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https://issues.apache.org/jira/browse/DRILL-5851?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16285109#comment-16285109
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ASF GitHub Bot commented on DRILL-5851:
---------------------------------------
Github user paul-rogers commented on a diff in the pull request:
https://github.com/apache/drill/pull/1059#discussion_r155939506
--- Diff:
exec/java-exec/src/test/java/org/apache/drill/exec/physical/unit/TestNullInputMiniPlan.java
---
@@ -323,8 +323,6 @@ public void testHashJoinLeftEmpty() throws Exception {
.build();
BatchSchema expectedSchema = new SchemaBuilder()
- .addNullable("a", TypeProtos.MinorType.BIGINT)
- .addNullable("b", TypeProtos.MinorType.BIGINT)
--- End diff --
I wonder about this. This test came out of the "empty batches" project
which attempted to handle empty inputs. If this PR finds the need to change the
tests, then we are changing semantics of how we handle schemas. Are we sure we
want to make this change?
If we are changing the schema, are we saying that if we get no left input
(but do get a schema), that we won't product the joined schema? This would seem
to be a bug rather than a feature.
> Empty table during a join operation with a non empty table produces cast
> exception
> -----------------------------------------------------------------------------------
>
> Key: DRILL-5851
> URL: https://issues.apache.org/jira/browse/DRILL-5851
> Project: Apache Drill
> Issue Type: Bug
> Components: Execution - Relational Operators
> Affects Versions: 1.11.0
> Reporter: Hanumath Rao Maduri
> Assignee: Hanumath Rao Maduri
>
> Hash Join operation on tables with one table empty and the other non empty
> throws an exception
> {code}
> Error: SYSTEM ERROR: DrillRuntimeException: Join only supports implicit casts
> between 1. Numeric data
> 2. Varchar, Varbinary data 3. Date, Timestamp data Left type: VARCHAR, Right
> type: INT. Add explicit casts to avoid this error
> {code}
> Here is an example query with which it is reproducible.
> {code}
> select * from cp.`sample-data/nation.parquet` nation left outer join
> dfs.tmp.`2.csv` as two on two.a = nation.`N_COMMENT`;
> {code}
> the contents of 2.csv is empty (i.e not even header info).
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