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https://issues.apache.org/jira/browse/CALCITE-2997?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17106592#comment-17106592
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Steven Talbot commented on CALCITE-2997:
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cc [~julianhyde]
I'd move to reopen this. Even if the original case perhaps does not need to
turn this off, I think there are valid cases where we would want to add a
config parameter to disable this behavior. While the push down provides a more
optimized plan, it also creates a more complex tree of RelNodes and writes much
more verbose SQL if those RelNodes are translated back to SQL with the Projects
that this rule creates. I could see a variety of cases where one would prefer
for those reasons to disable this behavior.
> 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
> Priority: Major
>
> 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(A)
> |-Project(x * 2 as col1)
> |-Scan(B){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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