[CALCITE-3182] Trim unused fields for plan of materialized-view before matching.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.21.0
• Labels: pull-request-available
• Assignee: Unassigned
• Reporter: Jin Xing
• Created: 08/Jul/19 12:05
• Updated: 10/Sep/19 21:36
• Resolved: 19/Jul/19 07:13

Description

In current code, before matching query with materialized-view, unused fields of query is trimmed but materialized-view is not. Thus below simple SQL fails to be matched though query and materialized-
view are exactly the same:

@Test public void testMaterializationAfterTrimingOfUnusedFields() {
String sql =
"select \"y\".\"deptno\", \"y\".\"name\", \"x\".\"sum_salary\"\n" +
"from\n" +
" (select \"deptno\", sum(\"salary\") \"sum_salary\" from \"emps\" group by \"deptno\") \"x\"\n" +
" join\n" +
" \"depts\" \"y\"\n" +
" on \"x\".\"deptno\"=\"y\".\"deptno\"\n";
checkMaterialize(sql, sql);
}

 Checking CalciteMaterializer https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/prepare/CalciteMaterializer.java#L83 , I think the code intends to do the trimming, but didn't call the method.
Since unused fields of query is trimmed anyway https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/prepare/CalcitePrepareImpl.java#L995 , thus I think there's no necessity to keep the materialized-view un-trimmed

Issue Links

• is related to: CALCITE-3113 Equivalent MutableAggregates with different row types fail with AssertionError
• links to: GitHub Pull Request #1307