[jira] [Assigned] (IGNITE-21580) Sql. Unable to optimise query using only two phase aggregates

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

     [ https://issues.apache.org/jira/browse/IGNITE-21580?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Andrey Mashenkov reassigned IGNITE-21580:
-----------------------------------------

    Assignee: Andrey Mashenkov  (was: Maksim Zhuravkov)

> Sql. Unable to optimise query using only two phase aggregates
> -------------------------------------------------------------
>
>                 Key: IGNITE-21580
>                 URL: https://issues.apache.org/jira/browse/IGNITE-21580
>             Project: Ignite
>          Issue Type: Bug
>          Components: sql
>            Reporter: Konstantin Orlov
>            Assignee: Andrey Mashenkov
>            Priority: Major
>              Labels: ignite-3
>
> As for now, query planner returns following plan for q1 from TPC H suite:
> {code:java}
> IgniteColocatedSortAggregate
>   IgniteExchange(distribution=[single])
>     IgniteSort
>       IgniteIndexScan(index=[L_SD], searchBounds=[[RangeBounds [lowerBound=null, upperBound=-(1998-12-01, 7776000000:INTERVAL DAY), lowerInclude=true, upperInclude=true]]])
> {code}
> The first problem is it's not even optimal variant from possible ones. By simply excluding {{SortAggregateConverterRule.COLOCATED}} from planning phase, we will get plan as follow:
> {code:java}
> IgniteSort
>   IgniteColocatedHashAggregate
>     IgniteExchange(distribution=[single])
>       IgniteIndexScan(index=[L_SD], searchBounds=[[RangeBounds [lowerBound=null, upperBound=-(1998-12-01, 7776000000:INTERVAL DAY), lowerInclude=true, upperInclude=true]]])
> {code}
> Latter plan is executed ~40% faster than the first one.
> Seems, it's possible to reduce time even further by taking an advantage of two-phase aggregates, but disabling both version of colocated aggregates results in an exception during planning phase.
> Within this ticket, let's address the issue preventing optimiser from usage of two-phase aggregates, and also tweak cost function to make optimiser choose better plan.



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