Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> c.d.o.server -> Re: java_pool_size

Re: java_pool_size

From: <kuassi.mensah_at_gmail.com>
Date: 29 Dec 2006 12:00:28 -0800
Message-ID: <1167422427.915252.150000@79g2000cws.googlegroups.com>


To add to this (assuming this is about Java in the database): 1) the java_pool_size is also used by the class loader for bytecodes and other read-only class metadata when a class, not actually in SGA, needs to
be loaded.
2) the shared_pool_area is also consumed during Java initialization in the database, loadjava, Java source compilation, and Call Spec processing
3) consider setting JAVA_SOFT_SESSIONSPACE_LIMIT; it specifies (in bytes) a soft limit on Java memory usage in a session. When a user's session exceeds this size, Oracle generates a warning that goes into the trace files.
4)also JAVA_MAX_SESSIONSPACE_SIZE; it specifies (in bytes) the maximum amount of session space made available to a Java program executing in the server. When a user session attempts to exceed this limit, the session is killed, with an out-of-memory message.

There are many other Java memory areas, all described in chapter 2 of my book.
http://db360.blogspot.com/2006/08/oracle-database-programming-using-java_01.html

Kuassi

Vladimir M. Zakharychev wrote:
> aman.oracle.dba wrote:
> > hi all,
> >
> > Like for db_cache_size, we have db cache advisor and hit ratio. Do we
> > have any thing to java_pool_size.
> > Please tell me how to decide what is the good java_pool_size for the
> > database, because most of the application are on java in my new org.
>
> Do you mean that most of the application is server-side Java, or is it
> client-side Java? If the latter, then java_pool_size is irrelevant.
> Otherwise you will need to estimate the size of the Java pool by using
> your knowledge of the application footprint. 50-70mb for large
> applications is a good starting point in many cases. Java pool is only
> used for shared Java stuff, like class methods and static variables;
> regardless the number of sessions memory from the pool is not consumed
> unless new classes are loaded. If the application will hit ORA-4031
> errors, you will need to increase the pool size until they disappear
> (you can't do it dynamically, so if you can't restart the instance all
> too often then start with larger pool and monitor its usage in
> V$SGASTAT.)
>
> Hth,
> Vladimir M. Zakharychev
> N-Networks, makers of Dynamic PSP(tm)
> http://www.dynamicpsp.com
Received on Fri Dec 29 2006 - 14:00:28 CST

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US