sql server 性能優化方法
一、查看是否有死鎖
DECLARE @tab TABLE(NAME varchar(100),value varchar(200));
INSERT INTO @tab EXEC('DBCC OPENTRAN WITH TABLERESULTS');
SELECT name,CAST(value AS DATETIME) startDate,getdate() currentDate
,DATEDIFF(s,CAST(value AS DATETIME),getdate()) diffsecond FROM @tab WHERE name in
('OLDACT_STARTTIME')
SELECT spid,
blocked,
DB_NAME(sp.dbid) AS DBName,
program_name,
waitresource,
lastwaittype,
sp.loginame,
sp.hostname,
a.[Text] AS [TextData],
SUBSTRING(A.text, sp.stmt_start / 2,
(CASE WHEN sp.stmt_end = -1 THEN DATALENGTH(A.text) ELSE sp.stmt_end
END - sp.stmt_start) / 2) AS [current_cmd]
FROM sys.sysprocesses AS sp OUTER APPLY sys.dm_exec_sql_text (sp.sql_handle) AS A
WHERE spid =(SELECT CASE WHEN ISNUMERIC(value)=0 THEN -1 ELSE value end FROM @tab WHERE name in
('OLDACT_SPID') )
二、查看當前正在執行的sql語句
SELECT [Spid] = session_id , ecid ,
[Database] = DB_NAME(sp.dbid) ,[User] = nt_username ,
[Status] = er.status , [Wait] = wait_type ,
[Individual Query] = SUBSTRING(qt.text,
er.statement_start_offset / 2,
( CASE WHEN er.statement_end_offset = -1
THEN LEN(CONVERT(NVARCHAR(MAX), qt.text))
* 2
ELSE er.statement_end_offset
END - er.statement_start_offset )
/ 2) ,
[Parent Query] = qt.text , Program = program_name ,hostname , nt_domain , start_time
FROM sys.dm_exec_requests er
INNER JOIN sys.sysprocesses sp ON er.session_id = sp.spid
CROSS APPLY sys.dm_exec_sql_text(er.sql_handle) AS qt
WHERE session_id > 50 -- Ignore system spids.
AND session_id NOT IN ( @@SPID ) -- Ignore this current statement.
ORDER BY 1 ,
2
--刪除解鎖
KILL 1000 --spid
三、查詢前 10 個可能是性能最差的 SQL 語句
SELECT TOP 10 TEXT AS 'SQL Statement'
,last_execution_time AS 'Last Execution Time'
,(total_logical_reads + total_physical_reads + total_logical_writes) / execution_count AS [Average IO]
,(total_worker_time / execution_count) / 1000000.0 AS [Average CPU Time (sec)]
,(total_elapsed_time / execution_count) / 1000000.0 AS [Average Elapsed Time (sec)]
,execution_count AS "Execution Count"
,qp.query_plan AS "Query Plan"
FROM sys.dm_exec_query_stats qs
CROSS APPLY sys.dm_exec_sql_text(qs.plan_handle) st
CROSS APPLY sys.dm_exec_query_plan(qs.plan_handle) qp
ORDER BY total_elapsed_time / execution_count DESC
where database_id=db_id('數據庫名稱') --指定數據庫
and object_name(a.object_id) not like 'sys%'
and object_name(a.object_id) like '表名' --指定索引表
and b.name is not null
--and b.name like '索引名' --指定索引名稱 可以先使用 sp_help '你的表名' 查看錶的結構和所有的索引信息
group by db_name(database_id) ,
object_name(a.object_id),
b.name,
user_seeks ,
user_scans
order by user_seeks,user_scans,object_name(a.object_id)
四、查詢邏輯讀取最高的sql
SELECT TOP ( 25 )
P.name AS [SP Name] ,
Deps.total_logical_reads AS [TotalLogicalReads] ,
deps.total_logical_reads / deps.execution_count AS [AvgLogicalReads] ,
deps.execution_count ,
ISNULL(deps.execution_count / DATEDIFF(SECOND, deps.cached_time,
GETDATE()), 0) AS [Calls/Second] ,
deps.total_elapsed_time ,
deps.total_elapsed_time / deps.execution_count AS [avg_elapsed_time] ,
deps.cached_time
FROM sys.procedures AS p
INNER JOIN sys.dm_exec_procedure_stats AS deps ON p.[Object_id] = deps.[Object_id]
WHERE deps.Database_id = DB_ID()
ORDER BY deps.total_logical_reads DESC
五、 查詢索引碎片
--創建變量 指定要查看的表
declare @table_id int
set @table_id=object_id('TableName')
--執行
dbcc showcontig(@table_id)
Logical Scan Fragmentation-邏輯掃描碎片:該百分比應該在0%到10%之間,高了則說明有外部碎片。
Extent Scan Fragmentation-擴展盤區掃描碎片:該百分比應該是0%,高了則說明有外部碎片。
掃描密度[最佳值:實際值]:該百分比應該儘可能靠近100%。低了則說明有外部碎片。
六、修改索引填充因子(FILLFACTOR:填充因子,ONLINE:ON 重建索引時表仍然可以正常使用)
--修改表下所有索引填充因子
ALTER INDEX ALL ON TableName REBUILD WITH (FILLFACTOR=90,ONLINE=ON)
--修改表下指定索引填充因子
ALTER INDEX indexName ON TableName REBUILD WITH (FILLFACTOR = 80);
七、查詢未使用過的索引
SELECT DB_NAME(diu.database_id) AS DatabaseName ,
s.name +'.' +QUOTENAME(o.name) AS TableName ,
i.index_id AS IndexID ,
i.name AS IndexName ,
CASE WHEN i.is_unique =1 THEN 'UNIQUE INDEX'
ELSE 'NOT UNIQUE INDEX' END AS IS_UNIQUE,
CASE WHEN i.is_disabled=1 THEN 'DISABLE'
ELSE 'ENABLE' END AS IndexStatus,
o.create_date AS IndexCreated,
STATS_DATE(o.object_id,i.index_id) AS StatisticsUpdateDate,
diu.user_seeks AS UserSeek ,
diu.user_scans AS UserScans ,
diu.user_lookups AS UserLookups ,
diu.user_updates AS UserUpdates ,
p.TableRows ,
'DROP INDEX ' + QUOTENAME(i.name)
+ ' ON ' + QUOTENAME(s.name) + '.'
+ QUOTENAME(OBJECT_NAME(diu.object_id)) +';' AS 'Drop Index Statement'
FROM sys.dm_db_index_usage_stats diu
INNER JOIN sys.indexes i ON i.index_id = diu.index_id
AND diu.object_id = i.object_id
INNER JOIN sys.objects o ON diu.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 = diu.index_id
AND diu.object_id = p.object_id
WHERE OBJECTPROPERTY(diu.object_id, 'IsUserTable') = 1
AND diu.database_id = DB_ID()
AND i.is_primary_key = 0 --排除主鍵索引
AND i.is_unique_constraint = 0 --排除唯一索引
AND diu.user_updates <> 0 --排除沒有數據變化的索引
AND diu.user_lookups = 0
AND diu.user_seeks = 0
AND diu.user_scans = 0
AND i.name IS NOT NULL --排除那些沒有任何索引的堆表
ORDER BY ( diu.user_seeks + diu.user_scans + diu.user_lookups ) ASC,diu.user_updates DESC;
GO
八、查詢表下索引使用情況
select db_name(database_id) as N'數據庫名稱',
object_name(a.object_id) as N'表名',
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',
max(last_user_seek) N'最後查找時間',
max(last_user_scan) N'最後掃描時間',
max(rows) as N'表中的行數'
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('數據庫名稱') --指定數據庫
and object_name(a.object_id) not like 'sys%'
and object_name(a.object_id) like '表名' --指定索引表
and b.name is not null
--and b.name like '索引名' --指定索引名稱 可以先使用 sp_help '你的表名' 查看錶的結構和所有的索引信息
group by db_name(database_id) ,
object_name(a.object_id),
b.name,
user_seeks ,
user_scans
order by user_seeks,user_scans,object_name(a.object_id)
九、查詢表結構信息
SELECT 表名 = CASE WHEN a.colorder = 1 THEN d.name
ELSE ''
END ,
表說明 = CASE WHEN a.colorder = 1 THEN ISNULL(f.value, '')
ELSE ''
END ,
字段序號 = a.colorder ,
字段名 = a.name ,
標識 = CASE WHEN COLUMNPROPERTY(a.id, a.name, 'IsIdentity') = 1
THEN '√'
ELSE ''
END ,
主鍵 = CASE WHEN EXISTS ( SELECT 1
FROM sysobjects
WHERE xtype = 'PK'
AND parent_obj = a.id
AND name IN (
SELECT name
FROM sysindexes
WHERE indid IN (
SELECT
indid
FROM sysindexkeys
WHERE id = a.id
AND colid = a.colid ) ) )
THEN '√'
ELSE ''
END ,
類型 = b.name ,
佔用字節數 = a.length ,
長度 = COLUMNPROPERTY(a.id, a.name, 'PRECISION') ,
小數位數 = ISNULL(COLUMNPROPERTY(a.id, a.name, 'Scale'), 0) ,
允許空 = CASE WHEN a.isnullable = 1 THEN '√'
ELSE ''
END ,
默認值 = ISNULL(e.text, '') ,
字段說明 = ISNULL(g.[value], '')
FROM syscolumns a
LEFT JOIN systypes b ON a.xusertype = b.xusertype
INNER JOIN sysobjects d ON a.id = d.id
AND d.xtype = 'U'
AND d.name <> 'dtproperties'
LEFT JOIN syscomments e ON a.cdefault = e.id
LEFT JOIN sys.extended_properties g ON a.id = G.major_id
AND a.colid = g.minor_id
LEFT JOIN sys.extended_properties f ON d.id = f.major_id
AND f.minor_id = 0
WHERE d.name = 'TableName' --如果只查詢指定表,加上此紅色where條件,tablename是要查詢的表名;去除紅色where條件查詢說有的表信息
ORDER BY a.id ,
a.colorder