Github user vdiravka commented on a diff in the pull request:
https://github.com/apache/drill/pull/1226#discussion_r183768380
--- Diff: exec/java-exec/src/test/java/org/apache/drill/TestUnionAll.java
---
@@ -634,10 +634,14 @@ public void testFilterPushDownOverUnionAll() throws
Exception {
+ "order by n_regionkey";
// Validate the plan
- final String[] expectedPlan = {".*Filter.*\n" +
- ".*UnionAll.*\n" +
- ".*Scan.*columns=\\[`n_regionkey`\\].*\n" +
- ".*Scan.*columns=\\[`r_regionkey`\\].*"};
+ final String[] expectedPlan = {"Sort.*\n" +
--- End diff --
Looks like there are no issues related to it. I have added additional test
case to verify it:
`select n_nationkey from (select n_nationkey, n_name, n_comment from
cp."tpch/nation.parquet" union all select r_regionkey, r_name, r_comment from
cp."tpch/region.parquet") where n_nationkey > 4;`
When filter is pushed down the result from right side of UNION will be
empty.
Generally speaking using UNION operator with empty data was resolved in
[DRILL-4185](https://issues.apache.org/jira/browse/DRILL-4185) and we have test
cases with empty data batches.
---
