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From "Vincent Poon (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (PHOENIX-3815) Only disable indexes on which write failures occurred
Date Tue, 29 Aug 2017 18:01:04 GMT

    [ https://issues.apache.org/jira/browse/PHOENIX-3815?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16145787#comment-16145787
] 

Vincent Poon commented on PHOENIX-3815:
---------------------------------------

[~jamestaylor] now that we've lowered the index write timeout (PHOENIX-3948), I suppose TrackingWriter
isn't as bad.  However, there are still some corner cases where it will be noticeably slower
than ParallelWriter.  Imagine all threads in the writer pool (default of 10) are in use and
there is heavy write traffic - the writes will then be executed serially as threads become
available, and you'd have to wait for each to fail in the worst case where all indexes are
failing.

But I think these might be relatively rare cases.  Also if the failure policy is to disable
the index, then it doesn't matter too much.  Either way, we should at a minimum extract out
the common code in the classes if we're not going to remove one - they pretty much do the
same thing but use a different TaskRunner.

If the failure policy is to leave the index enabled, then you might care about failing fast,
as you could face repeated failures if something is wrong with the index RS.  We could also
have a rate counter for # of failures in a given time window.  If # of failures exceeds that,
we fail fast like ParallelWriter.  Otherwise, use TrackingWriter logic in the normal happy
case.  But again, only matters if you plan to leave the index enabled.

> Only disable indexes on which write failures occurred
> -----------------------------------------------------
>
>                 Key: PHOENIX-3815
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-3815
>             Project: Phoenix
>          Issue Type: Bug
>            Reporter: James Taylor
>            Assignee: Vincent Poon
>             Fix For: 4.12.0
>
>         Attachments: PHOENIX-3815.v1.patch
>
>
> We currently disable all indexes if any of them fail to be written to. We really only
should disable the one in which the write failed.



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