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https://issues.apache.org/jira/browse/DRILL-2517?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14375451#comment-14375451
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Adam Gilmore commented on DRILL-2517:
-------------------------------------
https://github.com/AdamPD/drill/commit/ac68320dcdba55f1a148bed925cc6dd24c4f120f
I started a bit of work on solving this particular issue. In this case, the
partition pruning runs before the DrillPushProjIntoScan rule.
I'm not entirely happy with this implementation, though:
1. Currently FileGroupScan has the "supportsPartitionFilterPushdown" method
(which is no longer being called). I would have thought the FormatPlugin would
be the best place for this, but I don't fully understand the reasons behind it.
2. I added modifySelection to DrillTable. I note AbstractFileGroupScan has
something very similar, but it also feels a bit dirty as it was immutable
before. There doesn't seem to be a way around it though without going straight
to a DrillScanRel, which seems not the job of the partition pruning.
It would be good to get some comments on this from those more familiar with the
partition pruning.
> Partition pruning still reading files during planning
> -----------------------------------------------------
>
> Key: DRILL-2517
> URL: https://issues.apache.org/jira/browse/DRILL-2517
> Project: Apache Drill
> Issue Type: Bug
> Components: Query Planning & Optimization
> Affects Versions: 0.7.0, 0.8.0
> Reporter: Adam Gilmore
> Assignee: Jinfeng Ni
>
> Partition pruning still tries to read Parquet files during the planning stage
> even though they don't match the partition filter.
> For example:
> {code}
> 0: jdbc:drill:zk=local> select sum(price) from dfs.tmp.purchases where dir0 =
> 1;
> Query failed: IllegalArgumentException: file:/tmp/purchases/4/0_0_0.parquet
> is not a Parquet file (too small)
> {code}
> The reason is that the partition pruning happens after the Parquet plugin
> tries to read the footer of each file.
> Ideally, partition pruning would happen first before the format plugin gets
> involved.
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