[rules-users] drools expert: memory issues

[miguel machado]

hi again,

2010/4/1 Edson Tirelli <ed.tirelli at gmail.com>

>
>    Hmm, let me complement Wolfgang's comment:
>
> > After you have taken the compiled packages from the KB and checked for
> errors, the KB has done his duty the KB ****MUST**** go :-)
>

I agree! But i don't exactly know how to do so... i mean, i call this method
which creates the KB from a DRL file and then the kbase and returns the
ksession, the KB object declaration scope is just that exact method, and
once it reaches 300MB+ in memory, it just stays there... the KB object is no
longer in use (or is it?) but memory keeps high.

I've tried setting KB to "null" and then invoking the jvm garbage collector,
but to no avail. I wish there was a simple way i could just destroy a
particular object sigh


>
>    The above emphasis is mine. KnowledgeBuilder is a higher level object
> designed to encapsulate the parsing+compilation steps of resources. It is
> **not** designed to be reused and doing so might create inconsistencies. The
> memory spike you see when using the kbuilder is due to the java compiler...


I understand that, and i'll have that if i must, but the thing is it's not
just a spike, it is prolonged throughout execution, it doesn't reduce
afterwards.


> Drools itself does not do anything fancy in there other than generate some
> code (quite inexpensive memory wise) and compile it using either JDT or
> JANINO (both quite expensive memory wise, when compared to the other steps).
>
>
>    So, I strongly discourage you keeping the KB around and as mentioned by
> Wolfgang, doing so might keep unnecessary objects in memory.
>

Like i said earlier, it's not that i want to keep KB around, i just can't
remove it.


>
>    Also, just to clarify, deserializing a compiled package means the
> compiler will not be called (obviously, as everything is already compiled)
> and that is why it should save you memory.
>

Thanks for clarifying that! I've tested with a separate application to build
a compiled file and then load it in the main system and it really makes a
difference! it's gone to <100MB wow! However, this was just a
proof-of-concept, as i'm not sure how i could apply the same technique to
the main standalone application. Do i really have to create a separate
process/application just for building/compiling the rules, to make sure the
compilation-object-junk doesn't stay in memory along with the rest?

Thanks for all the feedback and input so far.
_ miguel


-- 
"To understand what is recursion you must first understand recursion"
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.jboss.org/pipermail/rules-users/attachments/20100401/7c723708/attachment.html