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https://issues.apache.org/jira/browse/DRILL-4147?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15402510#comment-15402510
]
ASF GitHub Bot commented on DRILL-4147:
---------------------------------------
Github user sudheeshkatkam commented on a diff in the pull request:
https://github.com/apache/drill/pull/555#discussion_r73022625
--- Diff:
exec/java-exec/src/test/java/org/apache/drill/TestUnionDistinct.java ---
@@ -821,4 +826,34 @@ public void testGroupByUnionDistinct() throws
Exception {
.build()
.run();
}
+
+ @Test // DRILL-4147 // union-distinct base case
+ public void testDrill4147_1() throws Exception {
+ final String l =
FileUtils.getResourceAsFile("/multilevel/parquet/1994").toURI().toString();
+ final String r =
FileUtils.getResourceAsFile("/multilevel/parquet/1995").toURI().toString();
+
+ final String query = String.format("SELECT o_custkey FROM
dfs_test.`%s` \n" +
+ "Union distinct SELECT o_custkey FROM dfs_test.`%s`", l, r);
+
+ // Validate the plan
+ final String[] expectedPlan =
{"(?s)UnionExchange.*HashAgg.*HashToRandomExchange.*UnionAll.*"};
+ final String[] excludedPlan = {};
+
+ test(sliceTargetSmall);
--- End diff --
These two calls should be inside the try block?
> Union All operator runs in a single fragment
> --------------------------------------------
>
> Key: DRILL-4147
> URL: https://issues.apache.org/jira/browse/DRILL-4147
> Project: Apache Drill
> Issue Type: Bug
> Reporter: amit hadke
> Assignee: Aman Sinha
>
> A User noticed that running select from a single directory is much faster
> than union all on two directories.
> (https://drill.apache.org/blog/2014/12/09/running-sql-queries-on-amazon-s3/#comment-2349732267)
>
> It seems like UNION ALL operator doesn't parallelize sub scans (its using
> SINGLETON for distribution type). Everything is ran in single fragment.
> We may have to use SubsetTransformer in UnionAllPrule.
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