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https://issues.apache.org/jira/browse/HIVE-18264?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16388313#comment-16388313
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Vaibhav Gumashta commented on HIVE-18264:
-----------------------------------------

[~daijy] [~thejas] The test failures are not related (unrelated q tests failing 
due to OOM).

> 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: Bug
>            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
>
>
> 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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