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From Denis Magda <dma...@apache.org>
Subject Re: SQL query collocated flag
Date Tue, 10 Jan 2017 20:04:37 GMT
Sergi,

What does ‘more effective query plan’ exactly means? Will the aggregation happen on the
data nodes and why this flag set to ‘true’ leads to strange behavior described here [1]
which sounds like a bug?

As for the documentation how would you rewrite existed setCollocated explanation [2] so that
it becomes clearer what the flag is for and how it works? Please provide your doc version.

[1] http://apache-ignite-users.70518.x6.nabble.com/NOT-IN-in-ignite-td9861.html
[2] https://apacheignite.readme.io/docs/configuration-parameters#section--sqlfields-and-sqlfieldsquery-configuration-properties
<https://apacheignite.readme.io/docs/configuration-parameters#section--sqlfields-and-sqlfieldsquery-configuration-properties>

—
Denis

> On Jan 10, 2017, at 9:13 AM, Sergi Vladykin <sergi.vladykin@gmail.com> wrote:
> 
> Yes, this flag indeed is very obscure. Basically it means that if you have
> some query with aggregates (at the top level right now) and you know that
> you will do GROUP BY by affinity key, then Ignite can generate a more
> effective query plan with this flag set.
> 
> Sergi
> 
> 2017-01-10 2:22 GMT+03:00 Valentin Kulichenko <valentin.kulichenko@gmail.com
>> :
> 
>> Folks,
>> 
>> One of the users faced an interesting case [1]. Basically, there is a
>> query [2] which returns correct result when collocated flag is not set, but
>> if it's true, several counts for each node is received by the client
>> without being aggregated. Is this expected? I'm also attaching the test
>> that reproduces behavior.
>> 
>> Actually, the flag seems to be very confusing and documentation
>> description [3] doesn't help a lot. I'm reading it and it's not clear what
>> has to be collocated, what would happen if I incorrectly set the flag to
>> true, etc. Probably, some examples could help. Can someone elaborate?
>> 
>> [1] http://apache-ignite-users.70518.x6.nabble.com/NOT-
>> IN-in-ignite-td9861.html
>> [2] SELECT count(*) as COUNT FROM Person p join table(joinId VARCHAR(50) =
>> ?) i on p.id = i.joinId
>> [3] https://apacheignite.readme.io/docs/configuration-
>> parameters#section--sqlfields-and-sqlfieldsquery-configuration-properties
>> 
>> -Val
>> 


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