oracle 性能监控 sql

性能监控之监控SQL语句
 
分析表
analyze TABLE tablename compute statistics FOR ALL indexes;
analyze TABLE tablename compute statistics FOR ALL indexed COLUMNS;
analyze TABLE tablename compute statistics FOR TABLE;
 
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_Wait
GROUP BY event ORDER BY 4;
 
查看碎片程度高的表
 
SELECT segment_name table_name , COUNT(*) extents
FROM dba_segments WHERE owner NOT IN (SYS, SYSTEM) GROUP BY segment_name
HAVING COUNT(*) = (SELECT MAX( COUNT(*) FROM dba_segments GROUP BY segment_name);
 
表、索引的存储情况检查
 
SELECT segment_name,sum(bytes),count(*) ext_quan FROM dba_extents WHERE
tablespace_name=&tablespace_name AND segment_type=TABLE GROUP BY tablespace_name,segment_name;
 
SELECT segment_name,count(*) FROM dba_extents WHERE segment_type=INDEX AND owner=&owner
GROUP BY segment_name;
 
找使用CPU多的用户session
 
12是cpu used BY this session
 
SELECT a.sid,spid,STATUS,substr(a.program,1,40) prog,a.terminal,osuser,value/60/100 value
FROM v$session a,v$process b,v$sesstat c
WHERE c.statistic#=12 and c.sid=a.sid and a.paddr=b.addr order by value desc;
 
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 pbw
FROM v$filestat f, dba_data_files df
WHERE f.file# = df.file_id
ORDER BY df.tablespace_name;
 
 
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;
 
在某个用户下找所有的索引
 
SELECT user_indexes.table_name, user_indexes.index_name,uniqueness, column_name
FROM user_ind_columns, user_indexes
WHERE user_ind_columns.index_name = user_indexes.index_name
AND user_ind_columns.table_name = user_indexes.table_name
ORDER BY user_indexes.table_type, user_indexes.table_name,
user_indexes.index_name, column_position;
 
 
监控文件系统的 I/O 比例
 
SELECT substr(a.file#,1,2) "#", substr(a.name,1,30) "Name",
a.STATUS, a.bytes, b.phyrds, b.phywrts
FROM v$datafile a, v$filestat b
WHERE a.file# = b.file#;
 
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$rowcache
WHERE gets+getmisses <>0
GROUP BY parameter, gets, getmisses;
 
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 libcache
FROM v$librarycache;
 
SELECT sum(pinhits-reloads)/sum(pins) "hit radio",sum(reloads)/sum(pins) "reload percent"
FROM v$librarycache;
 
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 c
WHERE a.statistic# = 38 and b.statistic# = 39
AND c.statistic# = 40;
 
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) ratio2
FROM v$latch WHERE name IN (redo allocation, redo copy);
 
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_required
FROM dba_object_size
GROUP BY type ORDER BY 2;
 
监控内存和硬盘的排序比率，最好使它小于 .10，增加 sort_area_size
 
SELECT name, value FROM v$sysstat WHERE name IN (sorts (memory), sorts (disk));
 
 
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 b
WHERE a.sql_address =b.address ORDER BY address, piece;
 
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
 
监控 MTS
 
SELECT 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
 
碎片程度
 
SELECT tablespace_name,count(tablespace_name) FROM dba_free_space GROUP BY tablespace_name
HAVING count(tablespace_name)>10;
 
ALTER tablespace name coalesce;
ALTER TABLE name deallocate unused;
 
CREATE OR REPLACE VIEW ts_blocks_v AS
SELECT tablespace_name,block_id,bytes,blocks,free space segment_name FROM dba_free_space
union ALL
SELECT tablespace_name,block_id,bytes,blocks,segment_name FROM dba_extents;
 
SELECT * FROM ts_blocks_v;
 
SELECT tablespace_name,sum(bytes),max(bytes),count(block_id) FROM dba_free_space
GROUP BY tablespace_name;