监控数据库性能的SQL语句1. 监控事例的等待select event,sum(decode(wait_Time,0,0,1)) "Prev",sum(decode(wait_Time,0,1,0)) "Curr",count(*) "Tot"from v$session_Waitgroup by eventorder by 4;2. 回滚段的争用情况select name, waits, gets, waits/gets "Ratio"from v$rollstat a, v$rollname bwhere n = n;3. 监控表空间的 I/O 比例select df.tablespace_name name,df.file_name "file",f.phyrds pyr, f.phyblkrd pbr,f.phywrts pyw, f.phyblkwrt pbwfrom v$filestat f, dba_data_files dfwhere f.file# = df.file_idorder by df.tablespace_name;4. 监控文件系统的 I/O 比例select substr(a.file#,1,2) "#", substr(,1,30) "Name",a.status, a.bytes,b.phyrds, b.phywrtsfrom v$datafile a, v$filestat bwhere a.file# = b.file#;5.在某个用户下找所有的索引select user_indexes.table_name,user_indexes.index_name,uniqueness,column_namefrom user_ind_columns, user_indexeswhere user_ind_columns.index_name =user_indexes.index_name anduser_ind_columns.table_name = user_indexes.table_nameorder by user_indexes.table_type, user_indexes.table_name,user_indexes.index_name, column_position;6. 监控 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$sysstat cwhere a.statistic# = 38 and b.statistic# = 39 andc.statistic# = 40;7. 监控 SGA 中字典缓冲区的命中率select parameter, gets,Getmisses ,getmisses/(gets+getmisses)*100 "miss ratio",(1-(sum(getmisses)/ (sum(gets)+sum(getmisses))))*100 "Hit ratio"from v$rowcachewhere gets+getmisses <>0group by parameter, gets, getmisses;8. 监控 SGA 中共享缓存区的命中率，应该小于1%select sum(pins) "Total Pins", sum(reloads) "Total Reloads",sum(reloads)/sum(pins) *100 libcachefrom v$librarycache;select sum(pinhits-reloads)/sum(pins) "hit radio",sum(reloads)/sum(pins) "reload percent"from v$librarycache;9. 显示所有数据库对象的类别和大小select type,count(name) num_instances,sum(source_size) source_size,sum(parsed_size) parsed_size,sum(code_size) code_size,sum(error_size) error_size,sum(source_size) +sum(parsed_size) +sum(code_size) +sum(error_size) size_requiredfrom dba_object_sizegroup by typeorder by 1;10. 监控 SGA 中重做日志缓存区的命中率，应该小于1%SELECT name, gets, misses, immediate_gets, immediate_misses,Decode(gets,0,0,misses/gets*100) ratio1,Decode(immediate_gets+immediate_misses,0,0,immediate_misses/(immediate_gets+immediate_misses)*100) ratio2FROM v$latchWHERE name IN ('redo allocation', 'redo copy');11. 监控内存和硬盘的排序比率，最好使它小于.10，增加sort_area_sizeSELECT name, valueFROM v$sysstatWHERE name IN ('sorts (memory)', 'sorts (disk)');12. 监控当前数据库谁在运行什么SQL语句SELECT osuser, username, sql_textfrom v$session a, v$sqltext bwhere a.sql_address =b.address order by address, piece;13. 监控字典缓冲区SELECT (SUM(PINS - RELOADS)) / SUM(PINS) "LIB CACHE"FROM V$LIBRARYCACHE;SELECT (SUM(GETS - GETMISSES - USAGE - FIXED)) / SUM(GETS) "ROW CACHE"FROM V$ROWCACHE;SELECT SUM(PINS) "EXECUTIONS", SUM(RELOADS) "CACHE MISSES WHILE EXECUTING"FROM V$LIBRARYCACHE;后者除以前者,此比率小于1%,接近0%为好。

SELECT SUM(GETS) "DICTIONARY GETS",SUM(GETMISSES) "DICTIONARY CACHE GET MISSES"FROM V$ROWCACHE;14. 找ORACLE字符集select * from sys.props$ where name='NLS_CHARACTERSET'; 15. 监控 MTSselect busy/(busy+idle) "shared servers busy" from v$dispatcher;此值大于0.5时，参数需加大select sum(wait)/sum(totalq) "dispatcher waits" from v$queue where type='dispatcher';select count(*) from v$dispatcher;select servers_highwater from v$mts;servers_highwater接近mts_max_servers时，参数需加大16. 碎片程度select tablespace_name,count(tablespace_name)from dba_free_spacegroup by tablespace_namehaving count(tablespace_name)>10;alter tablespace name coalesce;alter table name deallocate unused;create or replace view ts_blocks_v asselect tablespace_name,block_id,bytes,blocks,segment_namefrom dba_free_spaceunion allselect tablespace_name,block_id,bytes,blocks,segment_namefrom dba_extents;select * from ts_blocks_v;select tablespace_name,sum(bytes),max(bytes),count(block_id)from dba_free_spacegroup by tablespace_name;查看碎片程度高的表SELECT segment_name table_name , COUNT(*) extentsFROM dba_segmentsWHERE owner NOT IN ('SYS', 'SYSTEM')GROUP BY segment_nameHAVING COUNT(*) = (SELECT MAX(COUNT(*)) FROM dba_segments GROUP BY segment_name);17. 表、索引的存储情况检查select segment_name,sum(bytes),count(*) ext_quanfrom dba_extentswhere tablespace_name='&tablespace_name' andsegment_type='TABLE'group by tablespace_name,segment_name;select segment_name,count(*)from dba_extentswhere segment_type='INDEX' and owner='&owner'group by segment_name;18、找使用CPU多的用户session12是cpu used by this sessionselect a.sid,spid,status,substr(a.program,1,40) prog,a.terminal,osuser,value/60/100 valuefrom v$session a,v$process b,v$sesstat cwhere c.statistic#=12 andc.sid=a.sid anda.paddr=b.addrorder by value desc;19.对可疑/性能不好的Server Process来进行Trace.,可以用tkprof来分析Trace的结果.比较方便.使用Unix的KSH.(1) start_trc:#!/bin/kshif (( $# != 1 ))thenecho Usuage: start_trc pidfisid_serial=$(print "connect / as sysdba;set heading off;set feedback off;select a.sid,a.serial# from v\$session a,v\$process b where a.paddr=b.addr and b.spid=$1;exit;" | sqlplus -s /nolog | grep -v 'Connected' | sed -e 's/\([0-9]\ {1,\}\)/\1,/' -e '/^$/d' )if [[ -z $sid_serial ]]thenprint "Seems that this process $1 is not an Oracle process!"exit 1fiprint "connect / as sysdba;execute dbms_system.set_sql_trace_in_session($sid_serial,true); exit;" | sqlplus -s /nolog(2) stop_trc:#!/bin/kshif (( $# != 1 ))thenecho Usuage: stop_trc pidfisid_serial=$(print "connect / as sysdba;set heading off;set feedback off;select a.sid,a.serial# from v\$session a,v\$process b where a.paddr=b.addr and b.spid=$1;exit;" | sqlplus -s /nolog | grep -v 'Connected' | sed -e 's/\([0-9]\ {1,\}\)/\1,/' -e '/^$/d' )if [[ -z $sid_serial ]]thenprint "Seems that this process $1 is not an Oracle process!"exit 1fiprint "connect / as sysdba;execute dbms_system.set_sql_trace_in_session($sid_serial,false); exit;" | sqlplus -s /nolog20.查看LockSELECT ername, m.sid, m.type,DECODE(m.lmode, 0, 'None',1, 'Null',2, 'Row Share',3, 'Row Excl.',4, 'Share',5, 'S/Row Excl.',6, 'Exclusive',lmode, ltrim(to_char(lmode,'990'))) lmode,DECODE(m.request,0, 'None',1, 'Null',2, 'Row Share',3, 'Row Excl.',4, 'Share',5, 'S/Row Excl.',6, 'Exclusive',request, ltrim(to_char(m.request,'990'))) request, m.id1, m.id2FROM v$session sn, v$lock mWHERE (sn.sid = m.sid AND m.request != 0) OR ( sn.sid = m.sid ANDm.request = 0 ANDlmode != 4 AND(id1, id2) IN (SELECT s.id1, s.id2FROM v$lock sWHERE request != 0 ANDs.id1 = m.id1 ANDs.id2 = m.id2))ORDER BY id1, id2, m.request;select l.sid,s.serial#,ername,s.terminal,decode(l.type,'RW','RW - Row Wait Enqueue','TM','TM - DML Enqueue','TX','TX - Trans Enqueue','UL','UL - User',l.type||'System') res,substr(,1,10) tab, owner,l.id1,l.id2,decode(l.lmode,1,'No Lock',2,'Row Share',3,'Row Exclusive',4,'Share',5,'Shr Row Excl',6,'Exclusive',null) lmode,decode(l.request,1,'No Lock',2,'Row Share',3,'Row Excl',4,'Share',5,'Shr Row Excl',6,'Exclusive',null) requestfrom v$lock l, v$session s,er$ u,sys.obj$ twhere l.sid = s.sid ands.type != 'BACKGROUND' and t.obj# = l.id1 ander# = t.owner#;。