oracle-查詢執行速度慢的sql

Oracle 查詢天天執行慢的SQL 2014-12-11 18:00:04

分類： Oracle

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連接： http://blog.itpub.net/28602568/viewspace-1364844/

標題： Oracle 查詢天天執行慢的SQL

做者： ｌōττéｒｙ©版權全部[文章容許轉載,但必須以連接方式註明源地址,不然追究法律責任.]

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前言：

 工做中的您是否有 想對天天慢的sql進行查詢、彙總或者行優化等狀況，以下SQL但願對您有幫助

 

 

 

--- 查詢天天執行慢的SQL：

SELECT S.SQL_TEXT,

       S.SQL_FULLTEXT,

       S.SQL_ID,

       ROUND(ELAPSED_TIME / 1000000 / (CASE

               WHEN (EXECUTIONS = 0 OR NVL(EXECUTIONS, 1 ) = 1) THEN

                1

               ELSE

                EXECUTIONS

             END),

             2) "執行時間'S'",

       S.EXECUTIONS "執行次數",

       S.OPTIMIZER_COST "COST",

       S.SORTS,

       S.MODULE, --鏈接模式（JDBC THIN CLIENT：程序）

       -- S.LOCKED_TOTAL,

       S.PHYSICAL_READ_BYTES "物理讀",

       -- S.PHYSICAL_READ_REQUESTS "物理讀請求",

       S.PHYSICAL_WRITE_REQUESTS "物理寫",

       -- S.PHYSICAL_WRITE_BYTES "物理寫請求",

       S.ROWS_PROCESSED      "返回行數",

       S.DISK_READS          "磁盤讀",

       S.DIRECT_WRITES       "直接路徑寫",

       S.PARSING_SCHEMA_NAME,

       S.LAST_ACTIVE_TIME

  FROM GV$SQLAREA S

 WHERE ROUND(ELAPSED_TIME / 1000000 / (CASE

               WHEN (EXECUTIONS = 0 OR NVL(EXECUTIONS, 1 ) = 1) THEN

                1

               ELSE

                EXECUTIONS

             END),

             2) > 5 --100 0000微秒=1S

   AND S.PARSING_SCHEMA_NAME = USER

   AND TO_CHAR(S.LAST_LOAD_TIME, 'YYYY-MM-DD') =

       TO_CHAR( SYSDATE, 'YYYY-MM-DD' )

   AND S.COMMAND_TYPE IN (2 , 3, 5, 6 , 189)

 ORDER BY "執行時間'S'" DESC;

 

/*  SQL中 COMMAND_TYPE意義: 

2：INSERT

3：SELECT

6：UPDATE

7：DELETE

189：MERGE

詳情可經過查找V$SQLCOMMAND視圖  */

 

V$SQLAREA    官網解釋： http://docs.oracle.com/cd/E11882_01/server.112/e40402/dynviews_3064.htm#REFRN30259 

V$SQLCOMMAND 官網解釋： http://docs.oracle.com/cd/E11882_01/server.112/e40402/dynviews_3066.htm#REFRN30632 

 

 

 

part2: 

性能查詢的經常使用幾個sql

--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)	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
PARSING_SCHEMA_ID	NUMBER	Schema ID that was used to parse this child cursor
KEPT_VERSIONS	NUMBER	Number of child cursors that have been marked to be kept using the DBMS_SHARED_POOL package
ADDRESS	RAW(4 | 8)	Address of the handle to the parent for this cursor
HASH_VALUE	NUMBER	Hash value of the parent statement in the library cache
OLD_HASH_VALUE	NUMBER	Old SQL hash value
MODULE	VARCHAR2(64)	Contains the name of the module that was executing at the time that the SQL statement was first parsed as set by calling DBMS_APPLICATION_INFO .SET_MODULE
MODULE_HASH	NUMBER	Hash value of the module that is named in the MODULEcolumn
ACTION	VARCHAR2(64)	Contains the name of the action that was executing at the time that the SQL statement was first parsed as set by calling DBMS_APPLICATION_INFO .SET_ACTION
ACTION_HASH	NUMBER	Hash value of the action that is named in the ACTIONcolumn
SERIALIZABLE_ABORTS	NUMBER	Number of times the transaction fails to serialize, producing ORA-08177 errors, totalled over all the child cursors
CPU_TIME	NUMBER	CPU time (in microseconds) used by this cursor for parsing/executing/fetching
ELAPSED_TIME	NUMBER	Elapsed time (in microseconds) used by this cursor for parsing/executing/fetching
IS_OBSOLETE	VARCHAR2(1)	Indicates whether the cursor has become obsolete (Y ) or not (N ). This can happen if the number of child cursors is too large.
CHILD_LATCH	NUMBER	Child latch number that is protecting the cursor
PROGRAM_ID	NUMBER	Program identifie