RE: Re: Memory Leak / Prepared Statement

John,

Please pick the driver up from http://jdbc.fastcrypt.com

This has been built from the most recent cvs

Dave

-----Original Message-----
From: pgsql-jdbc-owner@postgresql.org
[mailto:pgsql-jdbc-owner@postgresql.org] On Behalf Of John Cook
Sent: August 3, 2001 3:47 PM
To: Barry Lind
Cc: pgsql-jdbc@postgresql.org
Subject: [JDBC] Re: Memory Leak / Prepared Statement


Barry,

I got OptimizeIt configured, and it looks like it is
jdbc2/PreparedStatement which is not being garbage collected.  All of my
PreparedStatement s stay visible in Optimize it and the number of
instances never decreases.  What other information can I provide to help
determine if this is a memory leak or another problem?  I am using
Postgresql 7.1.2 and the driver that accompanied it.

Thanks.

John

Barry Lind wrote:

> My guess is that this is unlikely to be the result of the ThreadLocal
> issues and also I doubt 1.4 will have any effect.  This sounds like a
> memory leak which could be in the driver or in your application code.

> I also doubt that the use of LIKE is the problem as the JDBC code
> doesn't parse the SQL so it doesn't know if you are using LIKE or not.
>
> To fix this we would either need a reproducable test case that you
> could submit such that we could reproduce the problem and fix it, or
> you could use a java memory profiler to track down what objects are
> being allocated and not released.  I personally like OptimizeIt as it
> has helped me solve quite a few memory leak problems with java code.
>
> thanks,
> --Barry
>
> John Cook wrote:
>
> > Hi,
> >
> > I noticed several postings a month ago regarding a memory leak
> > brought about by the use of Thread.Local in
> > jdbc2/PreparedStatement.java.  I have what seems like a similar
> > problem, but I am not sure.  I have applied the patch, but I still
> > have my problem (mine is not really associated with DateFormat
> > usage.)
> >
> > I am running Enhydra Application Server 3.1 on top of Postgres and I

> > have been running an application that tries to match text strings to

> > items in my database.  It has been running fine for months until I
> > recently made a modification that uses a lot of "LIKE" statements
> > (i.e. anywhere from 2-200 at a time.)  Performance is fine, but
> > memory starts getting eaten up and I eventually hits an
> > OutOfMemoryError.  The bigger the prepared statement (i.e. the more
> > LIKEs) the more memory is eaten and the faster I run out of memory.

> > Oddly enough, before I added the LIKE statements, I was running fine

> > and, although I used a lot of prepared statements (the app server
> > did), memory was not being eaten like this.
> >
> > Has anyone had a similar experience and is it related to the
> > Thread.Local problem?  Does anyone know if this is addressed in the
> > 1.4.0 beta JDK or is it scheduled to be addressed in an upcoming
> > Postgresql release?
> >
> > Any help would be greatly appreciated.
> >
> > Thanks in advance.
> >
> > John Cook
> >
> >
> >
> >
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