Dejia,

Just to explain what we are talking about: antlr is the parser generator
used by JBoss Rules. So, it generates the code to parse the DRL files.
One part of the parser is a DFA that tries to predict which lexer rule
should be used by the lexer. What you see in the stack trace, is not the
same class loaded hundreds of times, but it is each of the DFA and lexer
inner classes.
There is not an easy way to "control" what antlr does when generating
the DFA and it can indeed use huge amounts of memory as it now has a
variable lookahed (LL(*)). We re-wrote some lexer rules for the new
version to workaround and reduce DFA size and memory requirements, but
it is not a simple thing to do.

Ok, this is just a highlevel overview.
In your specific case, my recomendation is that we work together toward
a possible solution that may or may not require the release of a new
version. This is because simply upgrading the antlr version may not
solve the issue. It may require some grammar rule rewriting or it may
require reconfiguration of your deploy environment.

So, to start with, can you provide:

* your full stacktrace for the out of memory error?

* your hardware and software environment, specially your memory settings
for the jvm (in websphere it is called server if I remember correctly)
where you are deploying the application?

* information about the rulebase you are using? (number of rules, size
of the rule files, samples of rules that may be offending memory the most)

I'm asking this because we have other cases of rulebases successfully
deployed to WebSphere environment without memory problems, so we need to
check if rulebase size is the only difference between your environment
and other environments or if there is also issues regarding type of
rules you are writing that are particularly stressing the lexer.

[]s
Edson


Dejia Wang wrote:

> Thanks Mark. However, with the OOM issue in JBoss Rules 3.0.5, we
> cannot really use it in enterprise environment. It would be good if we
> can get 3.0.6 out sooner.
>
> BTW, have your guys check in the fix? Is there anything we can help to
> get 3.0.6 out sooner?
>
> Thanks- Dejia
>
> ------------------------------------------------------------------------
>
> *From:* Mark Proctor [mailto:mproctor@codehaus.org]
> *Sent:* Monday, January 15, 2007 6:33 PM
> *To:* Rules Users List
> *Subject:* Re: [rules-users] Out of Memory Issue of JBoss
> Enginedeployed onIBMWAS 6.0.2.7
>
> Antlr 2.7.7 is just for the StringTemplate stuff, we are actually
> using Antlr 3. You could attempt to regenerate the grammar again with
> latest versions of antlrworks and antlr, although I'm not sure if it
> works without updates to the drl. Not sure when 3.0.6 will be out,
> probably not for a few weeks.
>
> Mark
> Dejia Wang wrote:
>
> BTW, I noticed that current stable version of antlr is 2.7.7 (released
> November 1, 2006). Rule 3.0.5 has 2.7.6.
>
> Edson, will antlr 2.7.7 work?
>
> Thanks- Dejia
>
> ------------------------------------------------------------------------
>
> *From:* Dejia Wang
> *Sent:* Monday, January 15, 2007 5:40 PM
> *To:* 'Rules Users List'
> *Subject:* RE: [rules-users] Out of Memory Issue of JBoss Engine
> deployed onIBMWAS 6.0.2.7
>
> This is good news. Thanks very much, Mark and Edson! BTW, when will
> 3.0.6 release be out?
>
> - Dejia
>
> ------------------------------------------------------------------------
>
> *From:* Mark Proctor [mailto:mproctor@codehaus.org]
> *Sent:* Monday, January 15, 2007 4:33 PM
> *To:* Rules Users List
> *Subject:* Re: [rules-users] Out of Memory Issue of JBoss Engine
> deployed onIBMWAS 6.0.2.7
>
> I believe this was a bug in antlr that is now fixed. I'll see if we
> can get a 3.0.6 release done some time updated to the latest antlr.
> Edson knows more about this, as it was a bug he investigated.
>
> Mark
> Dejia Wang wrote:
>
> BTW, I am using the JBoss Rules 3.0.5.
>
> ------------------------------------------------------------------------
>
> *From:* Dejia Wang
> *Sent:* Monday, January 15, 2007 3:56 PM
> *To:* rules-users@lists.jboss.org <mailto:rules-users@lists.jboss.org>
> *Subject:* [rules-users] Out of Memory Issue of JBoss Engine deployed
> on IBMWAS 6.0.2.7
> *Importance:* High
>
> Hi All,
>
> I ran into OOM (Out of Memory) issue of JBoss Rule Engine deployed on
> IBM WAS 6.0.2.7. Below is the log
>
> …
>
> [Loaded org.antlr.runtime.DFA from
> file:/D:/WebSphere/AppServer/profiles/AppSrv01/installedApps/xxxNode02Cell/xxx.ear/lib/antlr-3.0ea8.jar
> <file:///D:%5CWebSphere%5CAppServer%5Cprofiles%5CAppSrv01%5CinstalledApps%5CxxxNode02Cell%5Cxxx.ear%5Clib%5Cantlr-3.0ea8.jar>]
>
> [Loading superclass and interfaces of org/antlr/runtime/DFA]
>
> [Preparing org/antlr/runtime/DFA]
>
> [Loaded org.antlr.runtime.DFA$State from
> file:/D:/WebSphere/AppServer/profiles/AppSrv01/installedApps/xxxNode02Cell/xxxApplications.ear/lib/antlr-3.0ea8.jar
> <file:///D:%5CWebSphere%5CAppServer%5Cprofiles%5CAppSrv01%5CinstalledApps%5CxxxNode02Cell%5CxxxApplications.ear%5Clib%5Cantlr-3.0ea8.jar>]
>
> [Loading superclass and interfaces of org/antlr/runtime/DFA$State]
>
> [Loaded org.drools.lang.RuleParserLexer$1 from
> file:/D:/WebSphere/AppServer/profiles/AppSrv01/installedApps/xxxNode02Cell/xxxApplications.ear/lib/drools-compiler-3.0.jar
> <file:///D:%5CWebSphere%5CAppServer%5Cprofiles%5CAppSrv01%5CinstalledApps%5CxxxNode02Cell%5CxxxApplications.ear%5Clib%5Cdrools-compiler-3.0.jar>]
>
> [Loading superclass and interfaces of org/drools/lang/RuleParserLexer$1]
>
> [Loaded org.drools.lang.RuleParserLexer$2 from
> file:/D:/WebSphere/AppServer/profiles/AppSrv01/installedApps/xxxNode02Cell/
> <file:///D:%5CWebSphere%5CAppServer%5Cprofiles%5CAppSrv01%5CinstalledApps%5CxxxNode02Cell%5C>
> xxxApplications.ear/lib/drools-compiler-3.0.jar]
>
> [Loading superclass and interfaces of org/drools/lang/RuleParserLexer$2]
>
> [Loaded org.drools.lang.RuleParserLexer$3 from
> file:/D:/WebSphere/AppServer/profiles/AppSrv01/installedApps/xxxNode02Cell/
> <file:///D:%5CWebSphere%5CAppServer%5Cprofiles%5CAppSrv01%5CinstalledApps%5CxxxNode02Cell%5C>
> xxxApplications.ear/lib/drools-compiler-3.0.jar]
>
> [Loading superclass and interfaces of org/drools/lang/RuleParserLexer$3]
>
> [Loaded org.drools.lang.RuleParserLexer$4 from
> file:/D:/WebSphere/AppServer/profiles/AppSrv01/installedApps/xxxNode02Cell/
> <file:///D:%5CWebSphere%5CAppServer%5Cprofiles%5CAppSrv01%5CinstalledApps%5CxxxNode02Cell%5C>
> xxxApplications.ear/lib/drools-compiler-3.0.jar]
>
> [Loading superclass and interfaces of org/drools/lang/RuleParserLexer$4]
>
> ….
>
> [Loaded org.drools.lang.RuleParserLexer$228 from
> file:/D:/WebSphere/AppServer/profiles/AppSrv01/installedApps/xxxNode02Cell/xxxApplications.ear/lib/drools-compiler-3.0.jar
> <file:///D:%5CWebSphere%5CAppServer%5Cprofiles%5CAppSrv01%5CinstalledApps%5CxxxNode02Cell%5CxxxApplications.ear%5Clib%5Cdrools-compiler-3.0.jar>]
>
> [Loading superclass and interfaces of org/drools/lang/RuleParserLexer$228]
>
> …
>
> It looks like it loaded the same class hundreds of times until it
> exhausts the memory.
>
> Any idea why this happens and how to fix this?
>
> Thanks- Dejia
>
>
>
>
>
>
>
>
>
>
>
>
>
>------------------------------------------------------------------------
>
>
>
>
>
>
>
>
>
>
>
>
>_______________________________________________
>
>rules-users mailing list
>
>rules-users@lists.jboss.org <mailto:rules-users@lists.jboss.org>
>
>https://lists.jboss.org/mailman/listinfo/rules-users
>
>  
>
>
>
>
>
>------------------------------------------------------------------------
>
>
>
>
>_______________________________________________
>
>rules-users mailing list
>
>rules-users@lists.jboss.org <mailto:rules-users@lists.jboss.org>
>
>https://lists.jboss.org/mailman/listinfo/rules-users
>
>  
>
>------------------------------------------------------------------------
>
>_______________________________________________
>rules-users mailing list
>rules-users@lists.jboss.org
>https://lists.jboss.org/mailman/listinfo/rules-users
>  
>


--
Edson Tirelli
Software Engineer - JBoss Rules Core Developer
Office: +55 11 3124-6000
Mobile: +55 11 9218-4151
JBoss, a division of Red Hat @ www.jboss.com


_______________________________________________
rules-users mailing list
rules-users@lists.jboss.org
https://lists.jboss.org/mailman/listinfo/rules-users