Out of memory caused by RuleTerminalNodeLeftTuple after upgrade to 7.59.0.Final

[pep...@gmail.com]

Hello

we upgraded from 7.3.0.Final to 7.59.0.Final.

Now we get OutOfMemory exception in Heap space because of endless creation of RuleTerminalNodeLeftTuple objects that belong to a single rule.

I was reading the release notes but found no clue.

Please can you point me to a possible cause?

This was not happenning in 7.3.0.Final.

Is there a safer version between 7.3 and 7.59?

We are afraid what else could happen in our other ~3000 rules.

WORKAROUND:

It is unsettling that there is a workaround.

(rule and stacktrace is provided below) 

When we rewrite the condition

$ac : AssetCard(_parent == $as, groupCode2 in ("A", "B", "C")) @watch(groupCode2)

NOT to use the IN operator but to use ||

$ac : AssetCard(_parent == $as, groupCode2 == "A" || groupCode2 == "B" || groupCode2 == "C") @watch(groupCode2)

it works normally.

CONTEXT:

We upgraded from 7.3.0.Final to 7.59.0.Final in hope to get rid of memory leaks.

With 7.3.0.Final we had problems with KieContainer holding references to Kie sessions, even after sessions were disposed. This (or similar issue) was fixed in 7.2, but still occured.

(https://issues.redhat.com/browse/DROOLS-1655). After upgrading to 7.59.0.Final the problem dissappeared

DETAILS:

It happens after AssetCard object is removed and a new one is inserted (+ parent and child objects are updated/deleted/inserted).

After that, the memory is filled up very fast with millions of RuleTerminalNodeLeftTuple.

The rule

rule "XXX"

  agenda-group "Calculation"

  salience 999999999

  no-loop

when

  $bc : VarBusinessCase()

  $vdt : LocalDateTimeVariable(name == V.validityDateTime, value != null) @watch(value)

  $ovt : LocalDateTimeVariable(name == V.offerValidityTo) @watch(value)

  $as : Asset(_parent == $bc)

  $ac : AssetCard(_parent == $as, groupCode2 in ("A", "B", "C")) @watch(groupCode2)

then

  modify($ovt){setValue($vdt.getValue().plusDays(30))}

end

There is circular @watch(value) and modify($ovt).setValue, but there is also no-loop.

Stack trace

getStagedType:357, TupleSetsImpl (org.drools.core.common)

addInsert:85, TupleSetsImpl (org.drools.core.common)

insertChildLeftTuple:482, PhreakJoinNode (org.drools.core.phreak)

doRightInserts:160, PhreakJoinNode (org.drools.core.phreak)

doNode:67, PhreakJoinNode (org.drools.core.phreak)

switchOnDoBetaNode:569, RuleNetworkEvaluator (org.drools.core.phreak)

evalBetaNode:555, RuleNetworkEvaluator (org.drools.core.phreak)

evalNode:382, RuleNetworkEvaluator (org.drools.core.phreak)

innerEval:342, RuleNetworkEvaluator (org.drools.core.phreak)

outerEval:178, RuleNetworkEvaluator (org.drools.core.phreak)

evaluateNetwork:136, RuleNetworkEvaluator (org.drools.core.phreak)

evaluateNetwork:73, RuleExecutor (org.drools.core.phreak)

evaluateEagerList:681, DefaultAgenda (org.drools.core.common)

fireLoop:863, DefaultAgenda (org.drools.core.common)

internalFireAllRules:816, DefaultAgenda (org.drools.core.common)

fireAllRules:808, DefaultAgenda (org.drools.core.common)

internalFireAllRules:1343, StatefulKnowledgeSessionImpl (org.drools.core.impl)

fireAllRules:1334, StatefulKnowledgeSessionImpl (org.drools.core.impl)

fireAllRules:1322, StatefulKnowledgeSessionImpl (org.drools.core.impl)

Thank you in advance,

Kind regards,

Peter

[Toshiya Kobayashi]

Hi Peter,

Could you kindly create and attach a reproducer (= a simple project which reproduces the issue)?

I tried to simulate what you wrote but couldn't reproduce the issue on my end (Just FYI, attached Ex-RuleTerminalNodeLeftTuple-issue-7.59.zip).

Thanks!

Toshiya

2021年10月19日火曜日 23:44:51 UTC+9 pep...@gmail.com:

[Peter Martinovič]

Hello Toshiya

Right now I am not able to focus on creating a reproducer, hopefully it will be possible later.

FYI it seems that it does not happen in 7.45.0.Final.

Thank you,

Peter

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[Peter Martinovič]

Hello Toshiya,

Please find the reproducer attached.

Thank you,

Peter

On Wed, Oct 20, 2021 at 7:20 AM Toshiya Kobayashi <toshiyak...@gmail.com> wrote:

--

[Toshiya Kobayashi]

Thank you very much for the reproducer, Peter.

I can reproduce the issue with it on my end now. I'll investigate and keep you posted.

Regards,

Toshiya

2021年10月22日金曜日 5:21:42 UTC+9 pep...@gmail.com:

[Toshiya Kobayashi]

Filed a JIRA. Will work on it.

https://issues.redhat.com/browse/DROOLS-6684

Thanks!

Toshiya

2021年10月25日月曜日 10:02:58 UTC+9 Toshiya Kobayashi: