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https://issues.apache.org/jira/browse/HIVE-12631?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15874437#comment-15874437
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Teddy Choi commented on HIVE-12631:
-----------------------------------
I made LLAP IO to merge ACID delta and base from a file system. But
implementing ACID delta cache will take longer time. So I will make a new issue
to cache ACID, and leave this issue to read from a file system. Thank you for
your feedbacks, [~sershe], [~gopalv], [~hagleitn].
> LLAP: support ORC ACID tables
> -----------------------------
>
> Key: HIVE-12631
> URL: https://issues.apache.org/jira/browse/HIVE-12631
> Project: Hive
> Issue Type: Bug
> Components: llap, Transactions
> Reporter: Sergey Shelukhin
> Assignee: Teddy Choi
> Attachments: HIVE-12631.1.patch, HIVE-12631.2.patch,
> HIVE-12631.3.patch
>
>
> LLAP uses a completely separate read path in ORC to allow for caching and
> parallelization of reads and processing. This path does not support ACID. As
> far as I remember ACID logic is embedded inside ORC format; we need to
> refactor it to be on top of some interface, if practical; or just port it to
> LLAP read path.
> Another consideration is how the logic will work with cache. The cache is
> currently low-level (CB-level in ORC), so we could just use it to read bases
> and deltas (deltas should be cached with higher priority) and merge as usual.
> We could also cache merged representation in future.
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