Arina Ielchiieva created DRILL-5538:
---------------------------------------
Summary: Exclude ProjectRemoveRule during PHYSICAL phase if it
comes from storage plugins
Key: DRILL-5538
URL: https://issues.apache.org/jira/browse/DRILL-5538
Project: Apache Drill
Issue Type: Bug
Components: Query Planning & Optimization
Affects Versions: 1.10.0
Reporter: Arina Ielchiieva
Assignee: Arina Ielchiieva
When [RDBMS storage plugin|https://drill.apache.org/docs/rdbms-storage-plugin/]
is enabled, during query execution certain JDBC rules are added.
One of the rules is
[ProjectRemoveRule|https://github.com/apache/drill/blob/master/contrib/storage-jdbc/src/main/java/org/apache/drill/exec/store/jdbc/JdbcStoragePlugin.java#L140].
Drill also uses this rule but during phases when it considers it useful, for
example, during LOGICAL and JOIN_PLANNING. On the contrary, storage plugin
rules are added to any phase of query planning. Thus it results to project
stage to be removed when actually it is needed.
Sometimes when ProjectRemoveRule decides that project is trivial and removes
it, during this stage Drill added column alias or removed implicit columns.
For example, with RDBMS plugin enabled, alias is not displayed for simple query:
{noformat}
0: jdbc:drill:zk=local> create temporary table t as select * from sys.version;
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further
details.
+-----------+----------------------------+
| Fragment | Number of records written |
+-----------+----------------------------+
| 0_0 | 1 |
+-----------+----------------------------+
1 row selected (0.623 seconds)
0: jdbc:drill:zk=local> select version as current_version from t;
+------------------+
| version |
+------------------+
| 1.11.0-SNAPSHOT |
+------------------+
1 row selected (0.28 seconds)
{noformat}
Proposed fix is to exclude ProjectRemoveRule during PHYSICAL phase if it comes
from storage plugins to prevent Drill losing column alias or displaying
implicit columns.
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