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From "Eugene Koifman (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-12631) LLAP: support ORC ACID tables
Date Tue, 06 Jun 2017 15:33:18 GMT

    [ https://issues.apache.org/jira/browse/HIVE-12631?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16039094#comment-16039094
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Eugene Koifman commented on HIVE-12631:
---------------------------------------

[~teddy.choi] could you clarify the changes in VectorizedOrcAcidRowBatchReader.  It already
returns data with Delete events applied.  Why does OrcAcidEncodedDataConsumer do the same.
for example
{noformat}
// we always want to read all the delete delta files.
deleteEventReaderOptions.range(0, Long.MAX_VALUE);
{noformat}
seems like a bug for bug copy&paste

What exactly is being cached?

> 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-12631.10.patch, HIVE-12631.1.patch, HIVE-12631.2.patch, HIVE-12631.3.patch,
HIVE-12631.4.patch, HIVE-12631.5.patch, HIVE-12631.6.patch, HIVE-12631.7.patch, HIVE-12631.8.patch,
HIVE-12631.8.patch, HIVE-12631.9.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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