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https://issues.apache.org/jira/browse/HIVE-12631?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15897835#comment-15897835
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Eugene Koifman edited comment on HIVE-12631 at 3/6/17 7:04 PM:
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[~teddy.choi]
Since this is only targeting acid 2.0, there should be 3 types of files (dirs):
base, delta and delete_delta. There should not be any difference regarding
caching base vs delta.
In fact, longer term we may even simplify this to just base and delete_delta so
it may be better to just postpone the the delta caching part of this
was (Author: ekoifman):
[~teddy.choi]
Since this is only targeting acid 2.0, there should be 3 types of files (dirs):
base, delta and delete_delta. There should not be any difference regarding
caching base vs delta.
> 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, HIVE-12631.4.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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