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https://issues.apache.org/jira/browse/IGNITE-21948?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Andrey Mashenkov reassigned IGNITE-21948:
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Assignee: Andrey Mashenkov
> Rethink distributed aggregates converter rules.
> -----------------------------------------------
>
> Key: IGNITE-21948
> URL: https://issues.apache.org/jira/browse/IGNITE-21948
> Project: Ignite
> Issue Type: Improvement
> Components: sql
> Reporter: Andrey Mashenkov
> Assignee: Andrey Mashenkov
> Priority: Major
> Labels: ignite-3, perfomance, sql
>
> *Motivation.*
> We convert LogicalAggregate to map-reduce unconditionally (if possible),
> which blows plan search space.
> Some plans, which have reduce-phase followed by map-phase without Exchange,
> make no sense and will be thrown away after applying cost model (if no -
> there is a bug).
> *Suggestion.*
> What if we will emit only plans with colocated aggregates?
> We can write rules to pushdown colocated aggregate through Exchange via
> splitting into map-reduce phases, if colocation can't be preserved.
> If Exchange can preserve colocation, then aggregate is pushed gown without
> splitting.
> Let's investigate, if we can eliminate (or significantly decrease number of
> plans)
> # with Exchange-less Reduce->Map
> # map-reduce aggregates on colocated data.
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