--监控索引是否使用
alter index &index_name monitoring usage;
alter index &index_name nomonitoring usage;
select * from v$object_usage where index_name = &index_name;
--求数据文件的I/O分布
select df.name,phyrds,phywrts,phyblkrd,phyblkwrt,singleblkrds,readtim,writetim
from v$filestat fs,v$dbfile df
where fs.file#=df.file# order by df.name;
--求某个隐藏参数的值
col ksppinm format a54
col ksppstvl format a54
select ksppinm, ksppstvl
from x$ksppi pi, x$ksppcv cv
where cv.indx=pi.indx and pi.ksppinm like '/_%' escape '/' and pi.ksppinm like '%meer%';
--求系统中较大的latch
select name,sum(gets),sum(misses),sum(sleeps),sum(wait_time)
from v$latch_children
group by name having sum(gets) > 50 order by 2;
--求归档日志的切换频率(生产系统可能时间会很长)
select start_recid,start_time,end_recid,end_time,minutes from (select test.*, rownum as rn
from (select b.recid start_recid,to_char(b.first_time,'yyyy-mm-dd hh24:mi:ss') start_time,
a.recid end_recid,to_char(a.first_time,'yyyy-mm-dd hh24:mi:ss') end_time,round(((a.first_time-b.first_time)*24)*60,2) minutes
from v$log_history a,v$log_history b where a.recid=b.recid+1 and b.first_time > sysdate - 1
order by a.first_time desc) test) y where y.rn < 30
--求回滚段正在处理的事务
select a.name,b.xacts,c.sid,c.serial#,d.sql_text
from v$rollname a,v$rollstat b,v$session c,v$sqltext d,v$transaction e
where a.usn=b.usn and b.usn=e.xidusn and c.taddr=e.addr
and c.sql_address=d.address and c.sql_hashvalue=d.hash_value order by a.name,c.sid,d.piece;
--求出无效的对象
select 'alter procedure '||object_name||' compile;'
from dba_objects
where status='INVALID' and wner='&' and object_type in ('PACKAGE','PACKAGE BODY');
/
select owner,object_name,object_type,status from dba_objects where status='INVALID';
--求process/session的状态
select p.pid,p.spid,s.program,s.sid,s.serial#
from v$process p,v$session s where s.paddr=p.addr;
--求当前session的状态
select sn.name,ms.value
from v$mystat ms,v$statname sn
where ms.statistic#=sn.statistic# and ms.value > 0;
--求表的索引信息
select ui.table_name,ui.index_name
from user_indexes ui,user_ind_columns uic
where ui.table_name=uic.table_name and ui.index_name=uic.index_name
and ui.table_name like '&table_name%' and uic.column_name='&column_name';
--显示表的外键信息
col search_condition format a54
select table_name,constraint_name
from user_constraints
where constraint_type ='R' and constraint_name in (select constraint_name from user_cons_columns where column_name='&1');
select rpad(child.table_name,25,' ') child_tablename,
rpad(cp.column_name,17,' ') referring_column,rpad(parent.table_name,25,' ') parent_tablename,
rpad(pc.column_name,15,' ') referred_column,rpad(child.constraint_name,25,' ') constraint_name
from user_constraints child,user_constraints parent,
user_cons_columns cp,user_cons_columns pc
where child.constraint_type = 'R' and child.r_constraint_name = parent.constraint_name and
child.constraint_name = cp.constraint_name and parent.constraint_name = pc.constraint_name and
cp.position = pc.position and child.table_name ='&table_name'
order by child.owner,child.table_name,child.constraint_name,cp.position;
--显示表的分区及子分区(user_tab_subpartitions)
col table_name format a16
col partition_name format a16
col high_value format a81
select table_name,partition_name,HIGH_VALUE from user_tab_partitions where table_name='&table_name'
--使用dbms_xplan生成一个执行计划
explain plan set statement_id = '&sql_id' for &sql;
select * from table(dbms_xplan.display);
--求某个事务的重做信息(bytes)
select s.name,m.value
from v$mystat m,v$statname s
where m.statistic#=s.statistic# and s.name like '%redo size%';
--求cache中缓存超过其5%的对象
select o.owner,o.object_type,o.object_name,count(b.objd)
from v$bh b,dba_objects o
where b.objd = o.object_id
group by o.owner,o.object_type,o.object_name
having count(b.objd) > (select to_number(value)*0.05 from v$parameter where name = 'db_block_buffers');
--求谁阻塞了某个session(10g)
select sid, username, event, blocking_session,
seconds_in_wait, wait_time
from v$session where state in ('WAITING') and wait_class != 'Idle';
--求session的OS进程ID
col program format a54
select p.spid "OS Thread", b.name "Name-User", s.program
from v$process p, v$session s, v$bgprocess b
where p.addr = s.paddr and p.addr = b.paddr
UNION ALL
select p.spid "OS Thread", s.username "Name-User", s.program
from v$process p, v$session s where p.addr = s.paddr and s.username is not null;
--查会话的阻塞
col user_name format a32
select /*+ rule */ lpad(' ',decode(l.xidusn ,0,3,0))||l.oracle_username user_name, o.owner,o.object_name,s.sid,s.serial#
from v$locked_object l,dba_objects o,v$session s
where l.object_id=o.object_id and l.session_id=s.sid order by o.object_id,xidusn desc ;
col username format a15
col lock_level format a8
col owner format a18
col object_name format a32
select /*+ rule */ s.username, decode(l.type,'tm','table lock', 'tx','row lock', null) lock_level, o.owner,o.object_name,s.sid,s.serial#
from v$session s,v$lock l,dba_objects o
where l.sid = s.sid and l.id1 = o.object_id(+) and s.username is not null ;
--求等待的事件及会话信息/求会话的等待及会话信息
select se.sid,s.username,se.event,se.total_waits,se.time_waited,se.average_wait
from v$session s,v$session_event se
where s.username is not null and se.sid=s.sid and s.status='ACTIVE' and se.event not like '%SQL*Net%' order by s.username;
select s.sid,s.username,sw.event,sw.wait_time,sw.state,sw.seconds_in_wait
from v$session s,v$session_wait sw
where s.username is not null and sw.sid=s.sid and sw.event not like '%SQL*Net%' order by s.username;
--求会话等待的file_id/block_id
col event format a24
col p1text format a12
col p2text format a12
col p3text format a12
select sid,event,p1text, p1, p2text, p2, p3text, p3
from v$session_wait
where event not like '%SQL%' and event not like '%rdbms%' and event not like '%mon%' order by event;
select name,wait_time from v$latch l where exists (select 1 from (select sid,event,p1text, p1, p2text, p2, p3text, p3
from v$session_wait
where event not like '%SQL%' and event not like '%rdbms%' and event not like '%mon%'
) x where x.p1= l.latch#);
--求会话等待的对象
col owner format a18
col segment_name format a32
col segment_type format a32
select owner,segment_name,segment_type
from dba_extents
where file_id = &file_id and &block_id between block_id and block_id + blocks - 1;
--求buffer cache中的块信息
select o.OBJECT_TYPE, substr(o.OBJECT_NAME,1,10) objname , b.objd , b.status, count(b.objd)
from v$bh b, dba_objects o
where b.objd = o.data_object_id and o.owner = '&1' group by o.object_type, o.object_name,b.objd, b.status ;
--求日志文件的空间使用
select le.leseq current_log_sequence#, 100*cp.cpodr_bno/le.lesiz percentage_full
from x$kcccp cp,x$kccle le
where le.leseq =cp.cpodr_seq;
--求等待中的对象
select /*+rule */ s.sid, s.username, w.event, o.owner, o.segment_name, o.segment_type,
o.partition_name, w.seconds_in_wait seconds, w.state
from v$session_wait w, v$session s, dba_extents o
where w.event in (select name from v$event_name where parameter1 = 'file#'
and parameter2 = 'block#' and name not like 'control%')
and o.owner <> 'sys' and w.sid = s.sid and w.p1 = o.file_id and w.p2 >= o.block_id and w.p2 < o.block_id + o.blocks
--求当前事务的重做尺寸
select value
from v$mystat, v$statname
where v$mystat.statistic# = v$statname.statistic# and v$statname.name = 'redo size';
--唤醒smon去清除临时段
column pid new_value Smon
set termout off
select p.pid from sys.v_$bgprocess b,sys.v_$process p where b.name = 'SMON' and p.addr = b.paddr
/
set termout on
oradebug wakeup &Smon
undefine Smon
--求回退率
select b.value/(a.value + b.value),a.value,b.value from v$sysstat a,v$sysstat b
where a.statistic#=4 and b.statistic#=5;
--求DISK READ较多的SQL
select st.sql_text from v$sql s,v$sqltext st
where s.address=st.address and s.hashvalue=st.hash_value and s.disk_reads > 300;
--求DISK SORT严重的SQL
select sess.username, sql.sql_text, sort1.blocks
from v$session sess, v$sqlarea sql, v$sort_usage sort1
where sess.serial# = sort1.session_num
and sort1.sqladdr = sql.address
and sort1.sqlhash = sql.hash_value and sort1.blocks > 200;
--求对象的创建代码
column column_name format a36
column sql_text format a99
select dbms_metadata.get_ddl('TABLE','&1') from dual;
select dbms_metadata.get_ddl('INDEX','&1') from dual;
--求表的索引
set linesize 131
select a.index_name,a.column_name,b.status, b.index_type
from user_ind_columns a,user_indexes b
where a.index_name=b.index_name and a.table_name='&1';
求索引中行数较多的
select index_name,blevel,num_rows,CLUSTERING_FACTOR,status from user_indexes where num_rows > 10000 and blevel > 0
select table_name,index_name,blevel,num_rows,CLUSTERING_FACTOR,status from user_indexes where status <> 'VALID'
--求当前会话的SID,SERIAL#
select sid, serial# from v$session where audsid = SYS_CONTEXT('USERENV','SESSIONID');
--求表空间的未用空间
col mbytes format 9999.9999
select tablespace_name,sum(bytes)/1024/1024 mbytes from dba_free_space group by tablespace_name;
--求表中定义的触发器
select table_name,index_type,index_name,uniqueness from user_indexes where table_name='&1';
select trigger_name from user_triggers where table_name='&1';
--求未定义索引的表
select table_name from user_tables where table_name not in (select table_name from user_ind_columns);
--执行常用的过程
exec print_sql('select count(*) from tab');
exec show_space2('table_name');
--求free memory
select * from v$sgastat where name='free memory';
select a.name,sum(b.value) from v$statname a,v$sesstat b where a.statistic# = b.statistic# group by a.name;
查看一下谁在使用那个可以得回滚段,或者查看一下某个可以得用户在使用回滚段,
找出领回滚段不断增长的事务,再看看如何处理它,是否可以将它commit,再不行
就看看能否kill它,等等,查看当前正在使用的回滚段的用户信息和回滚段信息:
set linesize 121
SELECT r.name "ROLLBACK SEGMENT NAME ",l.sid "ORACLEPID",p.spid "SYSTEM PID ",s.username "ORACLE USERNAME"
FROM v$lock l, v$process p, v$rollname r, v$session s
WHERE l.sid = p.pid(+) AND s.sid=l.sid AND TRUNC(l.id1(+)/65536) = r.usn AND l.type(+) = 'TX' AND l.lmode(+) = 6 ORDER BY r.name;
--查看用户的回滚段的信息
select s.username, rn.name from v$session s, v$transaction t, v$rollstat r, v$rollname rn
where s.saddr = t.ses_addr and t.xidusn = r.usn and r.usn = rn.usn
--生成执行计划
explain plan set statement_id='a1' for &1;
--查看执行计划
select lpad(' ',2*(level-1))||operation operation,options,OBJECT_NAME,position from plan_table
start with id=0 and statement_id='a1' connect by prior id=parent_id and statement_id='a1'
执行计划
1)根据SID,从v$sql中找到相应SQL的HASH_VALUE和ADDRESS ;
SELECT a.sql_text , a.address , a.hash_value
FROM v$sql a , v$session b
where a.hash_value = b.sql_hash_value
and b.sid = &sid ;
Alan Lee(160921) 22:58:07
2)根据hash_value和address的值,从v$sql_plan中找到真实的执行计划。
set line 200;
col oper format a100;
select lpad(oper,length(oper)+level*2,' ') oper,cost
from (
select object_name||':'||operation||' '||options as oper,cost,id,parent_id
from v$sql_plan
where hash_value = &hash_value
and address = '&address'
)
start with id=0
connect by prior id = parent_id;
Alan Lee(160921) 22:58:26
这2步,就可以找出实际正在跑的SQL使用的是什么执行计划
set autotrace traceonly statistics
set autotrace traceonly explain
set autotrace traceonly on explain
--查看内存中存的使用
select decode(greatest(class,10),10,decode(class,1,'Data',2,'Sort',4,'Header',to_char(class)),'Rollback') "Class",
sum(decode(bitand(flag,1),1,0,1)) "Not Dirty",sum(decode(bitand(flag,1),1,1,0)) "Dirty",
sum(dirty_queue) "On Dirty",count(*) "Total"
from x$bh group by decode(greatest(class,10),10,decode(class,1,'Data',2,'Sort',4,'Header',to_char(class)),'Rollback');
--查看表空间状态
select tablespace_name,extent_management,segment_space_management from dba_tablespaces;
select table_name,freelists,freelist_groups from user_tables;
--查看系统请求情况
SELECT DECODE (name, 'summed dirty write queue length', value)/
DECODE (name, 'write requests', value) "Write Request Length"
FROM v$sysstat WHERE name IN ( 'summed dirty queue length', 'write requests') and value>0;