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https://issues.apache.org/jira/browse/HIVE-23764?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17149471#comment-17149471
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Peter Vary commented on HIVE-23764:
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[~rajesh.balamohan]: I see that in HIVE-23597 we have issues with some tests.
Also caching the OrcTail might be better placed in LLAP IO, and [~szita] is
working on a possible solution.
What do you think about pushing this change, and if we hit some road-block with
the LLAP IO solution then we might pick up HIVE-23597 again?
Thanks,
Peter
> 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: Peter Vary
> Priority: Major
> Labels: pull-request-available
> Time Spent: 10m
> 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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