Verify causes OutOfMemoryError in BRMS 5

Solution Unverified - Updated

Environment

  • Red Hat JBoss BRMS
    • 5.2.0
    • 5.3.1

Issue

  • After seeing "java.lang.OutOfMemoryError: Java heap space" errors multiple times, JVM options were changed to allow an inital 4GB and maximum 8GB. However, this has not resolved the issue, given that now (only a few days after the increase) the error still occurs. There does not seem to be a consistent trigger for this error.
  • I get OutOfMemoryError in Guvnor but I didn't run test scenarios in the server, Why?
  • A heap dump from an OOME on BRMS 5 shows excessive heap retention generated in org.drools.reteoo.JoinNodeLeftTuple while serving some requests.

Resolution

It is known that Verifier is sometimes very greedy on heap/CPU. We have 2 Bugzillas.

A simple workaround is "don't use Verifier".

Verifier is executed by these operations:

A. [Source]->[Verify] for an Asset（= Verifying an asset）
B. [Edit]->[Select Working Sets]->[Save and Close] (= Verifying asset after applying Working Set)
C. [QA]->[Analysis]->[Run Analysis] (= Verifying a package)

If you are okay with disabling Verifier, you can try a safer approach to avoid any mis-clicking.

  • Edit $JBOSS_HOME/server/$PROFILE/deploy/jboss-brms.war/WEB-INF/web.xml in order to disable Verifier.

from:

  <servlet-mapping>
    <servlet-name>verificationService</servlet-name>
    <url-pattern>/org.drools.guvnor.Guvnor/verificationService</url-pattern>
  </servlet-mapping>

to:

  <!-- <servlet-mapping> -->
  <!--   <servlet-name>verificationService</servlet-name> -->
  <!--   <url-pattern>/org.drools.guvnor.Guvnor/verificationService</url-pattern> -->
  <!-- </servlet-mapping> -->

This will raise an error pop-up instead of executing Verifier when users click the above operations.

Diagnostic Steps

  • (If the trigger operation is not identified) Ask for a heap dump
    • If Verifier is the case, there are many objects (e.g. JoinNodeLeftTuple) and org.drools.verifier.builder.VerifierImpl would apprear in the object tree.
SBR
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