Re: Do parallel queries work with only dblink not with fdw?

>From: pgsql-general-owner@postgresql.org [mailto:pgsql-general-owner@postgresql.org] On Behalf Of Klaus P.
>Sent: Mittwoch, 4. Mai 2016 10:28
>To: pgsql-general@postgresql.org
>Subject: [GENERAL] Do parallel queries work with only dblink not with fdw?
>
>In order to improve cpu and disk utilization, I am testing parallel queries. 
>
>The approach with dblink_send_query() and dblink_get_result() works in my proof-of-concept. Runtime of my reference
querywas reduced from 55 seconds to ~20seconds using 4 parallel connections. Not what I had hoped but certainly a
significantimprovement.
 
>My approach is fairly easy: 
>db_link_send_query('conn1', 'statement based on partitioning field');
>db_link_send_query('conn2', 'statement based on partitioning field');
>
>...
>SELECT 
>dblink_get_result('conn1')
>UNION ALL 
>dblink_get_result('conn2')
>
>...


Hello,

I'm using the db_link approach too, but rather than using dblink_get_result, I store the result in an additional
table.
This was faster, at least for my use case and at the time when I implemented that solution...

something like 

db_link_send_query('conn0', 'CREATE UNLOGGED TABLE  my_result...
db_link_send_query('conn1', 'INSERT INTO my_result  statement based on partitioning field');
db_link_send_query('conn2', 'INSERT INTO my_result  statement based on partitioning field');
...
select * from my_result

regards,

Marc Mamin