SQLServer性能优化分析--执行计划、耗时SQL排查和死锁处理_MsSqlserver

1 常用系统存储过程

1.1 查询表结构

exec sp_columns 'your_table', @column_name = 'table_column'

1.2 查询表索引

exec sp_helpindex 'your_table';

1.3 查询存储过程定义

exec sp_helptext 'sp_columns'

1.4 显示表的磁盘空间使用情况

exec sp_spaceused 'your_table';

2 查看执行计划

2.1 执行计划查询启用和关闭语法

set showplan_all on | off

2.2 案例：在test_db数据库中的user表上查询“学号=123“的学生，并分析哪些索引被系统采用

use test_db

go
set showplan_all on
go

select * from user where id = '123'

go
set showplan_all off
go
```javascript
set showplan_all on | off

3 查看磁盘使用率（statistics io）

3.1 执行计划查询启用和关闭语法

set statistics io on | off

3.2 案例

use book_db

go
set statistics io on
go

select * from book where id = 'ybzt246'

go
set statistics io off
go

4 查询时间耗时较长的语句

select top 20
    total_worker_time/1000 as [总消耗cpu 时间(ms)],execution_count [运行次数],
    qs.total_worker_time/qs.execution_count/1000 as [平均消耗cpu 时间(ms)],
    last_execution_time as [最后一次执行时间],max_worker_time /1000 as [最大执行时间(ms)],
    substring(qt.text,qs.statement_start_offset/2+1, 
        (case when qs.statement_end_offset = -1 
        then datalength(qt.text) 
        else qs.statement_end_offset end -qs.statement_start_offset)/2 + 1) 
    as [使用cpu的语法], qt.text [完整语法],
    dbname=db_name(qt.dbid),
    object_name(qt.objectid,qt.dbid) objectname
from sys.dm_exec_query_stats qs with(nolock)
cross apply sys.dm_exec_sql_text(qs.sql_handle) as qt
where execution_count>1
order by  total_worker_time desc

5 死锁处理

5.1 查询死锁进程id

select
    request_session_id spid,   
    object_name(resource_associated_entity_id) tablename    
from sys.dm_tran_locks   
where resource_type='object'

5.2 查询死锁进程信息