Re: [Postgres-xc-developers] Understanding how coordinator collects data from datanodes

[Ashutosh B. <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
>
>
>
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-- 
Best Wishes,
Ashutosh Bapat
EnterpriseDB Corporation
The Postgres Database Company