jin xing created CALCITE-2997:
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Summary: Avoid pushing down join condition in SqlToRelConverter
Key: CALCITE-2997
URL: https://issues.apache.org/jira/browse/CALCITE-2997
Project: Calcite
Issue Type: Bug
Reporter: jin xing
In current code, *SqlToRelConverter:createJoin* is calling
*RelOptUtil.pushDownJoinConditions* for optimization. And we can find below
conversion from *SqlNode* to *RelNode*:
{code:java}
SqlNode:
select * from A join B on A.x = B.x * 2
RelNode (Logical-Plan):
Join (condition:col0=col1)
|-Project(x as col0)
| |-Scan
|-Project(x * 2 as col1)
|-Scan{code}
As we can see the logical plan(*RelNode*) posted above is not the pure
reflection of the original SQL String(*SqlNode*). The optimization is mixed
into the phase on which AST is converted to Logical-Plan. Actually optimizing
rule of JoinPushExpressionsRule is doing exactly the same kind of thing. Shall
we just keep the optimization inside Optimized-Logical-Plan ? I mean shall we
avoid calling *RelOptUtil.pushDownJoinConditions* in
*SqlToRelConverter:createJoin*
I raised this issue because that we are doing something based on the
Logical-Plan. And it makes us really confused that the Logical-Plan doesn't
corresponds to SqlNode.
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