I have upgraded to 7.0p2 and am still seeing the creeping memory.
I have tried the following...
1. Added the following statement to my .clp file:
(set-node-index-hash 1)
2. Changed the jess.TokenTree#clear() method to allow for debugging:
final void clear() {
for (int i=0; i< m_hash; i++)
if (m_tokens[i] != null)
m_tokens[i].clear();
m_size = 0;
int filledCnt = 0;
for (int i=0; i< m_tokens.length; i++)
if (m_tokens[i] != null)
filledCnt++;
if (filledCnt > 0)
{
System.out.println(
"filledCnt="+filledCnt+
"; m_tokens.length="+m_tokens.length+
"; instance="+this.hashCode());
}
}
When I run my Rete execution in a loop I see the m_tokens array is
steadily increasing and the number of non-null values increasing.
The only way to prevent this is to change the Jess source code as you
suggest below. When I put in the call to Arrays.fill() then the memory
stops growing.
I am very hesitant to change the Jess source code as we use several
different usage patterns, some are transaction-oriented, some are more
knowledge-based.
I guess I don't understand the value of retaining the older tokens.
Some questions I still have:
* What is the value of the retained tokens?
* Isn't the algorithm for releasing the tokens somewhat arbitrary?
* How can I test for the upper limit on the array size you mention?
* Why does my setting for set-node-index-hash-value have little or no
effect?
I am just trying to understand the behavior better and avoid
modifications to the source code if at all possible. If you can guide
me on a way to keep the memory down within the current Jess source code
I would be grateful.
Matt
-----Original Message-----
From: Ernest Friedman-Hill [mailto:[EMAIL PROTECTED]
Sent: Tuesday, January 08, 2008 3:21 PM
To: Matt Accola
Subject: Re: JESS: TokenTree memory leak?
On Jan 8, 2008, at 4:06 PM, Matt Accola wrote:
> We should have upgraded the library long ago, it has just fallen
> lower on priorities. I am trying that now but need to do a
> regression.
>
> We are calling the Rete engine repetitively in our application and
> at the end of each evaluation we call the reset() method to return
> the engine to empty state, ready for the next call. Is there any
> way to force all memory to be reclaimed and override this memory
> retention you described?
There's no built-in way, but it would be an easy mod. In jess/
TokenTree.java, there's a method like
final void clear() {
for (int i=0; i< m_hash; i++)
if (m_tokens[i] != null)
m_tokens[i].clear();
m_size = 0;
}
You could just change it to something like
final void clear() {
java.util.Arrays.fill(m_tokens, null);
m_size = 0;
}
Note that there's a performance tradeoff here; the next run will very
likely turn around and re-allocate many of these same objects. Jess
is lazy-initializing the contents of that m_tokens array, one element
at a time; when all the m_tokens arrays of all the TokenTree objects
are non-null, that's the upper limit I mentioned. Which of the
possible array elements is populated on any one run is going to
depend entirely on the data for that run.
>
> Confidentiality Notice:
> **********************************************
> This E-mail and any attachments thereto, are intended only for use
> by the addressee(s) named herein and may contain legally privileged
> and/or confidential information. If you are not the intended
> recipient of this E-mail, you are hereby notified any
> dissemination, distribution or copying of this E-mail, and any
> attachments thereto, is strictly prohibited. If you receive this E-
> mail in error, please immediately notify me by reply E-mail or
> telephone at (218) 723-7887 and permanently delete the original and
> any copy of this E-mail, and any printout thereof.
>
---------------------------------------------------------
Ernest Friedman-Hill
Informatics & Decision Sciences Phone: (925) 294-2154
Sandia National Labs FAX: (925) 294-2234
PO Box 969, MS 9012 [EMAIL PROTECTED]
Livermore, CA 94550 http://www.jessrules.com
Confidentiality Notice:
**********************************************
This E-mail and any attachments thereto, are intended only for use by the
addressee(s) named herein and may contain legally privileged and/or
confidential information. If you are not the intended recipient of this E-mail,
you are hereby notified any dissemination, distribution or copying of this
E-mail, and any attachments thereto, is strictly prohibited. If you receive
this E-mail in error, please immediately notify me by reply E-mail or telephone
at (218) 723-7887 and permanently delete the original and any copy of this
E-mail, and any printout thereof.
--------------------------------------------------------------------
To unsubscribe, send the words 'unsubscribe jess-users [EMAIL PROTECTED]'
in the BODY of a message to [EMAIL PROTECTED], NOT to the list
(use your own address!) List problems? Notify [EMAIL PROTECTED]
--------------------------------------------------------------------
