知识大全 Oracle数据库维护常用SQL语句集合（3）

Posted 2022-07-15 知

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　　性能相关内容

　　捕捉运行很久的SQL column username format a column opname format a column progress format a SELECT Username Sid Opname Round(Sofar * / Totalwork ) || % AS Progress Time_Remaining Sql_Text FROM V$session_Longops V$sql WHERE Time_Remaining <> AND Sql_Address = Address AND Sql_Hash_Value = Hash_Value;

　　求DISK READ较多的SQL SELECT St Sql_Text FROM V$sql s V$sqltext St WHERE s Address = St Address AND s Hash_Value = St Hash_Value AND s Disk_Reads > ;

　　求DISK SORT严重的SQL SELECT Sess Username SQL Sql_Text Sort Blocks FROM V$session Sess V$sqlarea SQL V$sort_Usage Sort WHERE Sess Serial# = Sort Session_Num AND Sort Sqladdr = SQL Address AND Sort Sqlhash = SQL Hash_Value AND Sort Blocks > ;

　　监控索引是否使用 alter index &index_name monitoring usage; alter index &index_name nomonitoring usage; select * from v$object_usage where index_name = &index_name;

　　求数据文件的I/O分布 SELECT Df NAME Phyrds Phywrts Phyblkrd Phyblkwrt Singleblkrds Readtim Writetim FROM V$filestat Fs V$dbfile Df WHERE Fs File# = Df File# ORDER BY Df NAME;

　　查看还没提交的事务 select * from v$locked_object; select * from v$transaction;

　　回滚段查看 SELECT Rownum Sys Dba_Rollback_Segs Segment_Name NAME V$rollstat Extents Extents V$rollstat Rssize Size_In_Bytes V$rollstat Xacts Xacts V$rollstat Gets Gets V$rollstat Waits Waits V$rollstat Writes Writes Sys Dba_Rollback_Segs Status Status FROM V$rollstat Sys Dba_Rollback_Segs V$rollname WHERE V$rollname NAME(+) = Sys Dba_Rollback_Segs Segment_Name AND V$rollstat Usn(+) = V$rollname Usn ORDER BY Rownum

　　查看系统请求情况 SELECT Decode(NAME summed dirty write queue length VALUE) / Decode(NAME write requests VALUE) Write Request Length FROM V$sysstat WHERE NAME IN ( summed dirty queue length write requests ) AND VALUE > ;

　　计算data buffer 命中率 SELECT a VALUE + b VALUE logical_reads c VALUE phys_reads Round( * ((a VALUE + b VALUE) c VALUE) / (a VALUE + b VALUE)) BUFFER HIT RATIO FROM V$sysstat a V$sysstat b V$sysstat c WHERE a Statistic# = AND b Statistic# = AND c Statistic# = ; SELECT NAME ( (Physical_Reads / (Db_Block_Gets + Consistent_Gets))) * h_Ratio FROM V$buffer_Pool_Statistics;

　　查看内存使用情况 SELECT Least(MAX(b VALUE) / ( * ) SUM(a Bytes) / ( * )) Shared_Pool_Used MAX(b VALUE) / ( * ) Shared_Pool_Size Greatest(MAX(b VALUE) / ( * ) SUM(a Bytes) / ( * )) (SUM(a Bytes) / ( * )) Shared_Pool_Avail ((SUM(a Bytes) / ( * )) / (MAX(b VALUE) / ( * ))) * Avail_Pool_Pct FROM V$sgastat a V$parameter b WHERE (a Pool = shared pool AND a NAME NOT IN ( free memory )) AND b NAME = shared_pool_size ;

　　查看用户使用内存情况

　　 SELECT Username SUM(Sharable_Mem) SUM(Persistent_Mem) SUM(Runtime_Mem) FROM Sys v_$sqlarea a Dba_Users b WHERE a Parsing_User_Id = b User_Id GROUP BY Username;

　　查看对象的缓存情况 SELECT Owner Namespace TYPE NAME Sharable_Mem Loads Executions Locks Pins Kept FROM V$db_Object_Cache WHERE TYPE NOT IN ( NOT LOADED NON EXISTENT VIEW TABLE SEQUENCE ) AND Executions > AND Loads > AND Kept = NO ORDER BY Owner Namespace TYPE Executions DESC; SELECT TYPE COUNT(*) FROM V$db_Object_Cache GROUP BY TYPE;

　　查看库缓存命中率 SELECT Namespace Gets Gethitratio * Gethitratio Pins Pinhitratio * Pinhitratio Reloads Invalidations FROM V$librarycache

　　查看某些用户的hash SELECT a Username COUNT(b Hash_Value) Total_Hash COUNT(b Hash_Value) COUNT(UNIQUE(b Hash_Value)) Same_Hash (COUNT(UNIQUE(b Hash_Value)) / COUNT(b Hash_Value)) * u_Hash_Ratio FROM Dba_Users a V$sqlarea b WHERE a User_Id = b Parsing_User_Id GROUP BY a Username;

　　查看字典命中率 SELECT (SUM(Getmisses) / SUM(Gets)) Ratio FROM V$rowcache;

　　查看undo段的使用情况 SELECT d Segment_Name Extents Optsize Shrinks Aveshrink Aveactive d Status FROM V$rollname n V$rollstat s Dba_Rollback_Segs d WHERE d Segment_Id = n Usn(+) AND d Segment_Id = s Usn(+);

　　求归档日志的切换频率(生产系统可能时间会很长) SELECT Start_Recid Start_Time End_Recid End_Time Minutes FROM (SELECT Test * Rownum AS Rn FROM (SELECT b Recid Start_Recid To_Char(b First_Time yyyy mm dd hh :mi:ss ) Start_Time a Recid End_Recid To_Char(a First_Time yyyy mm dd hh :mi:ss ) End_Time Round(((a First_Time b First_Time) * ) * ) Minutes FROM V$log_History a V$log_History b WHERE a Recid = b Recid + AND b First_Time > SYSDATE ORDER BY a First_Time DESC) Test) y WHERE y Rn <

　　求回滚段正在处理的事务 SELECT a NAME b Xacts c Sid c Serial# d Sql_Text FROM V$rollname a V$rollstat b V$session c V$sqltext d V$transaction e WHERE a Usn = b Usn AND b Usn = e Xidusn AND c Taddr = e Addr AND c Sql_Address = d Address AND c Sql_Hash_Value = d Hash_Value ORDER BY a NAME c Sid d Piece;

　　求某个事务的重做信息(bytes) SELECT s NAME m VALUE FROM V$mystat m V$statname s WHERE m Statistic# = s Statistic# AND s NAME LIKE %redo size% ;

　　求cache中缓存超过其 %的对象 SELECT o Owner o Object_Type o Object_Name COUNT(b Objd) FROM V$bh b Dba_Objects o WHERE b Objd = o Object_Id GROUP BY o Owner o Object_Type o Object_Name HAVING COUNT(b Objd) > (SELECT To_Number(VALUE) * FROM V$parameter WHERE NAME = db_block_buffers );

　　求buffer cache中的块信息

　　 SELECT o Object_Type Substr(o Object_Name ) Objname b Objd b Status COUNT(b Objd) FROM V$bh b Dba_Objects o WHERE b Objd = o Data_Object_Id AND o Owner = &owner GROUP BY o Object_Type o Object_Name b Objd b Status;

　　求日志文件的空间使用 SELECT Le Leseq Current_Log_Sequence# * Cp Cpodr_Bno / Le Lesiz Percentage_Full FROM X$kcccp Cp X$kccle Le WHERE Le Leseq = Cp Cpodr_Seq;

　　求等待中的对象 SELECT /*+rule */ s Sid s Username w Event o Owner o Segment_Name o Segment_Type o Partition_Name w Seconds_In_Wait Seconds w State FROM V$session_Wait w V$session s Dba_Extents o WHERE w Event IN (SELECT NAME FROM V$event_Name WHERE Parameter = file# AND Parameter = block# AND NAME NOT LIKE control% ) AND o Owner <> sys AND w Sid = s Sid AND w P = o File_Id AND w P >= o Block_Id AND w P < o Block_Id + o Blocks

　　求当前事务的重做尺寸 SELECT V$statname NAME VALUE FROM V$mystat V$statname WHERE V$mystat Statistic# = V$statname Statistic# AND V$statname NAME = redo size ;

　　唤醒smon去清除临时段 column pid new_value Smon set termout off SELECT p Pid FROM Sys v_$bgprocess b Sys v_$process p WHERE b NAME = SMON AND p Addr = b Paddr; SET Termout ON Oradebug Wakeup &Smon Undefine Smon

　　求回退率 SELECT b VALUE / (a VALUE + b VALUE) a VALUE b VALUE FROM V$sysstat a V$sysstat b WHERE a Statistic# = AND b Statistic# = ;

　　求free memory SELECT * FROM V$sgastat WHERE NAME = free memory ; SELECT a NAME SUM(b VALUE) FROM V$statname a V$sesstat b WHERE a Statistic# = b Statistic# GROUP BY a NAME;

　　查看一下谁在使用那个可以得回滚段或者查看一下某个可以得用户在使用回滚段

　　找出领回滚段不断增长的事务再看看如何处理它是否可以将它mit 再不行

　　就看看能否kill它等等查看当前正在使用的回滚段的用户信息和回滚段信息: set linesize SELECT r NAME ROLLBACK SEGMENT NAME l Sid ORACLE PID p Spid SYSTEM PID s Username ORACLE USERNAME FROM V$lock l V$process p V$rollname r V$session s WHERE l Sid = p Pid(+) AND s Sid = l Sid AND Trunc(l Id (+) / ) = r Usn AND l TYPE(+) = TX AND l Lmode(+) = ORDER BY r NAME;

　　查看用户的回滚段的信息 SELECT s Username Rn NAME FROM V$session s V$transaction t V$rollstat r V$rollname Rn WHERE s Saddr = t Ses_Addr AND t Xidusn = r Usn AND r Usn = Rn Usn

　　查看内存中存的使用

　　SELECT Decode(Greatest(CLASS ) Decode(CLASS Data Sort Header To_Char(CLASS)) Rollback ) Class SUM(Decode(Bitand(Flag ) )) Not Dirty SUM(Decode(Bitand(Flag ) )) Dirty SUM(Dirty_Queue) On Dirty COUNT(*) Total FROM X$bh GROUP BY Decode(Greatest(CLASS ) Decode(CLASS Data Sort Header To_Char(CLASS)) Rollback );

cha138/Article/program/Oracle/201311/17840