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性能监控之监控SQL语句
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分析表
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analyze TABLE tablename compute statistics FOR ALL indexes;
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analyze TABLE tablename compute statistics FOR ALL indexed COLUMNS;
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analyze TABLE tablename compute statistics FOR TABLE;
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监控事例的等待
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SELECT event,sum(decode(wait_Time,0,0,1)) "Prev",
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sum(decode(wait_Time,0,1,0)) "Curr",count(*) "Tot"
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FROM v$session_Wait
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GROUP BY event ORDER BY 4;
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查看碎片程度高的表
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SELECT segment_name table_name , COUNT(*) extents
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FROM dba_segments WHERE owner NOT IN (SYS, SYSTEM) GROUP BY segment_name
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HAVING COUNT(*) = (SELECT MAX( COUNT(*) FROM dba_segments GROUP BY segment_name);
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表、索引的存储情况检查
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SELECT segment_name,sum(bytes),count(*) ext_quan FROM dba_extents WHERE
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tablespace_name=&tablespace_name AND segment_type=TABLE GROUP BY tablespace_name,segment_name;
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SELECT segment_name,count(*) FROM dba_extents WHERE segment_type=INDEX AND owner=&owner
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GROUP BY segment_name;
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找使用CPU多的用户session
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12是cpu used BY this session
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SELECT a.sid,spid,STATUS,substr(a.program,1,40) prog,a.terminal,osuser,value/60/100 value
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FROM v$session a,v$process b,v$sesstat c
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WHERE c.statistic#=12 and c.sid=a.sid and a.paddr=b.addr order by value desc;
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监控表空间的 I/O 比例
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SELECT df.tablespace_name name,df.file_name "file",f.phyrds pyr,
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f.phyblkrd pbr,f.phywrts pyw, f.phyblkwrt pbw
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FROM v$filestat f, dba_data_files df
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WHERE f.file# = df.file_id
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ORDER BY df.tablespace_name;
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回滚段的争用情况
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SELECT name, waits, gets, waits/gets "Ratio"
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FROM v$rollstat a, v$rollname b
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WHERE a.usn = b.usn;
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在某个用户下找所有的索引
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SELECT user_indexes.table_name, user_indexes.index_name,uniqueness, column_name
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FROM user_ind_columns, user_indexes
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WHERE user_ind_columns.index_name = user_indexes.index_name
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AND user_ind_columns.table_name = user_indexes.table_name
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ORDER BY user_indexes.table_type, user_indexes.table_name,
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user_indexes.index_name, column_position;
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监控文件系统的 I/O 比例
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SELECT substr(a.file#,1,2) "#", substr(a.name,1,30) "Name",
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a.STATUS, a.bytes, b.phyrds, b.phywrts
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FROM v$datafile a, v$filestat b
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WHERE a.file# = b.file#;
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监控 SGA 中字典缓冲区的命中率
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SELECT parameter, gets,Getmisses , getmisses/(gets+getmisses)*100 "miss ratio",
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(1-(sum(getmisses)/ (sum(gets)+sum(getmisses))))*100 "Hit ratio"
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FROM v$rowcache
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WHERE gets+getmisses <>0
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GROUP BY parameter, gets, getmisses;
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监控 SGA 中共享缓存区的命中率,应该小于1%
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SELECT sum(pins) "Total Pins", sum(reloads) "Total Reloads",
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sum(reloads)/sum(pins) *100 libcache
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FROM v$librarycache;
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SELECT sum(pinhits-reloads)/sum(pins) "hit radio",sum(reloads)/sum(pins) "reload percent"
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FROM v$librarycache;
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监控 SGA 的命中率
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SELECT a.value + b.value "logical_reads", c.value "phys_reads",
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round(100 * ((a.value+b.value)-c.value) / (a.value+b.value)) "BUFFER HIT RATIO"
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FROM v$sysstat a, v$sysstat b, v$sysstat c
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WHERE a.statistic# = 38 and b.statistic# = 39
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AND c.statistic# = 40;
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监控 SGA 中重做日志缓存区的命中率,应该小于1%
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SELECT name, gets, misses, immediate_gets, immediate_misses,
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Decode(gets,0,0,misses/gets*100) ratio1,
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Decode(immediate_gets+immediate_misses,0,0,
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immediate_misses/(immediate_gets+immediate_misses)*100) ratio2
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FROM v$latch WHERE name IN (redo allocation, redo copy);
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显示所有数据库对象的类别和大小
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SELECT count(name) num_instances ,type ,sum(source_size) source_size ,
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sum(parsed_size) parsed_size ,sum(code_size) code_size ,sum(error_size) error_size,
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sum(source_size) +sum(parsed_size) +sum(code_size) +sum(error_size) size_required
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FROM dba_object_size
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GROUP BY type ORDER BY 2;
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监控内存和硬盘的排序比率,最好使它小于 .10,增加 sort_area_size
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SELECT name, value FROM v$sysstat WHERE name IN (sorts (memory), sorts (disk));
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监控当前数据库谁在运行什么SQL语句
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SELECT osuser, username, sql_text FROM v$session a, v$sqltext b
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WHERE a.sql_address =b.address ORDER BY address, piece;
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监控字典缓冲区
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SELECT (SUM(PINS - RELOADS)) / SUM(PINS) "LIB CACHE" FROM V$LIBRARYCACHE;
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SELECT (SUM(GETS - GETMISSES - USAGE - FIXED)) / SUM(GETS) "ROW CACHE" FROM V$ROWCACHE;
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SELECT SUM(PINS) "EXECUTIONS", SUM(RELOADS) "CACHE MISSES WHILE EXECUTING" FROM V$LIBRARYCACHE;
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后者除以前者,此比率小于1%,接近0%为好。
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SELECT SUM(GETS) "DICTIONARY GETS",SUM(GETMISSES) "DICTIONARY CACHE GET MISSES"
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FROM V$ROWCACHE
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监控 MTS
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SELECT busy/(busy+idle) "shared servers busy" FROM v$dispatcher;
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此值大于0.5时,参数需加大
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SELECT sum(wait)/sum(totalq) "dispatcher waits" FROM v$queue WHERE type=dispatcher;
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SELECT count(*) FROM v$dispatcher;
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SELECT servers_highwater FROM v$mts;
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servers_highwater接近mts_max_servers时,参数需加大
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碎片程度
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SELECT tablespace_name,count(tablespace_name) FROM dba_free_space GROUP BY tablespace_name
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HAVING count(tablespace_name)>10;
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ALTER tablespace name coalesce;
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ALTER TABLE name deallocate unused;
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CREATE OR REPLACE VIEW ts_blocks_v AS
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SELECT tablespace_name,block_id,bytes,blocks,free space segment_name FROM dba_free_space
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union ALL
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SELECT tablespace_name,block_id,bytes,blocks,segment_name FROM dba_extents;
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SELECT * FROM ts_blocks_v;
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SELECT tablespace_name,sum(bytes),max(bytes),count(block_id) FROM dba_free_space
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GROUP BY tablespace_name;
oracle 性能监控 sql
最新推荐文章于 2023-05-29 10:22:29 发布
