Oracle單實例情況下的library cache pin的問題模擬與問題分析
Oracle單實例情況下的library cache pin的問題模擬與問題分析
參考自：
WAITEVENT: "library cache pin" Reference Note (文檔 ID 34579.1)
How to Find the Blocker of the ‘library cache pin‘ in a RAC environment? (文檔 ID 780514.1)
本機環境：Oracle 10.2.0.5 x86-64bit for RHEL5.8 x86-64bit
第一個session：
[[email protected] ~]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.5.0 - Production on Fri Jun 12 17:27:28 2015
Copyright (c) 1982, 2010, Oracle. All Rights Reserved.
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 281018368 bytes
Fixed Size 2095672 bytes
Variable Size 96470472 bytes
Database Buffers 176160768 bytes
Redo Buffers 6291456 bytes
Database mounted.
Database opened.
SQL> create user lc0019999 identified by aaaaaa;
User created.
SQL> grant dba to lc0019999;
Grant succeeded.
SQL> create user lc0029999 identified by aaaaaa;
User created.
SQL> grant dba to lc0029999;
Grant succeeded.
SQL> create user lc0039999 identified by aaaaaa;
User created.
SQL> grant dba to lc0039999;
Grant succeeded.
SQL> conn lc0019999/aaaaaa
Connected.
SQL> show user
USER is "LC0019999"
SQL> select * from v$mystat where rownum<2;
SID STATISTIC# VALUE
---------- ---------- ----------
159 0 1
SQL> Create or replace procedure dummy is
2 begin
3 null;
4 end;
5 /
Procedure created.
SQL> Begin
2 Dummy;
3 Dbms_lock.sleep(1000);
4 End;
5 /
------------>一直sleep著
以lc0029999登陸新開的一個session
[[email protected] ~]$ sqlplus lc0029999/aaaaaa
SQL*Plus: Release 10.2.0.5.0 - Production on Fri Jun 12 17:34:04 2015
Copyright (c) 1982, 2010, Oracle. All Rights Reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> select * from v$mystat where rownum<2;
SID STATISTIC# VALUE
---------- ---------- ----------
158 0 1
SQL>
SQL> alter procedure lc0019999.dummy compile;
------------>一直hang著
以sys用戶新開一個session
[[email protected] ~]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.5.0 - Production on Fri Jun 12 17:31:33 2015
Copyright (c) 1982, 2010, Oracle. All Rights Reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.5.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> set line 200
SQL> select sid, serial#,event from v$session where event like ‘%library cache pin%‘;
SID SERIAL# EVENT
---------- ---------- ----------------------------------------------------------------
158 28 library cache pin
SQL> select sid, serial#,p1raw,event from v$session where event like ‘%library cache pin%‘;
SID SERIAL# P1RAW EVENT
---------- ---------- ---------------- --------------------------------------------------
158 28 000000006BFF19B0 library cache pin
SQL> col owner for a30
SQL> col object for a30
SQL> SELECT kglnaown "Owner", kglnaobj "Object"
2 FROM x$kglob
3 WHERE kglhdadr=‘000000006BFF19B0‘---->上面查出的P1RAW值。
4 ; ---->該語句是查詢出這個等待事件發生在哪個object上。
Owner Object
------------------------------ ------------------------------
LC0019999 DUMMY
SQL>
SQL> SELECT s.sid, kglpnmod "Mode", kglpnreq "Req"
2 FROM x$kglpn p, v$session s
3 WHERE p.kglpnuse=s.saddr
4 AND kglpnhdl=‘000000006BFF19B0‘;---->該語句是查詢出這個等待事件的等待者sid（REQ>0）和持有者sid（Mode>0）
SID Mode Req
---------- ---------- ----------
158 0 3
159 2 0
SQL>
---補充：例如以下文字來源於：
<blockquote><strong><code>Mode</code></strong><span> </span>is the mode in which the pin is wanted. This is a number thus:<ul><li>2 - Share mode</li><li>3 - Exclusive mode</li></ul></blockquote>
例如以下摘自：WAITEVENT: "library cache pin" Reference Note (文檔 ID 34579.1) An X request (3) will be blocked by any pins held S mode (2) on the object. An S request (2) will be blocked by any X mode (3) pin held, or may queue behind some other X request.
Oracle單實例情況下的library cache pin的問題模擬與問題分析