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From Guillermo Ortiz <konstt2...@gmail.com>
Subject Re: GroupBy with index is really slow.
Date Wed, 10 May 2017 14:56:47 GMT
It's my laptop. 16gb, i7.. The collection size it's 5Mill objects (1,2GB)
and it takes about 30sec.
I have tried to execute the query with the same collection with and without
indices with the same time results.

This is a test before to run in the real cluster with 6 nodes of 512Gb and
48cores each one. We tried to execute there with a real dataset(22M rows,
7gb) but it takes so long that query is aborted.


2017-05-08 12:12 GMT+02:00 Andrey Mashenkov <andrey.mashenkov@gmail.com>:

> Hi,
>
> Why do you think query is slow?
> What its execution time? What is expected time?
> How many nodes do you use? How much data does cache contains?
>
> On Mon, May 8, 2017 at 1:47 AM, Guillermo Ortiz <konstt2000@gmail.com>
> wrote:
>
>> I have a simple cache where I have Person object (id, age and so on..)
>>
>> I have created indeces by id and age to try some examples but queries
>> with "group by" go really slow.
>>
>> I'm trying this query:
>> SELECT age
>> FROM
>> PersonWithindex
>> group by age
>>
>>
>> SELECT
>>     AGE AS __C0
>> FROM "personCacheWithIndex".PERSONWITHINDEX
>>     /* "personCacheWithIndex"."age_idx" */
>> GROUP BY AGE
>> /* group sorted */
>>
>> SELECT
>>     __C0 AS AGE
>> FROM PUBLIC.__T0
>>     /* "personCacheWithIndex"."merge_scan" */
>> GROUP BY __C0
>>
>> Although it seems that it uses index, why is it going so slow? I think
>> that it should be pretty fast with an index.
>>
>
>
>
> --
> Best regards,
> Andrey V. Mashenkov
>

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