Reproduce the library cache lock wait event at 11 GB in Oracle

Reproduce the library cache lock wait event at 11 GB in Oracle

From the example below, we can see that re-Compilation of objects in the production database will lead to library cache lock, so we should try to avoid compiling objects during business peaks. If a package or complex dependency exists in the process, it can easily lead to library cache lock. Therefore, you should also pay attention to this issue during application development.

Session1:

SQL> select * from v $ version;
BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0-64bit Production
PL/SQL Release 11.2.0.1.0-Production
CORE 11.2.0.1.0 Production
TNS for Linux: Version 11.2.0.1.0-Production
NLSRTL Version 11.2.0.1.0-Production
 
SQL> create or replace procedure pining
Is
Begin
Null;
End;
/
SQL> create or replace procedure calling
Is
Begin
Pining;
Dbms_lock.sleep (200 );
End;
 
/
 
Session2:
 
Alter procedure pining compile;
 

Session3:
 

Drop procedure pining;
 

Session4:
 

SQL> select sid, event, wait_class, seconds_in_wait
2 from v $ session_wait w
3 where w. WAIT_CLASS <> 'idle ';
Sid event WAIT_CLASS
------------------------------------------------------------------------------------------
6 library cache lock Concurrency
132 library cache pin Concurrency
191 SQL * Net message to client Network

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