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Posted to issues@drill.apache.org by "Jacques Nadeau (JIRA)" <ji...@apache.org> on 2014/11/17 02:11:33 UTC
[jira] [Resolved] (DRILL-1362) Count(nullable-column) is
incorrectly pushed into group scan operator
[ https://issues.apache.org/jira/browse/DRILL-1362?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Jacques Nadeau resolved DRILL-1362.
-----------------------------------
Resolution: Fixed
> Count(nullable-column) is incorrectly pushed into group scan operator
> ---------------------------------------------------------------------
>
> Key: DRILL-1362
> URL: https://issues.apache.org/jira/browse/DRILL-1362
> Project: Apache Drill
> Issue Type: Bug
> Components: Execution - Operators
> Affects Versions: 0.4.0
> Reporter: Aman Sinha
> Fix For: 0.7.0
>
>
> The following query on TPC-DS table web_returns produces wrong result because the aggregate count(wr_return_quantity) gets pushed into the parquet group scan operator even though wr_return_quantity is nullable and apparently the parquet metadata does not have stats on nullable column.
> 0: jdbc:drill:zk=local> select count(wr_return_quantity) from web_returns;
> +------------+
> | EXPR$0 |
> +------------+
> | 71763 |
> +------------+
> 0: jdbc:drill:zk=local> explain plan for select count(wr_return_quantity) from web_returns;
> {code:sql}
> +------------+------------+
> | text | json |
> +------------+------------+
> | 00-00 Screen
> 00-01 Project(EXPR$0=[$0])
> 00-02 Scan(groupscan=[org.apache.drill.exec.store.pojo.PojoRecordReader@e4acaad])
> {code}
> For reference, here are the correct results:
> tpcds=# select count(wr_return_quantity) from web_returns;
> count
> -------
> 68616
> (1 row)
> tpcds=# select count(*) from web_returns;
> count
> -------
> 71763
> (1 row)
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