Barry Oglesby created GEODE-4704:
------------------------------------
Summary: GatewaySender batch conflation can incorrectly conflate
events causing out of order processing
Key: GEODE-4704
URL: https://issues.apache.org/jira/browse/GEODE-4704
Project: Geode
Issue Type: Bug
Components: wan
Reporter: Barry Oglesby
In the current implementation of \{{AbstractGatewaySenderEventProcessor
conflate}} can incorrectly conflate two create events on the same key.
The else clause of the conflate method (meaning the event is not conflatable)
assumes there isn't already a event with the same region, key and operation in
the map. It just does a put:
{noformat}
ConflationKey key = new ConflationKey(gsEvent.getRegion().getFullPath(),
gsEvent.getKeyToConflate(), gsEvent.getOperation());
conflatedEventsMap.put(key, gsEvent);
{noformat}
In certain cases, there could already be a create event on the same region, key
and operation in the batch, so the previous one gets replaced by the later once
which causes the events to be processed out of order.
These 4 events:
{noformat}
SenderEventImpl[id=EventIDid=57bytes;threadID=0x10018|112;sequenceID=100;bucketId=24];operation=CREATE;region=/dataStoreRegion;key=Object_13964;shadowKey=27709]
SenderEventImpl[id=EventIDid=57bytes;threadID=0x10018|112;sequenceID=101;bucketId=24];operation=CREATE;region=/dataStoreRegion;key=Object_14024;shadowKey=27822]
SenderEventImpl[id=EventIDid=57bytes;threadID=0x10018|112;sequenceID=102;bucketId=24];operation=DESTROY;region=/dataStoreRegion;key=Object_13964;shadowKey=27935]
SenderEventImpl[id=EventIDid=57bytes;threadID=0x10018|112;sequenceID=104;bucketId=24];operation=CREATE;region=/dataStoreRegion;key=Object_14024;shadowKey=28161]
{noformat}
Become these 3 events:
{noformat}
SenderEventImpl[id=EventIDid=57bytes;threadID=0x10018|112;sequenceID=100;bucketId=24];operation=CREATE;region=/dataStoreRegion;key=Object_13964;shadowKey=27709]
SenderEventImpl[id=EventIDid=57bytes;threadID=0x10018|112;sequenceID=104;bucketId=24];operation=CREATE;region=/dataStoreRegion;key=Object_14024;shadowKey=28161]
SenderEventImpl[id=EventIDid=57bytes;threadID=0x10018|112;sequenceID=102;bucketId=24];operation=DESTROY;region=/dataStoreRegion;key=Object_13964;shadowKey=27935]
{noformat}
Notice the shadowKeys and sequenceIds are out of order after the conflation.
The fix will be to include the shadow key in hashCode and equals in the case
where the event is not conflatable.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
