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https://issues.apache.org/jira/browse/HBASE-11295?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14017817#comment-14017817
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Anoop Sam John commented on HBASE-11295:
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As in Filte waiting happens, client times out and do retry. If this retry is
allowed, we will fail returning some rows. That is why we added the next seq
no#. In this case throwing exception is desired behaviour. On seeing this
exception the client will restart with the initial request . U can see thos
logs? If ur filter logic is going to be time taking, increase the client
timeout.
> Long running scan produces OutOfOrderScannerNextException
> ---------------------------------------------------------
>
> Key: HBASE-11295
> URL: https://issues.apache.org/jira/browse/HBASE-11295
> Project: HBase
> Issue Type: Bug
> Components: regionserver
> Affects Versions: 0.96.0
> Reporter: Jeff Cunningham
> Attachments: OutOfOrderScannerNextException.tar.gz
>
>
> Attached Files:
> HRegionServer.java - instramented from 0.96.1.1-cdh5.0.0
> HBaseLeaseTimeoutIT.java - reproducing JUnit 4 test
> WaitFilter.java - Scan filter (extends FilterBase) that overrides
> filterRowKey() to sleep during invocation
> SpliceFilter.proto - Protobuf defintiion for WaitFilter.java
> OutOfOrderScann_InstramentedServer.log - instramented server log
> Steps.txt - this note
> Set up:
> In HBaseLeaseTimeoutIT, create a scan, set the given filter (which sleeps in
> overridden filterRowKey() method) and set it on the scan, and scan the table.
> This is done in test client_0x0_server_150000x10().
> Here's what I'm seeing (see also attached log):
> A new request comes into server (ID 1940798815214593802 -
> RpcServer.handler=96) and a RegionScanner is created for it, cached by ID,
> immediately looked up again and cached RegionScannerHolder's nextCallSeq
> incremeted (now at 1).
> The RegionScan thread goes to sleep in WaitFilter#filterRowKey().
> A short (variable) period later, another request comes into the server (ID
> 8946109289649235722 - RpcServer.handler=98) and the same series of events
> happen to this request.
> At this point both RegionScanner threads are sleeping in
> WaitFilter.filterRowKey(). After another period, the client retries another
> scan request which thinks its next_call_seq is 0. However, HRegionServer's
> cached RegionScannerHolder thinks the matching RegionScanner's nextCallSeq
> should be 1.
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