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(*) from v$session_wait group by event order by 4;2.回滚段的争用情况：select name,waits,gets,waits/gets ratio from v$rollstat a,v$rollname b where a.usn=b.usn;3.监控表空间的I/O比例：select df.tablespace_name name,df.file_name "ile",f.phyrds pyr,f.phyblkrd pbr,f.phywrts pyw,f.phyblkwrt pbwfrom v$filestat f,dba_data_files dfwhere f.file#=df.file_id4.监空文件系统的I/O比例：select substr(a.file#,1,2) "#",substr(a.name,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_nameand user_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$sysstat cwhere a.statistic# = 38 and b.statistic# = 39and c.statistic# = 40;7. 监控 SGA 中字典缓冲区的命中率select parameter, gets,Getmisses , getmisses/(gets+getmisses)*100 "miss ratio",(1-(sum(getmisses)/ (sum(gets)+sum(getmisses))))*100 "Hit ratio"from v$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 count(name) num_instances ,type ,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 type order by 2;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$latch WHERE name IN ('redo allocation', 'redo copy');11. 监控内存和硬盘的排序比率，最好使它小于 .10，增加 sort_area_sizeSELECT name, value FROM v$sysstat WHERE 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_text from 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" FROMV$LIBRARYCACHE;SELECT (SUM(GETS - GETMISSES - USAGE - FIXED)) / SUM(GETS) "ROWCACHE" FROM V$ROWCACHE;SELECT SUM(PINS) "EXECUTIONS", SUM(RELOADS) "CACHE MISSESWHILE EXECUTING" FROM V$LIBRARYCACHE;后者除以前者,此比率小于1%,接近0%为好。SELECT SUM(GETS) "DICTIONARY GETS",SUM(GETMISSES)"DICTIONARY CACHE GET MISSES"FROM V$ROWCACHE14. 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$dispatcher;此值大于0.5时，参数需加大select sum(wait)/sum(totalq) "ispatcher waits" from v$queue wheretype='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,'free space' segment_namefrom dba_free_spaceunion allselect tablespace_name,block_id,bytes,blocks,segment_name fromdba_extents;select * from ts_blocks_v;select tablespace_name,sum(bytes),max(bytes),count(block_id) fromdba_free_spacegroup by tablespace_name;查看碎片程度高的表SELECT segment_name table_name , COUNT(*) extentsFROM dba_segments WHERE owner NOT IN ('SYS', 'SYSTEM') GROUP BYsegment_nameHAVING COUNT(*) = (SELECT MAX( COUNT(*) ) FROM dba_segmentsGROUP BY segment_name);17. 表、索引的存储情况检查select segment_name,sum(bytes),count(*) ext_quan from dba_extentswheretablespace_name='&tablespace_name' and segment_type='TABLE' group bytablespace_name,segment_name;select segment_name,count(*) from dba_extents wheresegment_type='INDEX' and wner='&wner'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$sesstat cwhere c.statistic#=12 and c.sid=a.sid and a.paddr=b.addr order by valuedesc;20.监控log_buffer的使用情况：(值最好小于1%，否则增加log_buffer 的大小)select rbar.name,rbar.value,re.name,re.value,(rbar.value*100)/re.value||'%' "radio"from v$sysstat rbar,v$sysstat rewhere rbar.name='redo buffer allocation retries'and re.name='redo entries';转载自：http://space.itpub.net/?uid-27038344-action-viewspace-itemid-732080#xspace-itemreply19、查看运行过的SQL语句：SELECT SQL_TEXTFROM V$SQL20.如果所表，解除锁表select b.sid,b.machine,c.object_name,a.oracle_username, a.locked_mode,b.osuser,b.SERIAL#from v$locked_object a,v$session b,all_objects cwhere a.session_id=b.sid and a.object_id=c.object_id;alter system kill session '58,900';58=sid900=SERIAL#
