[rules-users] drools expert: memory issues

[Miguel Machado]

Hi, thanks for answering so quickly.

My ±2100 rules are grouped in 700 groups of 3 drools rules each, which are related to the same type of event i want to generate, like the following:


rule "event1 reset" no-loop salience 9 activation-group "event1_group" lock-on-active agenda-group "a3ce4a97-13d8-4bec-a9ab-5625fcd0f105"
	when
		$source : SourceBO( 
			ciUUID == "3938adc4-246d-43f3-b606-da4c3f09d49b",
			$object : object, 
			$CI : ciUUID, 
			$sourceUUID : sourceUUID)
		$value1 : SourceValueBO ( valueName == "VALUE1", numericValue < 90 )
		eval (checkMayReset($source, "fb95632f-fac9-4359-9d7c-dc38d3e48e20", $CI, $object))
	then
		modify ($value1) { setConditionValue(90) };
		resetSource($source, "fb95632f-fac9-4359-9d7c-dc38d3e48e20", $CI, $object, "event_version", "event_text", Arrays.asList($value1));
end

rule "event1 fire" no-loop salience 6 activation-group "event1_group" lock-on-active agenda-group "a3ce4a97-13d8-4bec-a9ab-5625fcd0f105"
	when
		$source : SourceBO( 
			ciUUID == "3938adc4-246d-43f3-b606-da4c3f09d49b",
			$object : object, 
			$CI : ciUUID, 
			$sourceUUID : sourceUUID )
		$value1: SourceValueBO ( valueName == "VALUE1", numericValue > 90 )
	then
		modify ($value1) { setConditionValue(90) };
		FireCondition $start = new FireCondition("repeat", 0, "duration", "0s");
		addToActivationQueue($source, "fb95632f-fac9-4359-9d7c-dc38d3e48e20", $CI, $object, $start, null, "event_version", "event_text", Arrays.asList($value1));
		retract($source);
end

rule "event1 clear" no-loop salience 5 activation-group "event1_group" lock-on-active agenda-group "a3ce4a97-13d8-4bec-a9ab-5625fcd0f105"
	when
		$source : SourceBO(
			ciUUID == "3938adc4-246d-43f3-b606-da4c3f09d49b",
			$object : object, 
			$CI : ciUUID, 
			$sourceUUID : sourceUUID) 
	then
		clearActivationQueue($source, "fb95632f-fac9-4359-9d7c-dc38d3e48e20", $CI, $object);
end

So, i'l try to explain briefly:
* The reset rule evaluates 2 patterns and one condition in a static method available via "import function". As a consequence, it modifies the SourceValueBO object and call's the reset function which is another static method.
* The fire rule is very similar to the reset rule, the difference being that the value threshold is different (usually the opposite)
* The clear rule is like an "else" to the two above. I want it to fire in case it didn't fall for either one of reset and fire rules.

The activation group assures that only one of these rules is fired each time i call session.fireAllRules(). And the agenda-group allows me to stack some rules above others, according to the type of facts i insert into memory.
Everything seems in place and it works as intended, the thing is i might be dealing with *lots* of events (event1, event2, etc...) and lots of different UUID's which results in a very large DRL file. For instance, if i have 700 events (event1, event ...event700), i get 2100 drools rules (event1 reset, event1 fire, event1 clear ... event700 reset, event700 fire, event700 clear) and over 300MB in consumed memory.

Perhaps if i took another approach? or some performance tunning, i don't know. Where can i improve this memory hogging?
_ miguel




On 31 Mar 2010, at 06:53, Wolfgang Laun wrote:

> The figures (+300MB) you quote are frightening, and it would be *very*
> interesting to learn what sort of rules causes this excessive amount
> of heap usage. Could you post typical patterns - if they are
> generated, there ought to be - and guestimates w.r,t, their relative
> frequencies?
> 
> -W
> 
> 
> On 3/30/10, miguel machado <mls.machado at gmail.com> wrote:
>> hi again,
>> 
>> On 30 Mar 2010, at 18:32, Edson Tirelli <ed.tirelli at gmail.com> wrote:
>> 
>>   I am not sure I understand what you are doing when you say:
>> 
>>> Every X seconds I collect the available facts and call fireAllRules() +
>> dispose(), **always within the same session**.
>> (emphasis is mine)
>> 
>> i meant that i keep using the same object, i just create one stateful
>> session throughout the program execution.
>> 
>>   Compilation indeed uses more memory, but you can compile once and reuse
>> the kbase.
>> 
>> 
>> exactly, i'm doing that, but it's a +700 rule file and its taking too much
>> memory. Is there anything i can do to push it down a little bit? i wouldn't
>> mind slowing it down to reduce memory footprint.
>> 
>> Also, if you are calling dispose, I guess you are running stateful sessions.
>> Maybe you can give us a more detailed description of your
>> session/data/application lifecycle?
>> 
>> Sure, i'll try. So i have this thread which initializes by reading the rule
>> base from a drl file. It then creates a stateful session from it and enters
>> a lifecycle in which it goes to sleep and only when some other thread wakes
>> it up, it collects and inserts some facts (usually 2,3 or 4..) into the
>> session and fire all rules. It's basically this. What i'm very concerned
>> about is the amount of RAM memory the whole program is consuming. I must
>> find a way to reduce some of it, because the rule file is being prepared by
>> an external program and i have no control over the number of rules i might
>> get. If i test it with a little over 700 rules, it reaches +300Mb which is a
>> lot.
>> 
>> Maybe the rules are too complex? Shall i try to make them simpler (how)?
>> what are the big memory hogs when it comes to loading a DRL file to the
>> knowledge base? From what i've been testing, it doesn't even matter which
>> rules you will actually need, it just loads the entire DRL file with no
>> respect to the future activations, am i right? Is there any other aspect i
>> should take in mind or maybe other approach?
>> 
>> _ miguel
>> 
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