数据库管理员日常工作中必备的sql列表 （3）

    来源：赛迪网    作者：Alice

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，再不行就看能否kill它,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 "ORACLE PID",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'

--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;

--计算data buffer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# = 40 and b.statistic# = 41 and c.statistic# = 42;

SELECT name, (1-(physical_reads/(db_block_gets+consistent_gets)))*100 H_RATIO FROM v$buffer_pool_statistics;

--查看内存使用情况

select least(max(b.value)/(1024*1024),sum(a.bytes)/(1024*1024)) shared_pool_used,

max(b.value)/(1024*1024) shared_pool_size,greatest(max(b.value)/(1024*1024),sum(a.bytes)/(1024*1024))-

(sum(a.bytes)/(1024*1024)) shared_pool_avail,((sum(a.bytes)/(1024*1024))/(max(b.value)/(1024*1024)))*100 avail_pool_pct

from v$sgastat a, v$parameter b where (a.pool='shared pool' and a.name not in ('free memory')) and b.name='shared_pool_size';

--查看用户使用内存情况

select username, sum(sharable_mem), sum(persistent_mem), sum(runtime_mem)

from sys.v_$sqlarea a, dba_users b

where a.parsing_user_id = b.user_id group by username;

--查看对象的缓存情况

select OWNER,NAMESPACE,TYPE,NAME,SHARABLE_MEM,LOADS,EXECUTIONS,LOCKS,PINS,KEPT

from v$db_object_cache where type not in ('NOT LOADED','NON-EXISTENT','VIEW','TABLE','SEQUENCE')

and executions>0 and loads>1 and kept='NO' order by owner,namespace,type,executions desc;

select type,count(*) from v$db_object_cache group by type;

--查看库缓存命中率

select namespace,gets, gethitratio*100 gethitratio,pins,pinhitratio*100 pinhitratio,RELOADS,INVALIDATIONS from v$librarycache

--查看某些用户的hash

select a.username, count(b.hash_value) total_hash,count(b.hash_value)-count(unique(b.hash_value)) same_hash,

(count(unique(b.hash_value))/count(b.hash_value))*100 u_hash_ratio

from dba_users a, v$sqlarea b where a.user_id=b.parsing_user_id group by a.username;

--查看字典命中率

select (sum(getmisses)/sum(gets)) ratio from v$rowcache;

--查看undo段的使用情况

SELECT d.segment_name,extents,optsize,shrinks,aveshrink,aveactive,d.status

FROM v$rollname n,v$rollstat s,dba_rollback_segs d

WHERE d.segment_id=n.usn(+) and d.segment_id=s.usn(+);

--无效的对象

select owner,object_type,object_name from dba_objects where status='INVALID';

select constraint_name,table_name from dba_constraints where status='INVALID';

--求出某个进程，并对它进行跟踪

select s.sid,s.serial# from v$session s,v$process p where s.paddr=p.addr and p.spid=&1;

exec dbms_system.SET_SQL_TRACE_IN_SESSION(&1,&2,true);

exec dbms_system.SET_SQL_TRACE_IN_SESSION(&1,&2,false);

--求出锁定的对象

select do.object_name,session_id,process,locked_mode

from v$locked_object lo, dba_objects do where lo.object_id=do.object_id;

--求当前session的跟踪文件

SELECT p1.value || '/' || p2.value || '_ora_' || p.spid || '.ora' filename

FROM v$process p, v$session s, v$parameter p1, v$parameter p2

WHERE p1.name = 'user_dump_dest' AND p2.name = 'instance_name'

AND p.addr = s.paddr AND s.audsid = USERENV('SESSIONID') AND p.background is null AND instr(p.program,'CJQ') = 0;

--求对象所在的文件及块号

select segment_name,header_file,header_block

from dba_segments where segment_name like '&1';

--求对象发生事务时回退段及块号

select a.segment_name,a.header_file,a.header_block

from dba_segments a,dba_rollback_segs b

where a.segment_name=b.segment_name and b.segment_id='&1'

--9i的在线重定义表

/*如果在线重定义的表没有主键需要创建主键*/

exec dbms_redefinition.can_redef_table('cybercafe','announcement');

create table anno2 as select * from announcement

exec dbms_redefinition.start_redef_table('cybercafe','announcement','anno2');

exec dbms_redefinition.sync_interim_table('cybercafe','announcement','anno2');

exec dbms_redefinition.finish_redef_table('cybercafe','announcement','anno2');

drop table anno2

exec dbms_redefinition.abort_redef_table('cybercafe','announcement','anno2');

--常用的logmnr脚本(cybercafe)

exec sys.dbms_logmnr_d.build(dictionary_filename =>'esal',dictionary_location =>'/home/oracle/logmnr');

exec sys.dbms_logmnr.add_logfile(logfilename=>'/home/oracle/oradata/esal/archive/1_24050.dbf', ptions=>sys.dbms_logmnr.new);

exec sys.dbms_logmnr.add_logfile(logfilename=>'/home/oracle/oradata/esal/archive/1_22912.dbf', ptions=>sys.dbms_logmnr.addfile);

exec sys.dbms_logmnr.add_logfile(logfilename=>'/home/oracle/oradata/esal/archive/1_22913.dbf', ptions=>sys.dbms_logmnr.addfile);

exec sys.dbms_logmnr.add_logfile(logfilename=>'/home/oracle/oradata/esal/archive/1_22914.dbf', ptions=>sys.dbms_logmnr.addfile);

exec sys.dbms_logmnr.start_logmnr(dictfilename=>'/home/oracle/logmnr/esal.ora');

create table logmnr2 as select * from v$logmnr_contents;

--与权限相关的字典

ALL_COL_PRIVS表示列上的授权，用户和PUBLIC是被授予者

ALL_COL_PRIVS_MADE表示列上的授权，用户是属主和被授予者

ALL_COL_RECD表示列上的授权，用户和PUBLIC是被授予者

ALL_TAB_PRIVS表示对象上的授权，用户是PUBLIC或被授予者或用户是属主

ALL_TAB_PRIVS_MADE表示对象上的权限，用户是属主或授予者

ALL_TAB_PRIVS_RECD表示对象上的权限,用户是PUBLIC或被授予者

DBA_COL_PRIVS数据库列上的所有授权

DBA_ROLE_PRIVS显示已授予用户或其他角色的角色

DBA_SYS_PRIVS已授予用户或角色的系统权限

DBA_TAB_PRIVS数据库对象上的所有权限

ROLE_ROLE_PRIVS显示已授予用户的角色

ROLE_SYS_PRIVS显示通过角色授予用户的系统权限

ROLE_TAB_PRIVS显示通过角色授予用户的对象权限

SESSION_PRIVS显示用户现在可利用的所有系统权限

USER_COL_PRIVS显示列上的权限，用户是属主、授予者或被授予者

USER_COL_PRIVS_MADE显示列上已授予的权限，用户是属主或授予者

USER_COL_PRIVS_RECD显示列上已授予的权限，用户是属主或被授予者

USER_ROLE_PRIVS显示已授予给用户的所有角色

USER_SYS_PRIVS显示已授予给用户的所有系统权限

USER_TAB_PRIVS显示已授予给用户的所有对象权限

USER_TAB_PRIVS_MADE显示已授予给其他用户的对象权限，用户是属主

USER_TAB_PRIVS_RECD显示已授予给其他用户的对象权限，用户是被授予者

--如何用dbms_stats分析表及模式？

exec dbms_stats.gather_schema_stats(ownname=>'&USER_NAME',estimate_percent=>dbms_stats.auto_sample_size,

method_opt => 'for all columns size auto',degree=> DBMS_STATS.DEFAULT_DEGREE);

exec dbms_stats.gather_schema_stats(ownname=>'&USER_NAME',estimate_percent=>dbms_stats.auto_sample_size,cascade=>true);

/*

FOR ALL [INDEXED | HIDDEN] COLUMNS [size_clause]

FOR COLUMNS [size clause] column|attribute [size_clause] [,column|attribute [size_clause]...],

where size_clause is defined as size_clause := SIZE {integer | REPEAT | AUTO | SKEWONLY}

integer--Number of histogram buckets. Must be in the range [1,254].

REPEAT--Collects histograms only on the columns that already have histograms.

AUTO--Oracle determines the columns to collect histograms based on data distribution and the workload of the columns.

SKEWONLY--Oracle determines the columns to collect histograms based on the data distribution of the columns

*/