查詢oracle比較慢的session和sql

注：本文來源：sxhong   《查詢oracle比較慢的session和sql》

  1 ---查詢最慢的sql
  2 
  3 select * from (
  4 select parsing_user_id,executions,sorts
  5 command_type,disk_reads,sql_text from v$sqlarea order by disk_reads desc
  6 )where rownum<10
  7 
  8  ---查詢對應session
  9 
 10 select SE.SID,SE.SERIAL#,PR.SPID,
 11 SE.USERNAME,SE.STATUS,SE.TERMINAL,
 12 SE.PROGRAM,SE.MODULE,
 13 SE.SQL_ADDRESS,ST.EVENT,
 14 ST.P1TEXT,SI.PHYSICAL_READS,SI.BLOCK_CHANGES from v$session se,v$session_wait st,
 15 v$sess_io si,v$process pr
 16 where st.SID=se.SID and st.SID=si.SID
 17 AND SE.PADDR=PR.ADDR
 18 AND SE.SID>6
 19 AND ST.WAIT_TIME=0
 20 AND ST.EVENT NOT LIKE '%SQL%'
 21 ORDER BY PHYSICAL_READS DESC;
 22 SELECT sql_address FROM V$SESSION SS,V$SQLTEXT TT
 23 WHERE SS.SQL_HASH_VALUE=TT.HASH_VALUE AND SID=439;
 24 
 25 
 26 --v$sqltext：存儲的是完整的SQL,SQL被分割
 27 
 28 --v$sqlarea：存儲的SQL 和一些相關的信息，好比累計的執行次數，邏輯讀，物理讀等統計信息（統計）
 29 
 30 --v$sql：內存共享SQL區域中已經解析的SQL語句。（即時）
 31 
 32 
 33 
 34 --根據sid查找完整sql語句：
 35 
 36 select sql_text from v$sqltext a where a.hash_value = (select sql_hash_value from v$session b where b.sid = '&sid'    )
 37 order by piece asc
 38 
 39 
 40 
 41 select a.CPU_TIME,--CPU時間 百萬分之一（微秒）
 42        a.OPTIMIZER_MODE,--優化方式
 43        a.EXECUTIONS,--執行次數
 44        a.DISK_READS,--讀盤次數
 45        a.SHARABLE_MEM,--佔用shared pool的內存多少
 46        a.BUFFER_GETS,--讀取緩衝區的次數
 47        a.COMMAND_TYPE,--命令類型(3:select,2:insert;6:update;7delete;47:pl/sql程序單元)
 48        a.SQL_TEXT,--Sql語句
 49        a.SHARABLE_MEM,
 50        a.PERSISTENT_MEM,
 51        a.RUNTIME_MEM,
 52        a.PARSE_CALLS,
 53        a.DISK_READS,
 54        a.DIRECT_WRITES,
 55        a.CONCURRENCY_WAIT_TIME,
 56        a.USER_IO_WAIT_TIME
 57   from SYS.V_$SQLAREA a
 58  WHERE PARSING_SCHEMA_NAME = 'CHEA_FILL'--表空間
 59  order by a.CPU_TIME desc
 60 
 61 
 62 
 63 
 64 
 65 ---從V$SQLAREA中查詢最佔用資源的查詢
 66 select b.username username,a.disk_reads reads,
 67     a.executions exec,a.disk_reads/decode(a.executions,0,1,a.executions) rds_exec_ratio,
 68     a.sql_text Statement
 69 from  v$sqlarea a,dba_users b
 70 where a.parsing_user_id=b.user_id
 71  and a.disk_reads > 100000
 72 order by a.disk_reads desc;
 73 --用buffer_gets列來替換disk_reads列能夠獲得佔用最多內存的sql語句的相關信息。
 74 
 75 --v$sql：內存共享SQL區域中已經解析的SQL語句。（即時）
 76 
 77 --列出使用頻率最高的5個查詢：
 78 select sql_text,executions
 79 from (select sql_text,executions,
 80    rank() over
 81     (order by executions desc) exec_rank
 82    from v$sql)
 83 where exec_rank <=5;
 84 --消耗磁盤讀取最多的sql top5：
 85 select disk_reads,sql_text
 86 from (select sql_text,disk_reads,
 87    dense_rank() over
 88      (order by disk_reads desc) disk_reads_rank
 89    from v$sql)
 90 where disk_reads_rank <=5;
 91 
 92 --找出須要大量緩衝讀取（邏輯讀）操做的查詢：
 93 select buffer_gets,sql_text
 94 from (select sql_text,buffer_gets,
 95    dense_rank() over
 96      (order by buffer_gets desc) buffer_gets_rank
 97    from v$sql)
 98 where buffer_gets_rank<=5;
 99 
100 v$sqlarea字段定義：http://happyhou.blog.sohu.com/60494432.html

SQL_TEXT	VARCHAR2(1000)	First thousand characters of the SQL text for the current cursor
SQL_ID	VARCHAR2(13)	SQL identifier of the parent cursor in the library cache
SHARABLE_MEM	NUMBER	Amount of shared memory used by a cursor. If multiple child cursors exist, then the sum of all shared memory used by all child cursors.
PERSISTENT_MEM	NUMBER	Fixed amount of memory used for the lifetime of an open cursor. If multiple child cursors exist, the fixed sum of memory used for the lifetime of all the child cursors.
RUNTIME_MEM	NUMBER	Fixed amount of memory required during execution of a cursor. If multiple child cursors exist, the fixed sum of all memory required during execution of all the child cursors.
SORTS	NUMBER	Sum of the number of sorts that were done for all the child cursors
VERSION_COUNT	NUMBER	Number of child cursors that are present in the cache under this parent
LOADED_VERSIONS	NUMBER	Number of child cursors that are present in the cache and have their context heap (KGL heap 6) loaded
OPEN_VERSIONS	NUMBER	The number of child cursors that are currently open under this current parent
USERS_OPENING	NUMBER	Number of users that have any of the child cursors open
FETCHES	NUMBER	Number of fetches associated with the SQL statement
EXECUTIONS	NUMBER	Total number of executions, totalled over all the child cursors
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	Total number of users executing the statement over all child cursors
LOADS	NUMBER	Number of times the object was loaded or reloaded
FIRST_LOAD_TIME	VARCHAR2(19)	Timestamp of the parent creation time
INVALIDATIONS	NUMBER	Total number of invalidations over all the child cursors
PARSE_CALLS	NUMBER	Sum of all parse calls to all the child cursors under this parent
DISK_READS	NUMBER	Sum of the number of disk reads over all child cursors
DIRECT_WRITES	NUMBER	Sum of the number of direct writes over all child cursors
BUFFER_GETS	NUMBER	Sum of buffer gets over all child cursors
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	Total number of rows processed on behalf of this SQL statement
COMMAND_TYPE	NUMBER	Oracle command type definition
OPTIMIZER_MODE	VARCHAR2(25)	Mode under which the SQL statement was executed
PARSING_USER_ID	NUMBER	User ID of the user that has parsed the very first cursor under this parent