如何监控oracle的索引是否使用.docx

如何监控oracle的索引是否使用 很多软件开发过程中，没有注意合理规划索引，造成一个表上有N多个索引，为后续的维护和优化带来麻烦。因此有时候需要监控已有的索引是否在使用，oracle提供了监控索引是否使用的工具，很简单，简要介绍一下。首先，我们如果是监控一个表上的所有索引，可以这样先生成监控的命令：SQL select alter index |index_name| monitoring usage; from user_indexes where table_name=upper(mpaymentappl)；ALTERINDEX|INDEX_NAME|MONITORINGUSAGE;-alter index IDX_MPAYMENTAPPL_BCODE monitoring usage;alter index MPAYMENTAPPL_FLAGS monitoring usage;alter index MPAYMENTAPPL_PAICODE monitoring usage;然后执行这些脚本就开始监控了，监控信息可通过V$OBJECT_USAGE查看，通过used列可知道这个索引是否被使用：SQL select * from V$OBJECT_USAGE；INDEX_NAME TABLE_NAME MON USE START_MONITORING END_MONITORING- - - - - -IDX_MPAYMENTAPPL_BCODE MPAYMENTAPPL YES NO 03/24/2010 10:55:27MPAYMENTAPPL_FLAGS MPAYMENTAPPL YES NO 03/24/2010 10:55:27MPAYMENTAPPL_PAICODE MPAYMENTAPPL YES NO 03/24/2010 10:55:28取消监控某个索引：SQL ALTER INDEX MPAYMENTAPPL_FLAGS NOMONITORING USAGE;Index altered.SQL select * from V$OBJECT_USAGE2 /INDEX_NAME TABLE_NAME MON USE START_MONITORING END_MONITORING- - - - - -IDX_MPAYMENTAPPL_BCODE MPAYMENTAPPL YES NO 03/24/2010 10:55:27MPAYMENTAPPL_FLAGS MPAYMENTAPPL NO NO 03/24/2010 10:55:27 03/24/2010 10:57:19MPAYMENTAPPL_PAICODE MPAYMENTAPPL YES NO 03/24/2010 10:55:28那些持续关注一定时间没有使用的索引就可以删除了，以提高DML操作效率实际工作中，我们可以选择暂时禁用索引功能，来提高数据表插入、修改效率。因为，在索引起作用的情况下，大量数据的DML操作会带来很多的索引更新和Redo Log的生成。这在批量数据加载的时候是不需要的。所以，可以暂时禁用索引。/Oracle常用监控SQL2012-06-14 11:39:34|分类：oracle技术|举报|字号订阅1.监控事例的等待：select event,sum(decode(wait_time,0,0,1) prev, sum(decode(wait_time,0,1,0) curr,count(*) from v$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$filestat f,dba_data_files dfwhere f.file#=df.file_id4.监空文件系统的I/O比例：select substr(a.file#,1,2) #,substr(,1,30) name,a.status,a.bytes,b.phyrds,b.phywrtsfrom v$datafile a,v$filestat bwhere a.file#=b.file#5.在某个用户下找所有的索引：select user_indexes.table_name, user_indexes.index_name,uniqueness,column_namefrom user_ind_columns, user_indexeswhere user_ind_columns.index_name = user_indexes.index_nameand user_ind_columns.table_name = user_indexes.table_nameorder by user_indexes.table_type, user_indexes.table_name,user_indexes.index_name, column_position;6. 监控 SGA 的命中率select a.value + b.value logical_reads, c.value phys_reads,round(100 * (a.value+b.value)-c.value) / (a.value+b.value) BUFFER HIT RATIOfrom v$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 ratiofrom 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 percentfrom 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 MISSESFROM V$ROWCACHE14. 找ORACLE字符集select * from ps$ 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_