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From "Mithun Radhakrishnan (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-7195) Improve Metastore performance
Date Wed, 11 Jun 2014 23:01:03 GMT

    [ https://issues.apache.org/jira/browse/HIVE-7195?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14028545#comment-14028545
] 

Mithun Radhakrishnan commented on HIVE-7195:
--------------------------------------------

[~sershe]: listPartitions(), etc. do have a max_parts parameter. I'm exploring the possibility
of reducing the thrift traffic for partition-operations, for a given number of partitions.
That would free us up to transfer metadata for more partitions, without fear of the metastore
keeling over from heap-frag, etc.

One way of doing that is to reduce redundancy when specifying multiple partitions. Abstracting
how partitions are specified makes it possible to vary and extend this.

> Improve Metastore performance
> -----------------------------
>
>                 Key: HIVE-7195
>                 URL: https://issues.apache.org/jira/browse/HIVE-7195
>             Project: Hive
>          Issue Type: Improvement
>            Reporter: Brock Noland
>            Priority: Critical
>
> Even with direct SQL, which significantly improves MS performance, some operations take
a considerable amount of time, when there are many partitions on table. Specifically I believe
the issue:
> * When a client gets all partitions we do not send them an iterator, we create a collection
of all data and then pass the object over the network in total
> * Operations which require looking up data on the NN can still be slow since there is
no cache of information and it's done in a serial fashion
> * Perhaps a tangent, but our client timeout is quite dumb. The client will timeout and
the server has no idea the client is gone. We should use deadlines, i.e. pass the timeout
to the server so it can calculate that the client has expired.



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