Miguel,
First we need to understand where is this memory spent. Drools
externalizes the actual rule compilation to a java compiler (JDT or Janino)
and I would not be surprised if compiling 2100 rules would consume more than
300Mb **during compilation**. I don't think that after compiling, the
application will continue to use that amount of memory just because of
rules, although if you have many facts being inserted into your session, it
obviously will drive consumption up.
So, some questions:
1. Do you use one KnowledgeBuilder to compile all your rule files or do you
use one KnowledgeBuilder per file?
2. How much memory is your application using during this step, where you add
resources to your knowledgeBuilder(s)?
3. After compiling your knowledge packages, did you tried to force a GC to
check how much memory it continues to use?
4. Are you adding all rules to the same KnowledgeBase or using one kbase per
set of rules? How much memory are you consuming in this step?
5. Did you tried compiling it once, generating the kbase and serializing it
to a file, and then, instead of recompiling everything, just deserialize the
file into memory and using it? How much memory it consumes when you
deserialize from a file?
Knowing the answer to the above questions will help to determine if you
have a problem and how to work around it or fix it.
Edson
2010/3/31 Miguel Machado <mls.machado(a)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(a)gmail.com> wrote:
hi again,
On 30 Mar 2010, at 18:32, Edson Tirelli <ed.tirelli(a)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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