Hello Peter, glad to meet you again after http://2012.pgconf.eu !
On ÎεÏ
19 Îοε 2012 16:26:56 you wrote:
> On 19 November 2012 08:02, Thomas Hill <Thomas.K.Hill@t-online.de> wrote:
> > was wondering if there is anyone wanted to share some experiences gained and
> > some knowledge on pl/Java. Have looked into it for a couple of days now and
> > am getting the impression it is not something ready to use in production
> > environment. Also have trouble sending to the developer mailing list (the
> > last email on the mail archive of that list is almost three weeks old) which
> > raises questions on how active this project is.
>
> I'd caution you against using pl/java in production. I came up against
> a problem with it that I could not find a satisfactory solution for.
>
> Essentially, each Postgres backend (connection process) must start its
> own JVM, and does so using the JNI. If native memory runs out (I
> realise that this may not actually be due to malloc() returning NULL,
> but the effect is about the same), this failure is handled rather
> poorly. It results in an OutOfMemoryError due to "native memory
> exhaustion".
This is the situation in J2EE app servers as well, once OutOfMemoryError is thrown
there is not much the admin can do besides killing/restarting the app server.
> This results in a segfault of the Postgres backend,
> originating from within libjvm.so. There is a workaround - which is to
> set the maximum JVM heap size to a sufficiently low value -
Wouldn't that just make the problem manifest itself earlier?
> but in
> general the need to do so left me with a very low opinion of pl/java
> as a project.
>
>
However, in most cases this error denotes a system (jvm itself) memory leak,
an insufficient garbage collector operation or a poorly designed application.
In the java 7, i heard good stories about the new G1 garbage collector.
We have never tried pl/java, despite being a postgresql/java house, and this is definitely
something we are looking forward to explore, but i agree with Thomas that the traffic on the list
is low which points to what Peter is suggesting about being scared to use this in production environments.
That would be very cool if it was much more active and stable.
-
Achilleas Mantzios
IT DEV
IT DEPT
Dynacom Tankers Mgmt