postgres-xc-developers Mailing List for Postgres-XC

Thanks Ashutosh for the reply.

---
Koichi Suzuki

2015-05-15 16:13 GMT+09:00 Ashutosh Bapat <ash...@en...>:

>
>
> On Fri, May 15, 2015 at 12:13 PM, Manikandan Soundarapandian <
> ma...@vt...> wrote:
>
>> Hi,
>>
>> Am trying to understand how the coordinator node collects query results
>> from the datanodes. I see the method handle_response()
>> in ../backend/pgxc/pool/execRemote.c is called for every connection
>> handle. In an infinite for loop, it collects messages from the data
>> nodes and combines the results. I am confused between the two case
>> statements 'D' and 'd'. What is the difference between these two cases?
>> What exactly is the difference between the methods 'HandleDataRow' and
>> 'HandleCopyDataRow' and can you give an example when each of these
>> methods are invoked? Please help. This will help in my research work.
>>
>>
> I guess HandleDataRow handles "data" row of a query result. The other
> function handles the output of COPY command. These two have different forms.
>
>
>> Thanks
>> Mani
>>
>>
>>
>> ------------------------------------------------------------------------------
>> One dashboard for servers and applications across Physical-Virtual-Cloud
>> Widest out-of-the-box monitoring support with 50+ applications
>> Performance metrics, stats and reports that give you Actionable Insights
>> Deep dive visibility with transaction tracing using APM Insight.
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>> _______________________________________________
>> Postgres-xc-developers mailing list
>> Pos...@li...
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>>
>
>
>
> --
> Best Wishes,
> Ashutosh Bapat
> EnterpriseDB Corporation
> The Postgres Database Company
>
>
> ------------------------------------------------------------------------------
> One dashboard for servers and applications across Physical-Virtual-Cloud
> Widest out-of-the-box monitoring support with 50+ applications
> Performance metrics, stats and reports that give you Actionable Insights
> Deep dive visibility with transaction tracing using APM Insight.
> http://ad.doubleclick.net/ddm/clk/290420510;117567292;y
> _______________________________________________
> Postgres-xc-developers mailing list
> Pos...@li...
> https://lists.sourceforge.net/lists/listinfo/postgres-xc-developers
>
>

Hi Ashutosh,

Thanks for the reply. Do you mean the COPY command like the following
that we use to copy query result to a file,

COPY (select * from xxx) to '/home/xx.txt'

Thanks
Mani

On Fri, 2015-05-15 at 12:43 +0530, Ashutosh Bapat wrote:
> 
> 
> On Fri, May 15, 2015 at 12:13 PM, Manikandan Soundarapandian
> <ma...@vt...> wrote:
>         Hi,
>         
>         Am trying to understand how the coordinator node collects
>         query results
>         from the datanodes. I see the method handle_response()
>         in ../backend/pgxc/pool/execRemote.c is called for every
>         connection
>         handle. In an infinite for loop, it collects messages from the
>         data
>         nodes and combines the results. I am confused between the two
>         case
>         statements 'D' and 'd'. What is the difference between these
>         two cases?
>         What exactly is the difference between the methods
>         'HandleDataRow' and
>         'HandleCopyDataRow' and can you give an example when each of
>         these
>         methods are invoked? Please help. This will help in my
>         research work.
>         
> 
> 
> I guess HandleDataRow handles "data" row of a query result. The other
> function handles the output of COPY command. These two have different
> forms.
> 
>  
>         Thanks
>         Mani
>         
>         
>         ------------------------------------------------------------------------------
>         One dashboard for servers and applications across
>         Physical-Virtual-Cloud
>         Widest out-of-the-box monitoring support with 50+ applications
>         Performance metrics, stats and reports that give you
>         Actionable Insights
>         Deep dive visibility with transaction tracing using APM
>         Insight.
>         http://ad.doubleclick.net/ddm/clk/290420510;117567292;y
>         _______________________________________________
>         Postgres-xc-developers mailing list
>         Pos...@li...
>         https://lists.sourceforge.net/lists/listinfo/postgres-xc-developers
> 
> 
> 
> -- 
> Best Wishes,
> Ashutosh Bapat
> EnterpriseDB Corporation
> The Postgres Database Company
> 

On Fri, May 15, 2015 at 12:13 PM, Manikandan Soundarapandian <ma...@vt...>
wrote:

> Hi,
>
> Am trying to understand how the coordinator node collects query results
> from the datanodes. I see the method handle_response()
> in ../backend/pgxc/pool/execRemote.c is called for every connection
> handle. In an infinite for loop, it collects messages from the data
> nodes and combines the results. I am confused between the two case
> statements 'D' and 'd'. What is the difference between these two cases?
> What exactly is the difference between the methods 'HandleDataRow' and
> 'HandleCopyDataRow' and can you give an example when each of these
> methods are invoked? Please help. This will help in my research work.
>
>
I guess HandleDataRow handles "data" row of a query result. The other
function handles the output of COPY command. These two have different forms.


> Thanks
> Mani
>
>
>
> ------------------------------------------------------------------------------
> One dashboard for servers and applications across Physical-Virtual-Cloud
> Widest out-of-the-box monitoring support with 50+ applications
> Performance metrics, stats and reports that give you Actionable Insights
> Deep dive visibility with transaction tracing using APM Insight.
> http://ad.doubleclick.net/ddm/clk/290420510;117567292;y
> _______________________________________________
> Postgres-xc-developers mailing list
> Pos...@li...
> https://lists.sourceforge.net/lists/listinfo/postgres-xc-developers
>



-- 
Best Wishes,
Ashutosh Bapat
EnterpriseDB Corporation
The Postgres Database Company

Hi,

Am trying to understand how the coordinator node collects query results
from the datanodes. I see the method handle_response()
in ../backend/pgxc/pool/execRemote.c is called for every connection
handle. In an infinite for loop, it collects messages from the data
nodes and combines the results. I am confused between the two case
statements 'D' and 'd'. What is the difference between these two cases?
What exactly is the difference between the methods 'HandleDataRow' and
'HandleCopyDataRow' and can you give an example when each of these
methods are invoked? Please help. This will help in my research work.

Thanks
Mani