Barry Oglesby created GEODE-6854:
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Summary: GatewaySender batch conflation can incorrectly conflate
events causing out of order processing
Key: GEODE-6854
URL: https://issues.apache.org/jira/browse/GEODE-6854
Project: Geode
Issue Type: Bug
Components: wan
Reporter: Barry Oglesby
If a batch contains 2 equal update events,
{{AbstractGatewaySenderEventProcessor conflate}} will remove the original event
and add the later event at the end of the list. Depending on the other events
in the list, this could cause the batch to contain events that are out of order.
For example, in this batch containing 6 events before conflation, the last two
events are duplicates of earlier events:
{noformat}
SenderEventImpl[id=EventID[threadID=0x10059|104;sequenceID=2;bucketId=89];action=1;operation=UPDATE;region=/dataStoreRegion;key=Object_6079;shadowKey=16587]
SenderEventImpl[id=EventID[threadID=0x10059|104;sequenceID=3;bucketId=89];action=2;operation=DESTROY;region=/dataStoreRegion;key=Object_6079;shadowKey=16700]
SenderEventImpl[id=EventID[threadID=0x10059|112;sequenceID=9;bucketId=89];action=1;operation=PUTALL_UPDATE;region=/dataStoreRegion;key=Object_7731;shadowKey=16813]
SenderEventImpl[id=EventID[threadID=0x10059|112;sequenceID=12;bucketId=89];action=1;operation=PUTALL_UPDATE;region=/dataStoreRegion;key=Object_6591;shadowKey=16926]
SenderEventImpl[id=EventID[threadID=0x10059|104;sequenceID=3;bucketId=89];action=2;operation=DESTROY;region=/dataStoreRegion;key=Object_6079;shadowKey=16700]
SenderEventImpl[id=EventID[threadID=0x10059|112;sequenceID=9;bucketId=89];action=1;operation=PUTALL_UPDATE;region=/dataStoreRegion;key=Object_7731;shadowKey=16813]
{noformat}
Conflating this batch results in these 4 events:
{noformat}
SenderEventImpl[id=EventID[threadID=0x10059|104;sequenceID=2;bucketId=89];action=1;operation=UPDATE;region=/dataStoreRegion;key=Object_6079;shadowKey=16587]
SenderEventImpl[id=EventID[threadID=0x10059|104;sequenceID=3;bucketId=89];action=2;operation=DESTROY;region=/dataStoreRegion;key=Object_6079;shadowKey=16700]
SenderEventImpl[id=EventID[threadID=0x10059|112;sequenceID=12;bucketId=89];action=1;operation=PUTALL_UPDATE;region=/dataStoreRegion;key=Object_6591;shadowKey=16926]
SenderEventImpl[id=EventID[threadID=0x10059|112;sequenceID=9;bucketId=89];action=1;operation=PUTALL_UPDATE;region=/dataStoreRegion;key=Object_7731;shadowKey=16813]
{noformat}
Notice the shadowKeys and sequenceIds are out of order after the conflation.
Conflation should produce this batch:
{noformat}
SenderEventImpl[id=EventID[threadID=0x10059|104;sequenceID=2;bucketId=89];action=1;operation=UPDATE;region=/dataStoreRegion;key=Object_6079;shadowKey=16587]
SenderEventImpl[id=EventID[threadID=0x10059|104;sequenceID=3;bucketId=89];action=2;operation=DESTROY;region=/dataStoreRegion;key=Object_6079;shadowKey=16700]
SenderEventImpl[id=EventID[threadID=0x10059|112;sequenceID=9;bucketId=89];action=1;operation=PUTALL_UPDATE;region=/dataStoreRegion;key=Object_7731;shadowKey=16813]
SenderEventImpl[id=EventID[threadID=0x10059|112;sequenceID=12;bucketId=89];action=1;operation=PUTALL_UPDATE;region=/dataStoreRegion;key=Object_6591;shadowKey=16926]
{noformat}
This is similar to GEODE-4704, but not exactly the same.
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