From: thomas at tada.se (Thomas Hallgren)
Date: Fri, 24 Feb 2006 21:40:56 +0100
Subject: [Pljava-dev] PL/Java functions and JDBC
In-Reply-To: <44D9FC40FD695B4E85F1C59965C27E0FAA4D79@man3>
References: <44D9FC40FD695B4E85F1C59965C27E0FAA4D79@man3>
Message-ID: <43FF6F58.9040300@tada.se>

Tim Clarke wrote:
> Thomas/Patrick
> May I jump in with a question on that point? If each connection uses its
> own JVM then
> 1) Have you any idea what the approximate memory overhead is?
>   
I've measured between 20-40MB virtual memory and 6-13MB real memory per 
session using a standard Sun JVM with no special tuning. It might become 
more of course. It all depends on what you are doing.
> 2) How do we force the JVM to unload when a new JAR is released? I am
> having fun with that at the moment - I am dropping the connection
> entirely which is a bit cumbersome. This is going to give me a problem
> when I go live shortly.
>
>   
There's no way to do that at present. It wouldn't be too hard to write a 
C function that does it though, but I've had problems reloading the JVM 
after that. I'm not sure JNI is designed to handle multiple load/unload 
in a good way, nor am I sure that a JVM unload will free up a 
significant amount of memory.

Are you using a connection pool at present?

Regards,
Thomas Hallgren