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https://issues.apache.org/jira/browse/GEODE-697?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15200213#comment-15200213
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Bruce Schuchardt commented on GEODE-697:
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If we ignore the event ID on the secondary we will have more inconsistencies.
If a client did put(x,a) and failed over to another server during the operation
but succeeded in finishing it and then did a put(x,b) it's entirely possible
for the put(x,a) to still be in transit to the secondary from the original
attempt.
Ignoring the event ID on the server cache won't stop it from being rejected by
client queues, either.
> A client thread timing out an operation and performing further operations can
> result in cache inconsistency
> -----------------------------------------------------------------------------------------------------------
>
> Key: GEODE-697
> URL: https://issues.apache.org/jira/browse/GEODE-697
> Project: Geode
> Issue Type: Bug
> Reporter: Dan Smith
> Assignee: Bruce Schuchardt
>
> There is a case where the primary and secondary buckets of a partitioned
> region can become out of sync if a client times out while waiting for a slow
> operation to finish. Here's the scenario:
> 1. A operation is started by the client and gets stuck on the server, for
> example by a slow cache writer. That operation is assigned an EventID with a
> sequence number of 1.
> 2. The client times out.
> 3. The client performs a second operation. That operation gets assigned an
> EventID with a sequence number of 2.
> 4. The second operation is applied on all members. The EventTracker records
> the sequence number 2.
> 5. The original operation continues. It is applied to the primary (because it
> has passed the EventTracker test).
> 6. The original operation is rejected by the EventTracker on the secondary.
> The two copies of the bucket are now inconsistent.
> One possible fix is to change the thread id of the thread on the client when
> the client operation times out. That would ensure that the EventTracker will
> not reject the original operation when it finally goes through, because it
> has a different thread id.
> If an operation is delayed on the server, for example by a very slow cache
> writer, the operation can time out on the client.
> The client can then go on and perform a second operation.
> The problem is that each operation is assigned an event id which is a
> combination of the clients thread id and a sequence number. That second
> operation has a higher sequence number.
> Once the second operation is applied to a region on a given member, the event
> is stored in the EventTracker and that member will reject any lower sequence
> numbers
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