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https://issues.apache.org/jira/browse/HIVE-18449?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16329900#comment-16329900
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Vihang Karajgaonkar commented on HIVE-18449:
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Thanks for your inputs [~thejas] I agree adding new configs is a problem in
general but in this particular case I think it is hard to anticipate with 100%
certainty that there are no issues with active-active HMS configuration esp in
a heavily used environment. The fix for HIVE-16886 went in Hive 3.0 so Hive 2.x
is still vulnerable to the duplicate event id issue. Also, I am not a 100% sure
but I remember there was some discussion on whether the fix for HIVE-16886
worked well for all the supported databases as well (I may be wrong on this).
We had also seen in our testing that datanucleus cacheing was causing come
problems in active-active mode as well but we could not reproduce it later.
Having a config option helps alleviate the problem and provides an easy
workaround until the issue is fixed. We can keep the existing behavior to
random URIs as such using a default pluggable implementation on similar lines
as [~szehon]'s patch. In general I think its a good idea to have a pluggable
URI resolver which can be extended in future for usecases like (smart load
balancing based on some metric) or automatic HMS service discovery in the
future.
> Add configurable policy for choosing the HMS URI from hive.metastore.uris
> -------------------------------------------------------------------------
>
> Key: HIVE-18449
> URL: https://issues.apache.org/jira/browse/HIVE-18449
> Project: Hive
> Issue Type: Improvement
> Components: Metastore
> Reporter: Sahil Takiar
> Assignee: Janaki Lahorani
> Priority: Major
>
> HIVE-10815 added logic to randomly choose a HMS URI from
> {{hive.metastore.uris}}. It would be nice if there was a configurable policy
> that determined how a URI is chosen from this list - e.g. one option can be
> to randomly pick a URI, another option can be to choose the first URI in the
> list (which was the behavior prior to HIVE-10815).
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