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https://issues.apache.org/jira/browse/HBASE-5974?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13479326#comment-13479326
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stack commented on HBASE-5974:
------------------------------
Thanks for reminding me about this important issue Anoop. Lets get it into
trunk at least (Should be a blocker on 0.96).
Minor: Do you foresee the sequencing being used other than in scanners (Its
implemented in ScannerCallable only at moment)? If NOT, would
OutOfOrderNextException or OutOfOrderScannerNextException be a better name than
CallSequenceOutOfOrderException? If you do this, would suggest changing param
names from callSeq to nextSeq? The former is generic.
Is CallSequenceOutOfOrderException an exception that will bubble up into the
application or is the client its intended audience? If so, should we annotate
it @InterfaceAudience.Private as Abortable is for instance?
{code}
+ if ((cause == null || (!(cause instanceof
NotServingRegionException)
+ && !(cause instanceof RegionServerStoppedException)))
+ && !(e instanceof CallSequenceOutOfOrderException)) {
{code}
Would it make sense testing ! DoNotRetryIOException rather than calling out the
two exceptions above? Would that be too broad? Otherwise, wondering if these
two exceptions should inherit from a common base class given they are getting
this special treatment. Not important. Just a thought.
Check your comments. You seem to be saying 'scan' when you mean 'next'.
For example, this comment:
{code}
+ // increment the callSeq which will be getting used for the next
time scan() call to
+ // the RS.In case of a timeout this increment should not happen so
that the next
+ // trial also will be done with the same callSeq.
{code}
Regards the above comment, is there a sentence missing on what happens if we go
back w/ the same callseq? Maybe have another go at this whole comment... it
could be a bit clearer. Thanks.
Committing this set of comments.... more to come.
> Scanner retry behavior with RPC timeout on next() seems incorrect
> -----------------------------------------------------------------
>
> Key: HBASE-5974
> URL: https://issues.apache.org/jira/browse/HBASE-5974
> Project: HBase
> Issue Type: Bug
> Components: Client, regionserver
> Affects Versions: 0.90.7, 0.92.1, 0.94.0, 0.96.0
> Reporter: Todd Lipcon
> Assignee: Anoop Sam John
> Priority: Critical
> Fix For: 0.96.0
>
> Attachments: 5974_94-V4.patch, 5974_trunk.patch, 5974_trunk-V2.patch,
> HBASE-5974_0.94.patch, HBASE-5974_94-V2.patch, HBASE-5974_94-V3.patch
>
>
> I'm seeing the following behavior:
> - set RPC timeout to a short value
> - call next() for some batch of rows, big enough so the client times out
> before the result is returned
> - the HConnectionManager stuff will retry the next() call to the same server.
> At this point, one of two things can happen: 1) the previous next() call will
> still be processing, in which case you get a LeaseException, because it was
> removed from the map during the processing, or 2) the next() call will
> succeed but skip the prior batch of rows.
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