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https://issues.apache.org/jira/browse/HIVE-21225?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17036574#comment-17036574
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Gopal Vijayaraghavan commented on HIVE-21225:
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bq. The overhead compared to the benefit where we use the statuses once per
delta directory (After HIVE-21177) to determine RawFormat seems very high.
This was also a correctness fix even for HDFS, the caching is necessary for the
listing to be exactly once as the older compacted dirs can be deleted while a
query is halfway through this loop (& there's a file-not-found
[~aditya-shah]: Since your numbers seem way off from mine, I suspect you might
be hitting another set of issues here & need a svg from an async-profiler
attached to the AM.
My builds do have HADOOP-16801, which makes a significant difference here.
> ACID: getAcidState() should cache a recursive dir listing locally
> -----------------------------------------------------------------
>
> Key: HIVE-21225
> URL: https://issues.apache.org/jira/browse/HIVE-21225
> Project: Hive
> Issue Type: Improvement
> Components: Transactions
> Reporter: Gopal Vijayaraghavan
> Assignee: Vaibhav Gumashta
> Priority: Major
> Fix For: 4.0.0
>
> Attachments: HIVE-21225.1.patch, HIVE-21225.10.patch,
> HIVE-21225.11.patch, HIVE-21225.12.patch, HIVE-21225.13.patch,
> HIVE-21225.14.patch, HIVE-21225.15.patch, HIVE-21225.15.patch,
> HIVE-21225.16.patch, HIVE-21225.17.patch, HIVE-21225.2.patch,
> HIVE-21225.3.patch, HIVE-21225.4.patch, HIVE-21225.4.patch,
> HIVE-21225.5.patch, HIVE-21225.6.patch, HIVE-21225.7.patch,
> HIVE-21225.7.patch, HIVE-21225.8.patch, HIVE-21225.9.patch, async-pid-44-2.svg
>
>
> Currently getAcidState() makes 3 calls into the FS api which could be
> answered by making a single recursive listDir call and reusing the same data
> to check for isRawFormat() and isValidBase().
> All delta operations for a single partition can go against a single listed
> directory snapshot instead of interacting with the NameNode or ObjectStore
> within the inner loop.
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