StackOverflowError in BetaNode.networkUpdated()

[vaibhav-logik]

Caused by: java.lang.StackOverflowError
at org.drools.core.reteoo.BetaNode.equals(BetaNode.java:628)
at org.drools.core.common.UpdateContext.isVisiting(UpdateContext.java:33)
at org.drools.core.reteoo.BetaNode.networkUpdated(BetaNode.java:525)
at org.drools.core.reteoo.BetaNode.networkUpdated(BetaNode.java:526)
at org.drools.core.reteoo.BetaNode.networkUpdated(BetaNode.java:526)
at org.drools.core.reteoo.BetaNode.networkUpdated(BetaNode.java:526)
at org.drools.core.reteoo.BetaNode.networkUpdated(BetaNode.java:526)
.........

Test case
rule "101 - Test Rule"
no-loop true
when
$field2: PicklistField(getName()=="field2" && getHasValue())
$field3: PicklistField(getName()=="field3" && getHasValue())
$field4: PicklistField(getName()=="field4" && getHasValue())
$field5: PicklistField(getName()=="field5" && getHasValue())
$field6: PicklistField(getName()=="field6" && getHasValue())
exists(
(
PicklistField(getName()=="field2" && getStringValue() != "X")
|| PicklistField(getName()=="field3" && getStringValue() != "X")
|| PicklistField(getName()=="field4" && getStringValue() != "X")
|| PicklistField(getName()=="field5" && getStringValue() != "X")
|| PicklistField(getName()=="field6" && getStringValue() != "X")
)
&&
(
PicklistField(getName()=="field2" && getStringValue() != "X")
|| PicklistField(getName()=="field3" && getStringValue() != "X")
|| PicklistField(getName()=="field4" && getStringValue() != "X")
|| PicklistField(getName()=="field5" && getStringValue() != "X")
|| PicklistField(getName()=="field6" && getStringValue() != "X")
)
&&
(
PicklistField(getName()=="field2" && getStringValue() != "X")
|| PicklistField(getName()=="field3" && getStringValue() != "X")
|| PicklistField(getName()=="field4" && getStringValue() != "X")
|| PicklistField(getName()=="field5" && getStringValue() != "X")
|| PicklistField(getName()=="field6" && getStringValue() != "X")
)
&&
(
PicklistField(getName()=="field2" && getStringValue() != "X")
|| PicklistField(getName()=="field3" && getStringValue() != "X")
|| PicklistField(getName()=="field4" && getStringValue() != "X")
|| PicklistField(getName()=="field5" && getStringValue() != "X")
)
&&
(
PicklistField(getName()=="field2" && getStringValue() != "X")
|| PicklistField(getName()=="field3" && getStringValue() != "X")
|| PicklistField(getName()=="field4" && getStringValue() != "X")
|| PicklistField(getName()=="field5" && getStringValue() != "X")
)
&&
(
PicklistField(getName()=="field2" && getStringValue() != "X")
|| PicklistField(getName()=="field3" && getStringValue() != "X")
|| PicklistField(getName()=="field4" && getStringValue() != "X")
|| PicklistField(getName()=="field5" && getStringValue() != "X")
)
)
then
end

[yesamer]

@vaibhav-logik Can you please share more context? Which drools version are you using?

[vaibhav-logik]

@vaibhav-logik Can you please share more context? Which drools version are you using?

we are using 7.68.0.Final

[tkobayas]

@vaibhav-logik

Nested ORs in AND can create huge permutations in KieBase building. In this case, The exists() has 6 AND groups: 3 groups with 5 OR alternatives + 3 groups with 4 OR alternatives. It results in 5 * 5 * 5 * 4 * 4 * 4 = 8,000 permutations. Then it creates a linear chain of 8,000 NotNodes, which will trigger StackOverflowError/OutOfMemoryError.

I recommend to rewrite the rule. exists(A && B) is semantically equivalent to exists(A) && exists(B). So the rule can be split into separate exists() conditions:

  exists(
      PicklistField(getName()=="field2" && getStringValue() != "X")
      || PicklistField(getName()=="field3" && getStringValue() != "X")
      || PicklistField(getName()=="field4" && getStringValue() != "X")
      || PicklistField(getName()=="field5" && getStringValue() != "X")
      || PicklistField(getName()=="field6" && getStringValue() != "X")
  )
  exists(
      PicklistField(getName()=="field2" && getStringValue() != "X")
      || PicklistField(getName()=="field3" && getStringValue() != "X")
      || PicklistField(getName()=="field4" && getStringValue() != "X")
      || PicklistField(getName()=="field5" && getStringValue() != "X")
      || PicklistField(getName()=="field6" && getStringValue() != "X")
  )
  ... repeat for each group

It would significantly reduce the use of stack/heap. Please try.

[vaibhav-logik]

Thank you @tkobayas - will surely try and update here