kasakrisz opened a new pull request, #4637:
URL: https://github.com/apache/hive/pull/4637
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### What changes were proposed in this pull request?
Disable removing zero row producing query plan optimization when the schema
contains any complex types. More precisely we fall back to convert the plan to
a `HiveSortLimit(fetch=0, input=<sub plan producing 0 rows>)`. This was the
original representation of Empty operator before this optimization was
introduced.
### Why are the changes needed?
The Calcite plan is converted back to AST in ASTConverter before going to
Hive operator plan. AST does not contain type information and a `NULL` value
having complex type can not be accurately represented.
This makes impossible of running CTAS statements when the select clause does
not produces any rows because the schema of the new table can not be inferred.
### Does this PR introduce _any_ user-facing change?
No.
### Is the change a dependency upgrade?
No.
### How was this patch tested?
```
mvn test -Dtest.output.overwrite -DskipSparkTests
-Dtest=TestMiniLlapLocalCliDriver -Dqfile=empty_result_ctas.q -pl itests/qtest
-Pitests
```
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