Hi all,

Thanks for your tips. Indeed I had some redundancy in my rule definitions, now i've removed them and it has reduced memory usage a little bit. Any other suggestions are welcome :)

thanks again.
_ miguel



2010/3/31 Wolfgang Laun <wolfgang.laun@gmail.com>
I can only offer a few hints:

Factor out all code that can be done in one of the called methods, e.g., in
  resetSource( ..., Arrays.asList($value1));
Here, the Arrays.asList() should be done in resetSource().

Avoid multiple bindings. If you call
  resetSource( $source,....)
or
  checkMayReset( $source,...)
the additional parameters $object and $CI can be retrieved within resetSource().

The funny String literals are the one thing that are strikingly different from what you usually see in rules. String literals cost for each occurrence unless you intern strings using javal.lang.String.intern(). (I haven't tried whether Drools would accept that instead.) But calculating the raw cost as (46 chars*2 bytes/char+20 bytes)*10 times * 700 rule triples  only accounts for 0.8MB, so this alone isn't the culprit.

-W


2010/3/31 Miguel Machado <mls.machado@gmail.com>

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@gmail.com> wrote:
hi again,

On 30 Mar 2010, at 18:32, Edson Tirelli <ed.tirelli@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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