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From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (DRILL-4053) Reduce metadata cache file size
Date Fri, 13 Nov 2015 22:27:11 GMT

    [ https://issues.apache.org/jira/browse/DRILL-4053?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15004819#comment-15004819

ASF GitHub Bot commented on DRILL-4053:

Github user StevenMPhillips commented on the pull request:

    Do you have any numbers to illustrate how much of a performance improvement this change

> Reduce metadata cache file size
> -------------------------------
>                 Key: DRILL-4053
>                 URL: https://issues.apache.org/jira/browse/DRILL-4053
>             Project: Apache Drill
>          Issue Type: Improvement
>          Components: Metadata
>    Affects Versions: 1.3.0
>            Reporter: Parth Chandra
>            Assignee: Parth Chandra
>             Fix For: 1.4.0
> The parquet metadata cache file has fair amount of redundant metadata that causes the
size of the cache file to bloat. Two things that we can reduce are :
> 1) Schema is repeated for every row group. We can keep a merged schema (similar to what
was discussed for insert into functionality) 2) The max and min value in the stats are used
for partition pruning when the values are the same. We can keep the maxValue only and that
too only if it is the same as the minValue.

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