[jira] [Resolved] (HIVE-23764) Remove unnecessary getLastFlushLength when checking delete delta files

["Peter Vary (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-23764?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Peter Vary resolved HIVE-23764.
-------------------------------
    Fix Version/s: 4.0.0
         Assignee: Rajesh Balamohan  (was: Peter Vary)
       Resolution: Fixed

Pushed to master.

Thanks for the patch [~rajesh.balamohan] and [~klcopp] for the review!

> Remove unnecessary getLastFlushLength when checking delete delta files
> ----------------------------------------------------------------------
>
>                 Key: HIVE-23764
>                 URL: https://issues.apache.org/jira/browse/HIVE-23764
>             Project: Hive
>          Issue Type: Improvement
>          Components: Transactions
>            Reporter: Peter Vary
>            Assignee: Rajesh Balamohan
>            Priority: Major
>              Labels: pull-request-available
>             Fix For: 4.0.0
>
>          Time Spent: 20m
>  Remaining Estimate: 0h
>
> VectorizedOrcAcidRowBatchReader$ColumnizedDeleteEventRegistry calls OrcAcidUtils.getLastFlushLength for every delete delta file.
> Even the comment says:
> {code}
>               // NOTE: Calling last flush length below is more for future-proofing when we have
>               // streaming deletes. But currently we don't support streaming deletes, and this can
>               // be removed if this becomes a performance issue.
> {code}
> If we have a table with 5 updates (1 base + 5 delta + 5 delete_delta), then for every base + delta dir we will check all of the delete_delta directories, and check the getLastFlushLength method which will result in 6*5=30 unnecessary NN/S3 calls.
> We should remove the check as already proposed in the comment.



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