[jira] [Commented] (CALCITE-7024) Decorrelator does not always produce a query with the same type signature

["suibianwanwan (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-7024?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17952323#comment-17952323 ] 

suibianwanwan commented on CALCITE-7024:
----------------------------------------

I speculate the reason is: In `decorrelateRel`, when we rewrite the query as a Join, we add a `corVar` column for subsequent Joins. I noticed that in `decorrelateRel(Correlate)`, we didn't add a Project to eliminate this `corVar` (since this column might still be needed for eliminating other Correlate).

> Decorrelator does not always produce a query with the same type signature
> -------------------------------------------------------------------------
>
>                 Key: CALCITE-7024
>                 URL: https://issues.apache.org/jira/browse/CALCITE-7024
>             Project: Calcite
>          Issue Type: Bug
>          Components: core
>    Affects Versions: 1.39.0
>            Reporter: Mihai Budiu
>            Priority: Minor
>
> While trying to implement  [CALCITE-7023] I stumbled on some examples for which the query produced by the decorrelator has a different type signature from the input query. I think this should be impossible.
> Original plan:
> {code}
> LogicalCorrelate(correlation=[$cor0], joinType=[left], requiredColumns=[{0}]), id = 161
>   LogicalTableScan(table=[[schema, s]]), id = 95
>   LogicalSort(fetch=[1]), id = 159
>     LogicalAggregate(group=[{}], EXPR$0=[SUM($0)]), id = 157
>       LogicalProject(x=[$0]), id = 155
>         LogicalFilter(condition=[=($cor0.y, $1)]), id = 153
>           LogicalTableScan(table=[[schema, t]]), id = 97
> {code}
> Error produced when attempting to replace this plan after decorrelating it:
> {code}
> set type is RecordType(INTEGER y, DECIMAL(28, 2) EXPR$0) NOT NULL
> expression type is RecordType(INTEGER y, DECIMAL(28, 2) EXPR$0, INTEGER z) NOT NULL
> set is rel#161:LogicalCorrelate.(left=HepRelVertex#151,right=HepRelVertex#160,correlation=$cor0,joinType=left,requiredColumns={0})
> expression is LogicalJoin(condition=[=($0, $2)], joinType=[left])
>   LogicalTableScan(table=[[schema, s]])
>   LogicalProject(EXPR$0=[FIRST_VALUE($1) OVER (PARTITION BY $0)], z=[$0])
>     LogicalAggregate(group=[{0}], EXPR$0=[SUM($1)])
>       LogicalProject(z=[$1], x=[$0])
>         LogicalFilter(condition=[IS NOT NULL($1)])
>           LogicalTableScan(table=[[schema, t]])
> Type mismatch: the field sizes are not equal.
> rowtype of original rel: RecordType(INTEGER y, DECIMAL(28, 2) EXPR$0) NOT NULL
> rowtype of new rel: RecordType(INTEGER y, DECIMAL(28, 2) EXPR$0, INTEGER z) NOT NULL
> {code}



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