Re: [Postgres-xc-developers] Manually Table Partitioning

[Michael P. <mic...@gm...>]

On Fri, Mar 29, 2013 at 7:19 PM, Kaiji Chen <ch...@im...> wrote:

>  Hi,
> I'm working on a data partitioning project on PostgreSQL by adding a
> middleware between the database cluster interface and applications that
> modify the SQL statement to specific data nodes. I just find that
> PostgresXC has a nice GTM that can help me do the distributed transaction
> management works, I considered to transfer my project on it.
> It seems the sliders (
> http://wiki.postgresql.org/images/f/f6/PGXC_Scalability_PGOpen2012.pdf)
> intend that user defined table distribution is not available, but the
> coordinator can choose specific data node when processing the queries, and
> the table will be distributed to by default if DISTRIBUTED BY is not
> specified. Then I wonder if I can specify a data node in each query and
> stop the default auto distributing process.
>
For SELECT queries, you can use EXECUTE DIRECT:
http://postgres-xc.sourceforge.net/docs/1_0_2/sql-executedirect.html
The results you get might not be exact as not global query planning is not
done and the query string is sent as-is.

Note that you cannot use EXECUTE DIRECT with DML or the whole cluster
consistency would be broken.
--
Michael