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https://issues.apache.org/jira/browse/IGNITE-20383?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Yury Gerzhedovich updated IGNITE-20383:
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Labels: calcite calcite2-required calcite3-required ise (was: calcite
calcite3-required ise)
> Calcite engine. Convert one input of a join to the broadcast distribution
> -------------------------------------------------------------------------
>
> Key: IGNITE-20383
> URL: https://issues.apache.org/jira/browse/IGNITE-20383
> Project: Ignite
> Issue Type: Improvement
> Reporter: Aleksey Plekhanov
> Assignee: Aleksey Plekhanov
> Priority: Major
> Labels: calcite, calcite2-required, calcite3-required, ise
>
> Sometimes, if join inputs are not collocated it's worth to broadcast one of
> the inputs, for example, query:
> {code:sql}
> SELECT * FROM emps WHERE emps.salary = (SELECT AVG(emps.salary) FROM
> emps){code}
> Currently has plan:
> {noformat}
> IgniteProject(ID=[$0], NAME=[$1], SALARY=[$2])
> IgniteNestedLoopJoin(condition=[=($2, $3)], joinType=[inner])
> IgniteExchange(distribution=[single])
> IgniteTableScan(table=[[PUBLIC, EMPS]])
> IgniteReduceHashAggregate(group=[{}], AVG(EMPS.SALARY)=[AVG($0)])
> IgniteExchange(distribution=[single])
> IgniteMapHashAggregate(group=[{}], AVG(EMPS.SALARY)=[AVG($0)])
> IgniteIndexScan(table=[[PUBLIC, EMPS]], index=[TST],
> requiredColumns=[{2}], collation=[[2 ASC-nulls-first]])
> {noformat}
> But this plan is not optimal, since we should send entire table EMP from all
> nodes to the single node. For such a query it's better to broadcast result of
> the aggregation, in this case plan will be something like:
> {noformat}
> IgniteExchange(distribution=[single])
> IgniteProject(...)
> IgniteCorrelatedNestedLoopJoin(...)
> IgniteExchange(distribution=[broadcast])
> IgniteReduceHashAggregate(group=[{}], AVG(EMPS.SALARY)=[AVG($0)])
> IgniteExchange(distribution=[single])
> IgniteMapHashAggregate(group=[{}], AVG(EMPS.SALARY)=[AVG($0)])
> IgniteIndexScan(table=[[PUBLIC, EMPS]], index=[SALARY_IDX])
> IgniteIndexScan(table=[[PUBLIC, EMPS]], index=[SALARY_IDX])
> {noformat}
> But currently we don't try to convert any of the join inputs to the broadcast
> distribution. We should try to do this.
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