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From Denis Magda <dma...@apache.org>
Subject Re: min()/max() SQL and indexes
Date Wed, 04 Jan 2017 18:21:33 GMT
https://issues.apache.org/jira/browse/IGNITE-4524 <https://issues.apache.org/jira/browse/IGNITE-4524>

Put it for 2.0. Sergi, assigned the ticket on you so that you can provide implementations
details or take care of it personally. Whatever you prefer.

—
Denis

> On Jan 4, 2017, at 8:37 AM, Dmitriy Setrakyan <dsetrakyan@apache.org> wrote:
> 
> 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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