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https://issues.apache.org/jira/browse/PHOENIX-3121?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15399735#comment-15399735
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James Taylor commented on PHOENIX-3121:
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On second thought, I don't think this is an issue, [~an...@apache.org]. Since
the offset is causing us to *skip* the row, it won't make it in the rows
returned back to the client and thus won't contributed to the population of the
scanner cache. I think in theory we could not do our hack if there's an offset
being passed to the server, but it won't hurt anything even if we do it.
That got me thinking about reverse scan in combination with offset. Do we have
tests for this case? We might be ok, as we only use a reverse scan when there's
an ORDER BY ... DESC, in which case if we pass an offset to the server, I think
it would do the correct thing (skip the initial rows starting from the largest
ones).
> Queries with filter and reverse scan failing when limit is a multiple of
> scanner cache size
> -------------------------------------------------------------------------------------------
>
> Key: PHOENIX-3121
> URL: https://issues.apache.org/jira/browse/PHOENIX-3121
> Project: Phoenix
> Issue Type: Bug
> Reporter: Samarth Jain
> Assignee: Samarth Jain
> Fix For: 4.8.0
>
> Attachments: PHOENIX-3121.patch, PHOENIX-3121_v2.patch
>
>
> {code}
> org.apache.hadoop.hbase.UnknownScannerException:
> org.apache.hadoop.hbase.UnknownScannerException: Unknown scanner '644116'.
> This can happen due to any of the following reasons: a) Scanner id given is
> wrong, b) Scanner lease expired because of long wait between consecutive
> client checkins, c) Server may be closing down, d) RegionServer restart
> during upgrade.
> If the issue is due to reason (b), a possible fix would be increasing the
> value of'hbase.client.scanner.timeout.period' configuration.
> at
> org.apache.hadoop.hbase.regionserver.HRegionServer.scan(HRegionServer.java:3228)
> at
> org.apache.hadoop.hbase.protobuf.generated.ClientProtos$ClientService$2.callBlockingMethod(ClientProtos.java:32492)
> at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2208)
> at org.apache.hadoop.hbase.ipc.CallRunner.run(CallRunner.java:104)
> at
> org.apache.hadoop.hbase.ipc.RpcExecutor.consumerLoop(RpcExecutor.java:133)
> at org.apache.hadoop.hbase.ipc.RpcExecutor$1.run(RpcExecutor.java:108)
> at java.lang.Thread.run(Thread.java:745)
> {code}
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