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https://issues.apache.org/jira/browse/IGNITE-14544?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17344522#comment-17344522
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Taras Ledkov edited comment on IGNITE-14544 at 5/14/21, 10:45 AM:
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[~agoncharuk], great comment!
I guess we have to use {{AggregateExpandDistinctAggregatesRule.Config.JOIN}}
rule because it make sense when there is several indexes for all (some)
groups. Performance boost or memory usage reduce is expected in this case.
Looks like expand distinct aggregates to several groupSets inside one agg node
doesn't make sense because it is similar to HashAggregation with distinct
accumulators (from current patch). BUT distinct accumulators allow to use
SortAggregation (several groups in {{groupSets}} doesn't allow to use sort
aggregation).
What do you think about?
was (Author: tledkov-gridgain):
[~agoncharuk], great comment!
I guess we have to use {{AggregateExpandDistinctAggregatesRule.Config.JOIN}}
rule because it make sense when there is several indexes for all (some)
groups. Performance boost or memory usage reduce is expected in this case.
Looks like expand distinct aggregates to several groupSets inside one agg node
doesn't make sense because it is similar to HashAggregation with distinct
accumulators (from current patch). BUT distinct accumulators allow to use
SortAggregation (several groups in {{groupSets}} doesn't allow to use sort
aggregation).
> Calcite engine. Support DISTINCT aggregates
> -------------------------------------------
>
> Key: IGNITE-14544
> URL: https://issues.apache.org/jira/browse/IGNITE-14544
> Project: Ignite
> Issue Type: Bug
> Reporter: Taras Ledkov
> Assignee: Taras Ledkov
> Priority: Major
> Time Spent: 10m
> Remaining Estimate: 0h
>
> Now, DISTINCT aggregates not implemented.
> (e.g. {{SELECT COUNT (DISTINCT lastName) FROM person}})
> Tests:
> {{aggregate/aggregates/test_count.test}}
> {{aggregate/aggregates/test_avg.test}}
> {{aggregate/aggregates/test_distinct_aggr.test}}
> {{aggregate/aggregates/test_distinct_string_agg.test}}
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