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https://issues.apache.org/jira/browse/DRILL-4786?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15396296#comment-15396296
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ASF GitHub Bot commented on DRILL-4786:
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Github user jinfengni commented on the issue:
https://github.com/apache/drill/pull/553
+1
LGTM.
> Improve metadata cache performance for queries with multiple partitions
> -----------------------------------------------------------------------
>
> Key: DRILL-4786
> URL: https://issues.apache.org/jira/browse/DRILL-4786
> Project: Apache Drill
> Issue Type: Improvement
> Components: Metadata, Query Planning & Optimization
> Affects Versions: 1.7.0
> Reporter: Aman Sinha
> Assignee: Aman Sinha
>
> Consider queries of the following type run against Parquet data with
> metadata caching:
> {noformat}
> SELECT col FROM `A` WHERE dir0 = 'B`' AND dir1 IN ('1', '2', '3')
> {noformat}
> For such queries, Drill will read the metadata cache file from the top level
> directory 'A', which is not very efficient since we are only interested in
> the files from some subdirectories of 'B'. DRILL-4530 improves the
> performance of such queries when the leaf level directory is a single
> partition. Here, there are 3 subpartitions due to the IN list. We can
> build upon the DRILL-4530 enhancement by at least reading the cache file from
> the immediate parent level `/A/B` instead of the top level.
> The goal of this JIRA is to improve performance for such types of queries.
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