Thanks Wolfgang.
Should I conclude therefore that high memory usage is unavoidable due to the number of
facts that must be processed? I was hoping that there might be a clever way of writing the
rules so that the rules engine can minimise the network it generates - even if it takes a
little longer to execute.
All of the facts are read from a database and thus loaded into working memory. My fallback
position is to not load all these objects into working memory but instead embed into a
rule, a service call that queries the db for all inconsistencies (effectively using SQL
instead of a drools rule). However, since I will have other rules that operate on these
objects in working memory, I was hoping to use these facts for all rules.
/Ryan.
-----Original Message-----
From: rules-users-bounces(a)lists.jboss.org [mailto:rules-users-bounces@lists.jboss.org] On
Behalf Of Wolfgang Laun
Sent: 27 April 2010 14:59
To: Rules Users List
Subject: Re: [rules-users] How to make this rule more memory efficient?
If there are n Cell facts,
$cell1 : Cell()
$cell2 : Cell()
needs to create n*n pairs in the network before any reduction may set in.
Using
$cell2 : Cell(this != $cell1)
reduces this by n, so we're still quadratic. Something like
$cell1 : Cell( $id1 : id )
$cell2 : Cell( id > $id1 )
reduces it to n*(n-1)/2 which is less than 50% of the original, but still quadratic.
-W
2010/4/26 Swindells, Thomas <TSwindells(a)nds.com>:
You should probably restrict it so that
$cell2 : Cell(this != $cell1)
Thomas
From: rules-users-bounces(a)lists.jboss.org
[mailto:rules-users-bounces@lists.jboss.org] On Behalf Of Ryan
Fitzgerald
Sent: 26 April 2010 15:34
To: rules-users(a)lists.jboss.org
Subject: [rules-users] How to make this rule more memory efficient?
Hi,
Can anyone advise me on how to make a drools rule more memory efficient?
Here is the problem:
I have a Cell and a ProxyCell object classes.
The ProxyCell represents the Cell when their internal ID's match.
Each Cell and ProxyCell however has a unique name (not same as ID).
A Cell can reference (by name) a ProxyCell (as long as the ProxyCell
does not represent that actual Cell - which would effectively be a
self-reference and is not allowed).
What I want to do is find out where I have a reference from any
instance of Cell - cell1 - to any instance of ProxyCell - proxycell2 -
but am missing a reference from cell2 to proxycell1 where proxycell2
is a representation of
cell2 and proxycell1 is a representation of cell1.
Here is the rule I have written for it:
rule "Check consistent references"
when
$cell1 : Cell()
$cell2 : Cell()
$proxycell1 : ProxyCell ( id = $cell1.id, $cell2.references
contains this.name )
$proxycell2 : ProxyCell ( id = $cell2.id, $cell1.references
not contains this.name )
then
//report an error.....
end
I have 10,000 instances of Cell and 10,000 instances of ProxyCell in
working memory. For each instance of Cell, it can have references to
60 different ProxyCell instances. Loading the Cell and ProxyCell
instances into working memory is not a problem. However, when I try to
run this rule above, the memory quickly goes above 1GB and I eventually get an out of
memory error.
I was wondering if there is a better way to structure or write this
rule so that it doesn't use so much memory.
Thanks,
Ryan.
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