Oracle性能檢測sql語句詳解
以下的文章主要是淺談Oracle性能檢測sql語句 ,我在一個(gè)信譽(yù)度很好的網(wǎng)站找到一個(gè)關(guān)于Oracle性能檢測sql語句的資料以及相關(guān)代碼的示例,拿出來供大家分享。以下就是文章的詳細(xì)內(nèi)容介紹。
Oracle性能檢測sql語句
1. 監(jiān)控事例的等待
- select event,sum(decode(wait_Time,0,0,1)) "Prev",
 - sum(decode(wait_Time,0,1,0)) "Curr",count(*) "Tot"
 - from v$session_Wait
 - group by event order by 4;
 
2. 回滾段的爭用情況
- select name, waits, gets, waits/gets "Ratio"
 - from v$rollstat a, v$rollname b
 - where a.usn = b.usn;
 
3. 監(jiān)控表空間的 I/O 比例
- select df.tablespace_name name,df.file_name "file",f.phyrds pyr,
 - f.phyblkrd pbr,f.phywrts pyw, f.phyblkwrt pbw
 - from v$filestat f, dba_data_files df
 - where f.file# = df.file_id
 - order by df.tablespace_name;
 
4. 監(jiān)控文件系統(tǒng)的 I/O 比例
- select substr(a.file#,1,2) "#", substr(a.name,1,30) "Name",
 - a.status, a.bytes, b.phyrds, b.phywrts
 - from v$datafile a, v$filestat b
 - where a.file# = b.file#;
 
5.在Oracle性能檢測中在某個(gè)用戶下找所有的索引
- select user_indexes.table_name, user_indexes.index_name,
 
uniqueness, column_name- from user_ind_columns, user_indexes
 - where user_ind_columns.index_name = user_indexes.index_name
 - and user_ind_columns.table_name = user_indexes.table_name
 - order by user_indexes.table_type, user_indexes.table_name,
 - user_indexes.index_name, column_position;
 
6. 監(jiān)控 SGA 的命中率
- select a.value + b.value "logical_reads", c.value "phys_reads",
 - round(100 * ((a.value+b.value)-c.value) / (a.value+b.value))
 
"BUFFER HIT RATIO"- from v$sysstat a, v$sysstat b, v$sysstat c
 - where a.statistic# = 38 and b.statistic# = 39
 - and c.statistic# = 40;
 
7. 監(jiān)控 SGA 中字典緩沖區(qū)的命中率
- select parameter, gets,Getmisses , getmisses/
 
(gets+getmisses)*100 "miss ratio",- (1-(sum(getmisses)/ (sum(gets)+sum(getmisses))))*100 "Hit ratio"
 - from v$rowcache
 - where gets+getmisses <>0
 - group by parameter, gets, getmisses;
 
以上的相關(guān)內(nèi)容就是對(duì)Oracle性能檢測sql語句的介紹,望你能有所收獲。
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