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https://issues.apache.org/jira/browse/HIVE-18264?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16397578#comment-16397578
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Vaibhav Gumashta commented on HIVE-18264:
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v7 rebased on master.
> CachedStore: Store cached partitions/col stats within the table cache and
> make prewarm non-blocking
> ---------------------------------------------------------------------------------------------------
>
> Key: HIVE-18264
> URL: https://issues.apache.org/jira/browse/HIVE-18264
> Project: Hive
> Issue Type: Sub-task
> Reporter: Vaibhav Gumashta
> Assignee: Vaibhav Gumashta
> Priority: Major
> Attachments: HIVE-18264.1.patch, HIVE-18264.2.patch,
> HIVE-18264.3.patch, HIVE-18264.4.patch, HIVE-18264.5.patch,
> HIVE-18264.6.patch, HIVE-18264.7.patch
>
>
> Currently we have a separate cache for partitions and partition col stats
> which results in some calls iterating through each of these for
> retrieving/updating. For example, to modify a partition col stat, currently
> we need to lock table, partition and partition col stats caches which are all
> separate hashmaps. We can get better performance by organizing
> hierarchically. For example, we can have a partition, partition col stats and
> table col stats cache per table to improve on the previous mechanisms. This
> will also result in better concurrency, since now instead of locking the
> whole cache, we can selectively lock the table cache and modify multiple
> tables in parallel.
> In addition, currently, the prewarm mechanism populates all the caches
> initially (it skips tables that do not pass whitelist/blacklist filter) and
> it is a blocking call. This patch also makes prewarm non-blocking so that the
> calls for tables that are already cached can be served from the memory and
> the ones that are not can be served from the rdbms.
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