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From Dmitriy Setrakyan <dsetrak...@apache.org>
Subject Re: min()/max() SQL and indexes
Date Wed, 04 Jan 2017 16:37:35 GMT
Is there a ticket for this issue?

On Wed, Jan 4, 2017 at 3:11 AM, Sergi Vladykin <sergi.vladykin@gmail.com>
wrote:

> Our indexes do not support this optimization right now.
>
> It is not that hard to implement it, I'd suggest to plan it for
> 2.0+PageMemory, because otherwise we'll have to implement it twice with
> conflicts.
>
> Sergi
>
>
>
> 2017-01-03 22:59 GMT+03:00 Valentin Kulichenko <
> valentin.kulichenko@gmail.com>:
>
> > Folks,
> >
> > Does anyone know if index is supposed to be used when a query like below
> > is executed?
> >
> > select min(id) from MyValue
> > select max(id) from MyValue
> >
> > I tried it and execution time doesn't seem to depend on whether I create
> > an index for 'id' field or not. It always takes around 2 seconds with
> only
> > 5,000,000 records on a single node. Result is the same for min() and
> max(),
> > so index order doesn't seem to have affect either.
> >
> > Execution plan shows that index is used though:
> >
> > SELECT
> >     MAX(ID) AS __C0
> > FROM "test".MYVALUE
> >     /* "test"."id_idx" */
> >
> > SELECT
> >     MAX(__C0) AS __C0
> > FROM PUBLIC.__T0
> >     /* "test"."merge_scan" */
> >
> > Sergi, can you please clarify what is the expected behavior here?
> >
> > -Val
> >
>

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