SQL：执行计划的几种方法
2016-07-23 09:56
351 查看
查看sql执行计划方法
1.set autotrace （需要执行sql)
2.explain plan for
3.dbms_xplan.display_cursor
4.dbms_xplan.display_awr
5.查看SQL语句执行计划的个数
6.sql_trace
7.10046
8.oradebug
9.删除执行计划：
---------------------------------------------------------
查看Oracle执行计划的几种方法
一、autotrace --都要执行sql
set autotrace on
select * from dual;
set autotrace traceonly --不显示输出结果
二、explain plan for
EXPLAIN PLAN FOR select * from tableA where paraA=1；
select * from table(DBMS_XPLAN.DISPLAY) ；
或者
EXPLAIN PLAN FOR select * from tableA where paraA=1；
@?/rdbms/admin/utlxpls.sql
SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_CURSOR(FORMAT=>'+ALLSTATS'));
set verify off
select s.sid,s.serial#,s.sql_id,s.username from v$session s,v$process p where s.paddr=p.addr and p.spid='&spid';
select SID,SERIAL#,SQL_ID,sql_child_number,status,last_call_et from v$session where sql_id='&sqlid';
SID SERIAL# SQL_ID SQL_CHILD_NUMBER STATUS LAST_CALL_ET
---------- ---------- -------------------------- ---------------- ---------------- ------------
200 65 14rxtm6jhddh0 0 ACTIVE 297
从内存中获取当前会话SQL语句的执行计划
set verify off
select * from table(dbms_xplan.display_cursor('&sqlid',&sql_child_number,'last'));
直接从AWR中获取SQL语句执行计划
set verify off
select * from table(dbms_xplan.display_awr('&sqlid'));
查看通过AWR的查看SQL语句执行计划的变化
set verify off
col begin_interval_time for a35
select a.instance_number,a.snap_id,a.sql_id,a.plan_hash_value,b.begin_interval_time
from dba_hist_sqlstat a,dba_hist_snapshot b
where a.snap_id=b.snap_id
and a.sql_id='&sqlid'
order by a.instance_number,b.begin_interval_time desc;
查看SQL语句执行计划的个数
select sql_id,hash_value,child_number,plan_hash_value from v$sql_plan where sql_id='&sqlid';
select * from table(dbms_xplan.display_cursor('&sqlid',&sql_child_number,'last'));
三、sql_trace
alter session set SQL_TRACE=true;
SQL> alter session set SQL_TRACE=true;
寻找路径方法如下：
方法1： alter session set tracefile_identifier=test;
方法2： select * from v$diag_info where name like 'Default%'
SQL> select * from dual;
SQL> alter session set SQL_TRACE=false;
开启跟踪:SQL> exec dbms_system.set_SQL_TRACE_in_session(127,31923,true);
关闭跟踪:SQL> exec dbms_system.set_SQL_TRACE_in_session(127,31923,false);
select spid from v$process where addr in ( select paddr from v$session where sid=127 ) ;
cd /u01/app/oracle/diag/rdbms/r5/r5/trace
ll *30180*
tkprof r5_ora_30180.trc a.txt
vi a.txt
四、10046
开启:SQL> alter session set events '10046 trace name context forever, level 8';
关闭:SQL> alter session set events '10046 trace name context off';
对其他用户进行设置：
SQL> select sid,serial#,username from v$session where username='XXX';
SID SERIAL# USERNAME
------ ---------- ------------------
127 31923 A
SQL> exec dbms_system.set_ev(127,31923,10046,8,'A');
--使用一下SQL找到当前session的跟踪文件：
SELECT d.value|| '/' ||lower(rtrim(i.instance, chr( 0 )))|| '_ora_' ||p.spid|| '.trc' trace_file_name
from
( select p.spid
from v$mystat m
,v$session s
, v$process p
where m.statistic# = 1
and s.sid = m.sid
and p.addr = s.paddr) p,
( select t.instance
from v$thread t
,v$parameter v
where v.name = 'thread'
and (v.value = 0 or t.thread# = to_number(v.value))) i,
( select value
from v$parameter
where name = 'user_dump_dest' ) d;
--其它用户的 session:
SELECT d.value|| '/' ||lower(rtrim(i.instance, chr( 0 )))|| '_ora_' ||p.spid|| '.trc'trace_file_name
from
( select p.spid
from v$session s
,v$process p
where s.sid= '27'
and s. SERIAL#= '30'
and p.addr = s.paddr) p,
( select t.instance
from v$thread t
,v$parameter v
where v.name = 'thread'
and (v.value = 0 or t.thread# = to_number(v.value))
) i,
( select value
from v$parameter
where name = 'user_dump_dest' ) d;
五、oradebug
SQL> select p.PID,p.SPID,s.SID from v$process p,v$session s where s.paddr = p.addr and s.sid = 421;
PID SPID SID
---------- ------------ ----------
28 241816 421
SQL> oradebug setospid 241816
Oracle pid: 28, Unix process pid: 241816, image: oracle@p690ca
SQL> oradebug unlimit
已处理的语句
SQL> oradebug event 10046 trace name context forever,level 12
已处理的语句
oradebug tracefile_name
/u01/app/oracle/admin/ipratest/udump/ipratest_ora_241816.trc
oradebug event 10046 trace name context off
1> oradebug有哪些可用命令？
以sysdba身份登陆数据库，通过oradebug help可以看到oradebug常用命令
sqlplus / as sysdba
oradebug help
2> 跟踪当前会话信息
oradebug setmypid --跟踪当前会话
oradebug setospid --跟踪系统进程
oradebug setorapid --跟踪ORACLE进程
oradebug unlimit --取消trace文件大小限制
oradebug tracefile_name --查看trace文件名及位置
3> 用oradebug做session级10046或10053
oradebug setmypid
oradebug unlimit
oradebug session_event 10046 trace name context forever ,level 4 --启用会话级10046
oradebug event 10046 trace name context off --关闭10046事件
oradebug tracefile_name --查看tracefile文件位置及文件名
4> 用oradebug做oracle process级10046
oradebug setorapid
oradebug unlimit
oradebug event 10046 trace name context forever ,level 4
oradebug event 10046 trace name context off
oradebug tracefile_name
5> oradebug系统hang住原因分析
如果系统HANG住，只要sys用户可以登陆，那么用oradebug做原因分析是非常有用的
oradebug setmypid
oradebug unlimit
oradebug setinst all --RAC环境
oradebug hanganalyze 3 -- 级别一般指定为3足够了
oradebug -g def dump systemstate 10 --RAC环境
oradebug tracefile_name
6> 获取某进程的状态信息
oradebug setospid 22180
oradebug dump processstate 10
oradebug tracefile_name
7> 获取进程错误信息状态
oradebug setospid 22180
oradebug dump errorstack 3
8> 追踪造成错误信息的原因，如ORA-04031
oradebug event 4031 trace name errorstack level 3
这些是常用到的一些命令，更多信息参考DAVE博客，他介绍的比较详解
http://blog.csdn.net/tianlesoftware/article/details/6525628
第一步：
EXPLAIN PLAN FOR select * from tableA where paraA=1
第二步：
select * from table(DBMS_XPLAN.DISPLAY) ；
1.
SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_CURSOR(FORMAT=>'+ALLSTATS'));
2.
select /*+ gather_plan_statistics */ count(*) from aa
3.
SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_CURSOR(FORMAT=>'+ALLSTATS'));
2．用explain plan命令
sqlplus > explain plan for select * from testdb.myuser
sqlplus > select * from table(dbms_xplan.display);
3、启用SQL_TRACE跟踪所有后台进程活动：
SQL> alter session set SQL_TRACE=true;
方法1： alter session set tracefile_identifier=test;
方法2： select * from v$diag_info where name like 'Default%'
开启跟踪:SQL> exec dbms_system.set_SQL_TRACE_in_session(127,31923,true);
关闭跟踪:SQL> exec dbms_system.set_SQL_TRACE_in_session(127,31923,false);
然后使用oracle自带的tkprof命令行工具格式化跟踪文件。
/*
select a.username ,a.sid,a.serial#,a.status,b.pid,b.spid from v$session a ,v$process b where a.paddr=b.addr
*/
SQL> select spid from v$process where addr in ( select paddr from v$session where sid=127 ) ;
SPID
------------------------
30180
[oracle@nubia ~]$ cd /u01/app/oracle/diag/rdbms/r5/r5/trace
[oracle@nubia trace]$ ll *30180*
-rw-r----- 1 oracle oinstall 1005655 03-30 16:14 r5_ora_30180.trc
-rw-r----- 1 oracle oinstall 2470 03-30 16:14 r5_ora_30180.trm
[oracle@nubia trace]$ tkprof r5_ora_30180.trc a.txt
TKPROF: Release 11.2.0.2.0 - Development on Mon Mar 30 16:35:19 2015
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
[oracle@nubia trace]$ vi a.txt
4、使用10046事件进行查询：
10046事件级别：
Lv1 - 启用标准的SQL_TRACE功能,等价于SQL_TRACE
Lv4 - Level 1 + 绑定值(bind values)
Lv8 - Level 1 + 等待事件跟踪
Lv12 - Level 1 + Level 4 + Level 8
全局设定：
OracleHome/admin/SID/pfile中指定: EVENT="10046 trace name context forever,level 12"
当前session设定：
开启:SQL> alter session set events '10046 trace name context forever, level 8';
关闭:SQL> alter session set events '10046 trace name context off';
对其他用户进行设置：
SQL> select sid,serial#,username from v$session where username='XXX';
SID SERIAL# USERNAME
------ ---------- ------------------
127 31923 A
SQL> exec dbms_system.set_ev(127,31923,10046,8,'A');
5、使用tkprof格式化跟踪文件： (根据下面SQL语句得到的文件都不存在该目录下,郁闷啊,懵懂啊...)
一般，一次跟踪可以分为以下几步：
1、界定需要跟踪的目标范围，并使用适当的命令启用所需跟踪。
2、经过一段时间后，停止跟踪。此时应该产生了一个跟踪结果文件。
3、找到跟踪文件，并对其进行格式化，然后阅读或分析。
--使用一下SQL找到当前session的跟踪文件：
SELECT d.value|| '/' ||lower(rtrim(i.instance, chr( 0 )))|| '_ora_' ||p.spid|| '.trc' trace_file_name
from
( select p.spid from v$mystat m,v$session s, v$process p
where m.statistic# = 1 and s.sid = m.sid and p.addr = s.paddr) p,
( select t.instance from v$thread t,v$parameter v
where v.name = 'thread' and (v.value = 0 or t.thread# = to_number(v.value))) i,
( select value from v$parameter where name = 'user_dump_dest' ) d;
--其它用户的 session:
SELECT d.value|| '/' ||lower(rtrim(i.instance, chr( 0 )))|| '_ora_' ||p.spid|| '.trc'trace_file_name
from
( select p.spid from v$session s, v$process p
where s.sid= '27' and s. SERIAL#= '30' and p.addr = s.paddr) p,
( select t.instance from v$thread t,v$parameter v
where v.name = 'thread' and (v.value = 0 or t.thread# = to_number(v.value))) i,
( select value from v$parameter where name = 'user_dump_dest' ) d;
--查找后使用tkprof命令,将TRACE文件格式为到D盘的explain_format.txt文件中
SQL> $tkprof d:/oracle/admin/FZLGFM/udump/fzlgfm_ora_3468.trc d:/explain_format.txt
文件内容大致如下(看不太懂....懵懂啊.....天啊....神啊.....过几时就懂了/////////////)
TKPROF: Release 9.2.0.1.0 - Production on 星期二 4月 20 13:59:20 2010
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Trace file: d:/oracle/admin/FZLGFM/udump/fzlgfm_ora_3468.trc
Sort options: default
********************************************************************************
count = number of times OCI procedure was executed
cpu = cpu time in seconds executing
elapsed = elapsed time in seconds executing
disk = number of physical reads of buffers from disk
query = number of buffers gotten for consistent read
current = number of buffers gotten in current mode (usually for update)
rows = number of rows processed by the fetch or execute call
********************************************************************************
alter session set events '10046 trace name context forever, level 8'
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 0 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 0 0.00 0.00 0 0 0 0
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 1 0.00 0.00 0 0 0 0
Misses in library cache during parse: 0
Misses in library cache during execute: 1
Optimizer goal: CHOOSE
Parsing user id: SYS
sql_profle内容：
SELECT so.signature,extractValue(value(h),'.') AS hint
FROM sys.sqlobj$data od, sys.sqlobj$ so,
table(xmlsequence(extract(xmltype(od.comp_data),'/outline_data/hint'))) h
WHERE so.name = 'SYS_SQLPROF_01436cac2c3c0000'
AND so.signature = od.signature
AND so.category = od.category
AND so.obj_type = od.obj_type
AND so.plan_id = od.plan_id
alter system flush shared_pool;
删除执行计划：
在11g中，Oracle的DBMS_SHARED_POOL包新增了PURGE功能
select count(*) from dual;
select count(*) from v$sqlarea;
select sql_id, address, hash_value, executions, loads, parse_calls, invalidations ,sql_text from v$sqlarea where sql_text like '%select count(*) from dual%';
select sql_id, address, hash_value, executions, loads, parse_calls, invalidations from v$sqlarea where lower(sql_text) like '%dual%';
alter system flush shared_pool;
select count(*) from dual;
COUNT(*)
----------
1
select sql_id, address, hash_value, executions, loads, parse_calls, invalidations ,sql_text from v$sqlarea where sql_text like '%select count(*) from dual%';
SQL_ID ADDRESS HASH_VALUE EXECUTIONS LOADS PARSE_CALLS INVALIDATIONS
------------- ---------------- ---------- ---------- ---------- ----------- -------------
4m94ckmu16f9k 00000000B6C61FC0 4094900530 1 2 1 1
SQL> select 1 from dual;
1
----------
1
SQL> select * from dual;
D
-
X
select sql_id, address, hash_value, executions, loads, parse_calls, invalidations from v$sqlarea www.2cto.com where lower(sql_text) like '%dual%';
SQL_ID ADDRESS HASH_VALUE EXECUTIONS LOADS PARSE_CALLS INVALIDATIONS
------------- ---------------- ---------- ---------- ---------- ----------- -------------
gr7s3j0cg8pr6 00000000B6A5A470 418666214 3 1 3 0
520mkxqpf15q8 00000000B6DD9610 2866845384 1 2 1 1
ak90gdq0udv37 00000000B6E3C6B0 2175200359 3 2 3 1
4m94ckmu16f9k 00000000B6C61FC0 4094900530 1 2 1 1
a5ks9fhw2v9s1 00000000B698DA88 942515969 1 2 1 1
exec dbms_shared_pool.purge('00000000B6C61FC0,4094900530', 'c')
PL/SQL procedure successfully completed.
SQL> select sql_id, address, hash_value, executions, loads, parse_calls, invalidations from v$sqlarea where lower(sql_text) like '%dual%';
SQL_ID ADDRESS HASH_VALUE EXECUTIONS LOADS PARSE_CALLS INVALIDATIONS
------------- ---------------- ---------- ---------- ---------- ----------- -------------
gr7s3j0cg8pr6 00000000B6A5A470 418666214 4 1 4 0
520mkxqpf15q8 00000000B6DD9610 2866845384 1 2 1 1
ak90gdq0udv37 00000000B6E3C6B0 2175200359 3 2 3 1
a5ks9fhw2v9s1 00000000B698DA88 942515969 1 2 1 1
过程PURGE的第一个参数为V$SQLAREA中用逗号分隔的ADDRESS列和HASH_VALUE列的值，第二个参数’c’表示PURGE的对象是CURSOR，不过实际上这里可以使用除了P（PROCEDURE/FUNCTION/PACKAGE）、T（TYPE）、R（TRIGGER）和Q（SEQUENCE）的任何值 www.2cto.com
使用这种方法，就可以精确的将一个SQL从共享池中删除，从而使得Oracle为这个SQL重新生成执行计划。这种方法只针对单个SQL语句，使得解决问题的同时不会造成任何的误伤。
不过需要注意一点，在10.2.0.4中，虽然PURGE过程已经存在，但是要使这个过程可以真正的生效，还必须设置一个EVENT：
SQL> alter system set event = '5614566 trace name context forever' scope = spfile;
System altered.
设置EVENT后需要重启，DBMS_SHARED_POOL的PURGE才可以生效。也就是说，除非提前进行过设置，否则这个PURGE的功能对于一个产品环境而言，必须在10.2.0.5以上版本才可以使用。
1.set autotrace （需要执行sql)
2.explain plan for
3.dbms_xplan.display_cursor
4.dbms_xplan.display_awr
5.查看SQL语句执行计划的个数
6.sql_trace
7.10046
8.oradebug
9.删除执行计划：
---------------------------------------------------------
查看Oracle执行计划的几种方法
一、autotrace --都要执行sql
set autotrace on
select * from dual;
set autotrace traceonly --不显示输出结果
二、explain plan for
EXPLAIN PLAN FOR select * from tableA where paraA=1；
select * from table(DBMS_XPLAN.DISPLAY) ；
或者
EXPLAIN PLAN FOR select * from tableA where paraA=1；
@?/rdbms/admin/utlxpls.sql
SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_CURSOR(FORMAT=>'+ALLSTATS'));
set verify off
select s.sid,s.serial#,s.sql_id,s.username from v$session s,v$process p where s.paddr=p.addr and p.spid='&spid';
select SID,SERIAL#,SQL_ID,sql_child_number,status,last_call_et from v$session where sql_id='&sqlid';
SID SERIAL# SQL_ID SQL_CHILD_NUMBER STATUS LAST_CALL_ET
---------- ---------- -------------------------- ---------------- ---------------- ------------
200 65 14rxtm6jhddh0 0 ACTIVE 297
从内存中获取当前会话SQL语句的执行计划
set verify off
select * from table(dbms_xplan.display_cursor('&sqlid',&sql_child_number,'last'));
直接从AWR中获取SQL语句执行计划
set verify off
select * from table(dbms_xplan.display_awr('&sqlid'));
查看通过AWR的查看SQL语句执行计划的变化
set verify off
col begin_interval_time for a35
select a.instance_number,a.snap_id,a.sql_id,a.plan_hash_value,b.begin_interval_time
from dba_hist_sqlstat a,dba_hist_snapshot b
where a.snap_id=b.snap_id
and a.sql_id='&sqlid'
order by a.instance_number,b.begin_interval_time desc;
查看SQL语句执行计划的个数
select sql_id,hash_value,child_number,plan_hash_value from v$sql_plan where sql_id='&sqlid';
select * from table(dbms_xplan.display_cursor('&sqlid',&sql_child_number,'last'));
三、sql_trace
alter session set SQL_TRACE=true;
SQL> alter session set SQL_TRACE=true;
寻找路径方法如下：
方法1： alter session set tracefile_identifier=test;
方法2： select * from v$diag_info where name like 'Default%'
SQL> select * from dual;
SQL> alter session set SQL_TRACE=false;
开启跟踪:SQL> exec dbms_system.set_SQL_TRACE_in_session(127,31923,true);
关闭跟踪:SQL> exec dbms_system.set_SQL_TRACE_in_session(127,31923,false);
select spid from v$process where addr in ( select paddr from v$session where sid=127 ) ;
cd /u01/app/oracle/diag/rdbms/r5/r5/trace
ll *30180*
tkprof r5_ora_30180.trc a.txt
vi a.txt
四、10046
开启:SQL> alter session set events '10046 trace name context forever, level 8';
关闭:SQL> alter session set events '10046 trace name context off';
对其他用户进行设置：
SQL> select sid,serial#,username from v$session where username='XXX';
SID SERIAL# USERNAME
------ ---------- ------------------
127 31923 A
SQL> exec dbms_system.set_ev(127,31923,10046,8,'A');
--使用一下SQL找到当前session的跟踪文件：
SELECT d.value|| '/' ||lower(rtrim(i.instance, chr( 0 )))|| '_ora_' ||p.spid|| '.trc' trace_file_name
from
( select p.spid
from v$mystat m
,v$session s
, v$process p
where m.statistic# = 1
and s.sid = m.sid
and p.addr = s.paddr) p,
( select t.instance
from v$thread t
,v$parameter v
where v.name = 'thread'
and (v.value = 0 or t.thread# = to_number(v.value))) i,
( select value
from v$parameter
where name = 'user_dump_dest' ) d;
--其它用户的 session:
SELECT d.value|| '/' ||lower(rtrim(i.instance, chr( 0 )))|| '_ora_' ||p.spid|| '.trc'trace_file_name
from
( select p.spid
from v$session s
,v$process p
where s.sid= '27'
and s. SERIAL#= '30'
and p.addr = s.paddr) p,
( select t.instance
from v$thread t
,v$parameter v
where v.name = 'thread'
and (v.value = 0 or t.thread# = to_number(v.value))
) i,
( select value
from v$parameter
where name = 'user_dump_dest' ) d;
五、oradebug
SQL> select p.PID,p.SPID,s.SID from v$process p,v$session s where s.paddr = p.addr and s.sid = 421;
PID SPID SID
---------- ------------ ----------
28 241816 421
SQL> oradebug setospid 241816
Oracle pid: 28, Unix process pid: 241816, image: oracle@p690ca
SQL> oradebug unlimit
已处理的语句
SQL> oradebug event 10046 trace name context forever,level 12
已处理的语句
oradebug tracefile_name
/u01/app/oracle/admin/ipratest/udump/ipratest_ora_241816.trc
oradebug event 10046 trace name context off
1> oradebug有哪些可用命令？
以sysdba身份登陆数据库，通过oradebug help可以看到oradebug常用命令
sqlplus / as sysdba
oradebug help
2> 跟踪当前会话信息
oradebug setmypid --跟踪当前会话
oradebug setospid --跟踪系统进程
oradebug setorapid --跟踪ORACLE进程
oradebug unlimit --取消trace文件大小限制
oradebug tracefile_name --查看trace文件名及位置
3> 用oradebug做session级10046或10053
oradebug setmypid
oradebug unlimit
oradebug session_event 10046 trace name context forever ,level 4 --启用会话级10046
oradebug event 10046 trace name context off --关闭10046事件
oradebug tracefile_name --查看tracefile文件位置及文件名
4> 用oradebug做oracle process级10046
oradebug setorapid
oradebug unlimit
oradebug event 10046 trace name context forever ,level 4
oradebug event 10046 trace name context off
oradebug tracefile_name
5> oradebug系统hang住原因分析
如果系统HANG住，只要sys用户可以登陆，那么用oradebug做原因分析是非常有用的
oradebug setmypid
oradebug unlimit
oradebug setinst all --RAC环境
oradebug hanganalyze 3 -- 级别一般指定为3足够了
oradebug -g def dump systemstate 10 --RAC环境
oradebug tracefile_name
6> 获取某进程的状态信息
oradebug setospid 22180
oradebug dump processstate 10
oradebug tracefile_name
7> 获取进程错误信息状态
oradebug setospid 22180
oradebug dump errorstack 3
8> 追踪造成错误信息的原因，如ORA-04031
oradebug event 4031 trace name errorstack level 3
这些是常用到的一些命令，更多信息参考DAVE博客，他介绍的比较详解
http://blog.csdn.net/tianlesoftware/article/details/6525628
第一步：
EXPLAIN PLAN FOR select * from tableA where paraA=1
第二步：
select * from table(DBMS_XPLAN.DISPLAY) ；
1.
SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_CURSOR(FORMAT=>'+ALLSTATS'));
2.
select /*+ gather_plan_statistics */ count(*) from aa
3.
SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_CURSOR(FORMAT=>'+ALLSTATS'));
2．用explain plan命令
sqlplus > explain plan for select * from testdb.myuser
sqlplus > select * from table(dbms_xplan.display);
3、启用SQL_TRACE跟踪所有后台进程活动：
SQL> alter session set SQL_TRACE=true;
方法1： alter session set tracefile_identifier=test;
方法2： select * from v$diag_info where name like 'Default%'
开启跟踪:SQL> exec dbms_system.set_SQL_TRACE_in_session(127,31923,true);
关闭跟踪:SQL> exec dbms_system.set_SQL_TRACE_in_session(127,31923,false);
然后使用oracle自带的tkprof命令行工具格式化跟踪文件。
/*
select a.username ,a.sid,a.serial#,a.status,b.pid,b.spid from v$session a ,v$process b where a.paddr=b.addr
*/
SQL> select spid from v$process where addr in ( select paddr from v$session where sid=127 ) ;
SPID
------------------------
30180
[oracle@nubia ~]$ cd /u01/app/oracle/diag/rdbms/r5/r5/trace
[oracle@nubia trace]$ ll *30180*
-rw-r----- 1 oracle oinstall 1005655 03-30 16:14 r5_ora_30180.trc
-rw-r----- 1 oracle oinstall 2470 03-30 16:14 r5_ora_30180.trm
[oracle@nubia trace]$ tkprof r5_ora_30180.trc a.txt
TKPROF: Release 11.2.0.2.0 - Development on Mon Mar 30 16:35:19 2015
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
[oracle@nubia trace]$ vi a.txt
4、使用10046事件进行查询：
10046事件级别：
Lv1 - 启用标准的SQL_TRACE功能,等价于SQL_TRACE
Lv4 - Level 1 + 绑定值(bind values)
Lv8 - Level 1 + 等待事件跟踪
Lv12 - Level 1 + Level 4 + Level 8
全局设定：
OracleHome/admin/SID/pfile中指定: EVENT="10046 trace name context forever,level 12"
当前session设定：
开启:SQL> alter session set events '10046 trace name context forever, level 8';
关闭:SQL> alter session set events '10046 trace name context off';
对其他用户进行设置：
SQL> select sid,serial#,username from v$session where username='XXX';
SID SERIAL# USERNAME
------ ---------- ------------------
127 31923 A
SQL> exec dbms_system.set_ev(127,31923,10046,8,'A');
5、使用tkprof格式化跟踪文件： (根据下面SQL语句得到的文件都不存在该目录下,郁闷啊,懵懂啊...)
一般，一次跟踪可以分为以下几步：
1、界定需要跟踪的目标范围，并使用适当的命令启用所需跟踪。
2、经过一段时间后，停止跟踪。此时应该产生了一个跟踪结果文件。
3、找到跟踪文件，并对其进行格式化，然后阅读或分析。
--使用一下SQL找到当前session的跟踪文件：
SELECT d.value|| '/' ||lower(rtrim(i.instance, chr( 0 )))|| '_ora_' ||p.spid|| '.trc' trace_file_name
from
( select p.spid from v$mystat m,v$session s, v$process p
where m.statistic# = 1 and s.sid = m.sid and p.addr = s.paddr) p,
( select t.instance from v$thread t,v$parameter v
where v.name = 'thread' and (v.value = 0 or t.thread# = to_number(v.value))) i,
( select value from v$parameter where name = 'user_dump_dest' ) d;
--其它用户的 session:
SELECT d.value|| '/' ||lower(rtrim(i.instance, chr( 0 )))|| '_ora_' ||p.spid|| '.trc'trace_file_name
from
( select p.spid from v$session s, v$process p
where s.sid= '27' and s. SERIAL#= '30' and p.addr = s.paddr) p,
( select t.instance from v$thread t,v$parameter v
where v.name = 'thread' and (v.value = 0 or t.thread# = to_number(v.value))) i,
( select value from v$parameter where name = 'user_dump_dest' ) d;
--查找后使用tkprof命令,将TRACE文件格式为到D盘的explain_format.txt文件中
SQL> $tkprof d:/oracle/admin/FZLGFM/udump/fzlgfm_ora_3468.trc d:/explain_format.txt
文件内容大致如下(看不太懂....懵懂啊.....天啊....神啊.....过几时就懂了/////////////)
TKPROF: Release 9.2.0.1.0 - Production on 星期二 4月 20 13:59:20 2010
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Trace file: d:/oracle/admin/FZLGFM/udump/fzlgfm_ora_3468.trc
Sort options: default
********************************************************************************
count = number of times OCI procedure was executed
cpu = cpu time in seconds executing
elapsed = elapsed time in seconds executing
disk = number of physical reads of buffers from disk
query = number of buffers gotten for consistent read
current = number of buffers gotten in current mode (usually for update)
rows = number of rows processed by the fetch or execute call
********************************************************************************
alter session set events '10046 trace name context forever, level 8'
call count cpu elapsed disk query current rows
------- ------ -------- ---------- ---------- ---------- ---------- ----------
Parse 0 0.00 0.00 0 0 0 0
Execute 1 0.00 0.00 0 0 0 0
Fetch 0 0.00 0.00 0 0 0 0
------- ------ -------- ---------- ---------- ---------- ---------- ----------
total 1 0.00 0.00 0 0 0 0
Misses in library cache during parse: 0
Misses in library cache during execute: 1
Optimizer goal: CHOOSE
Parsing user id: SYS
sql_profle内容：
SELECT so.signature,extractValue(value(h),'.') AS hint
FROM sys.sqlobj$data od, sys.sqlobj$ so,
table(xmlsequence(extract(xmltype(od.comp_data),'/outline_data/hint'))) h
WHERE so.name = 'SYS_SQLPROF_01436cac2c3c0000'
AND so.signature = od.signature
AND so.category = od.category
AND so.obj_type = od.obj_type
AND so.plan_id = od.plan_id
alter system flush shared_pool;
删除执行计划：
在11g中，Oracle的DBMS_SHARED_POOL包新增了PURGE功能
select count(*) from dual;
select count(*) from v$sqlarea;
select sql_id, address, hash_value, executions, loads, parse_calls, invalidations ,sql_text from v$sqlarea where sql_text like '%select count(*) from dual%';
select sql_id, address, hash_value, executions, loads, parse_calls, invalidations from v$sqlarea where lower(sql_text) like '%dual%';
alter system flush shared_pool;
select count(*) from dual;
COUNT(*)
----------
1
select sql_id, address, hash_value, executions, loads, parse_calls, invalidations ,sql_text from v$sqlarea where sql_text like '%select count(*) from dual%';
SQL_ID ADDRESS HASH_VALUE EXECUTIONS LOADS PARSE_CALLS INVALIDATIONS
------------- ---------------- ---------- ---------- ---------- ----------- -------------
4m94ckmu16f9k 00000000B6C61FC0 4094900530 1 2 1 1
SQL> select 1 from dual;
1
----------
1
SQL> select * from dual;
D
-
X
select sql_id, address, hash_value, executions, loads, parse_calls, invalidations from v$sqlarea www.2cto.com where lower(sql_text) like '%dual%';
SQL_ID ADDRESS HASH_VALUE EXECUTIONS LOADS PARSE_CALLS INVALIDATIONS
------------- ---------------- ---------- ---------- ---------- ----------- -------------
gr7s3j0cg8pr6 00000000B6A5A470 418666214 3 1 3 0
520mkxqpf15q8 00000000B6DD9610 2866845384 1 2 1 1
ak90gdq0udv37 00000000B6E3C6B0 2175200359 3 2 3 1
4m94ckmu16f9k 00000000B6C61FC0 4094900530 1 2 1 1
a5ks9fhw2v9s1 00000000B698DA88 942515969 1 2 1 1
exec dbms_shared_pool.purge('00000000B6C61FC0,4094900530', 'c')
PL/SQL procedure successfully completed.
SQL> select sql_id, address, hash_value, executions, loads, parse_calls, invalidations from v$sqlarea where lower(sql_text) like '%dual%';
SQL_ID ADDRESS HASH_VALUE EXECUTIONS LOADS PARSE_CALLS INVALIDATIONS
------------- ---------------- ---------- ---------- ---------- ----------- -------------
gr7s3j0cg8pr6 00000000B6A5A470 418666214 4 1 4 0
520mkxqpf15q8 00000000B6DD9610 2866845384 1 2 1 1
ak90gdq0udv37 00000000B6E3C6B0 2175200359 3 2 3 1
a5ks9fhw2v9s1 00000000B698DA88 942515969 1 2 1 1
过程PURGE的第一个参数为V$SQLAREA中用逗号分隔的ADDRESS列和HASH_VALUE列的值，第二个参数’c’表示PURGE的对象是CURSOR，不过实际上这里可以使用除了P（PROCEDURE/FUNCTION/PACKAGE）、T（TYPE）、R（TRIGGER）和Q（SEQUENCE）的任何值 www.2cto.com
使用这种方法，就可以精确的将一个SQL从共享池中删除，从而使得Oracle为这个SQL重新生成执行计划。这种方法只针对单个SQL语句，使得解决问题的同时不会造成任何的误伤。
不过需要注意一点，在10.2.0.4中，虽然PURGE过程已经存在，但是要使这个过程可以真正的生效，还必须设置一个EVENT：
SQL> alter system set event = '5614566 trace name context forever' scope = spfile;
System altered.
设置EVENT后需要重启，DBMS_SHARED_POOL的PURGE才可以生效。也就是说，除非提前进行过设置，否则这个PURGE的功能对于一个产品环境而言，必须在10.2.0.5以上版本才可以使用。
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