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https://issues.apache.org/jira/browse/CALCITE-5784?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17733908#comment-17733908
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Aitozi commented on CALCITE-5784:
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We can also try to avoid process toRel for the {{SqlWithItem}} only when it is
first referenced. In this way, we can generate only one RelNode instance for
one SqlWithItem and the correlation will be generated once.
Do you think it's feasible/reasonable ? [~libenchao]
> Generate the same correlationId for the same query
> --------------------------------------------------
>
> Key: CALCITE-5784
> URL: https://issues.apache.org/jira/browse/CALCITE-5784
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Reporter: Aitozi
> Priority: Major
> Labels: pull-request-available
>
> Currently, the CTE query block will be sql2rel multiple times if be
> referenced multiple times. If it contains a lateral join, it will generate
> different correlation id. See below:
> {code:java}
> String sql = "WITH a AS (SELECT ename, job, empno, r FROM emp, LATERAL
> TABLE (ramp(empno)) as T(r))"
> + " SELECT * from a a1, a a2 WHERE a1.r = a2.empno";
> sql(sql).ok();
> {code}
> {code:java}
> LogicalProject(ENAME=[$0], JOB=[$1], EMPNO=[$2], R=[$3], ENAME0=[$4],
> JOB0=[$5], EMPNO0=[$6], R0=[$7])
> LogicalJoin(condition=[=($3, $6)], joinType=[inner])
> LogicalProject(ENAME=[$1], JOB=[$2], EMPNO=[$0], R=[$9])
> LogicalCorrelate(correlation=[$cor0], joinType=[inner],
> requiredColumns=[{0}])
> LogicalTableScan(table=[[CATALOG, SALES, EMP]])
> LogicalTableFunctionScan(invocation=[RAMP($cor0.EMPNO)],
> rowType=[RecordType(INTEGER I)])
> LogicalProject(ENAME=[$1], JOB=[$2], EMPNO=[$0], R=[$9])
> LogicalCorrelate(correlation=[$cor1], joinType=[inner],
> requiredColumns=[{0}])
> LogicalTableScan(table=[[CATALOG, SALES, EMP]])
> LogicalTableFunctionScan(invocation=[RAMP($cor1.EMPNO)],
> rowType=[RecordType(INTEGER I)])
> {code}
> It will generate two correlation id. In flink there is a subplan reuse based
> on the digest, the same query produce diff digest will break this
> functionality
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