+@index_name+‘ on ‘+@table_name+‘ reorganize‘
end
print @sql
exec(@sql)
update db_del..rebuild_db_tank20190513 set flag=1 where [索引名称]=@index_name and [表名]=@table_name
end
set @rn=@rn+1
end
--5
alter database db_tank set recovery bulk_logged
go
原文地址：https://www.cnblogs.com/gered/p/11044571.html
时间： 2024-08-02 20:00:42