查詢oracle比較慢的session和sql

https://www.cnblogs.com/gaochsh/p/5442737.html

--查詢最慢的sql

select * from (
select parsing_user_id,executions,sorts
command_type,disk_reads,sql_text from v$sqlarea order by disk_reads desc
)where rownum<10

 --查詢對應session

select SE.SID,SE.SERIAL#,PR.SPID,
SE.USERNAME,SE.STATUS,SE.TERMINAL,
SE.PROGRAM,SE.MODULE,
SE.SQL_ADDRESS,ST.EVENT,
ST.P1TEXT,SI.PHYSICAL_READS,SI.BLOCK_CHANGES from v$session se,v$session_wait st,
v$sess_io si,v$process pr
where st.SID=se.SID and st.SID=si.SID
AND SE.PADDR=PR.ADDR
AND SE.SID>6
AND ST.WAIT_TIME=0
AND ST.EVENT NOT LIKE '%SQL%'
ORDER BY PHYSICAL_READS DESC;
SELECT sql_address FROM V$SESSION SS,V$SQLTEXT TT
WHERE SS.SQL_HASH_VALUE=TT.HASH_VALUE AND SID=439;
 

v$sqltext：存儲的是完整的SQL,SQL被分割

v$sqlarea：存儲的SQL 和一些相關的信息，好比累計的執行次數，邏輯讀，物理讀等統計信息（統計）

v$sql：內存共享SQL區域中已經解析的SQL語句。（即時）

 

根據sid查找完整sql語句：

select sql_text from v$sqltext a where a.hash_value = (select sql_hash_value from v$session b where b.sid = '&sid'    )
order by piece asc

 

select a.CPU_TIME,--CPU時間 百萬分之一（微秒）
       a.OPTIMIZER_MODE,--優化方式
       a.EXECUTIONS,--執行次數
       a.DISK_READS,--讀盤次數
       a.SHARABLE_MEM,--佔用shared pool的內存多少
       a.BUFFER_GETS,--讀取緩衝區的次數
       a.COMMAND_TYPE,--命令類型(3:select,2:insert;6:update;7delete;47:pl/sql程序單元)
       a.SQL_TEXT,--Sql語句
       a.SHARABLE_MEM,
       a.PERSISTENT_MEM,
       a.RUNTIME_MEM,
       a.PARSE_CALLS,
       a.DISK_READS,
       a.DIRECT_WRITES,
       a.CONCURRENCY_WAIT_TIME,
       a.USER_IO_WAIT_TIME
  from SYS.V_$SQLAREA a
 WHERE PARSING_SCHEMA_NAME = 'CHEA_FILL'--表空間
 order by a.CPU_TIME desc

 

引用：http://jenniferok.iteye.com/blog/700985

從V$SQLAREA中查詢最佔用資源的查詢

select b.username username,a.disk_reads reads,
    a.executions exec,a.disk_reads/decode(a.executions,0,1,a.executions) rds_exec_ratio,
    a.sql_text Statement
from  v$sqlarea a,dba_users b
where a.parsing_user_id=b.user_id
 and a.disk_reads > 100000
order by a.disk_reads desc;

用buffer_gets列來替換disk_reads列能夠獲得佔用最多內存的sql語句的相關信息。

 

v$sql：內存共享SQL區域中已經解析的SQL語句。（即時）

列出使用頻率最高的5個查詢：

select sql_text,executions
from (select sql_text,executions,
   rank() over
    (order by executions desc) exec_rank
   from v$sql)
where exec_rank <=5;

消耗磁盤讀取最多的sql top5：
select disk_reads,sql_text
from (select sql_text,disk_reads,
   dense_rank() over
     (order by disk_reads desc) disk_reads_rank
   from v$sql)
where disk_reads_rank <=5;

找出須要大量緩衝讀取（邏輯讀）操做的查詢：

select buffer_gets,sql_text
from (select sql_text,buffer_gets,
   dense_rank() over
     (order by buffer_gets desc) buffer_gets_rank
   from v$sql)
where buffer_gets_rank<=5;

 

v$sqlarea字段定義：http://happyhou.blog.sohu.com/60494432.html

 

 

SQL_TEXT	VARCHAR2(1000)	SQL文本的前 1000個字符
SQL_ID	VARCHAR2(13)	SQL identifier of the parent cursor in the library cache
SHARABLE_MEM	NUMBER	佔用的共享內存大小 (單位： byte)
PERSISTENT_MEM	NUMBER	生命期內的固定內存大小 (單位： byte)
RUNTIME_MEM	NUMBER	執行期內的固定內存大小
SORTS	NUMBER	完成的排序數
VERSION_COUNT	NUMBER	Number of child cursors that are present in the cache under this parent
LOADED_VERSIONS	NUMBER	顯示上下文堆是否載入， 1是 0否
OPEN_VERSIONS	NUMBER	顯示子游標是否被鎖， 1是 0否
USERS_OPENING	NUMBER	執行語句的用戶數
FETCHES	NUMBER	SQL語句的 fetch數。
EXECUTIONS	NUMBER	自它被載入緩存庫後的執行次數
END_OF_FETCH_COUNT	NUMBER	Number of times this cursor was fully executed since the cursor was brought into the library cache. The value of this statistic is not incremented when the cursor is partially executed, either because it failed during the execution or because only the first few rows produced by this cursor are fetched before the cursor is closed or re-executed. By definition, the value of theEND_OF_FETCH_COUNT column should be less or equal to the value of the EXECUTIONS column.
USERS_EXECUTING	NUMBER	執行語句的用戶數
LOADS	NUMBER	對象被載入過的次數
FIRST_LOAD_TIME	VARCHAR2(19)	初次載入時間
INVALIDATIONS	NUMBER	無效的次數
PARSE_CALLS	NUMBER	解析調用次數
DISK_READS	NUMBER	讀磁盤次數
DIRECT_WRITES	NUMBER	Sum of the number of direct writes over all child cursors
BUFFER_GETS	NUMBER	讀緩存區次數
APPLICATION_WAIT_TIME	NUMBER	Application wait time
CONCURRENCY_WAIT_TIME	NUMBER	Concurrency wait time
CLUSTER_WAIT_TIME	NUMBER	Cluster wait time
USER_IO_WAIT_TIME	NUMBER	User I/O Wait Time
PLSQL_EXEC_TIME	NUMBER	PL/SQL execution time
JAVA_EXEC_TIME	NUMBER	Java execution time
ROWS_PROCESSED	NUMBER	解析 SQL語句返回的總列數
COMMAND_TYPE	NUMBER	命令類型代號
OPTIMIZER_MODE	VARCHAR2(25)	QL語句的優化器模型
PARSING_USER_ID	NUMBER	第一個解析的用戶 ID
PARSING_SCHEMA_ID	NUMBER	第一個解析的計劃 ID