Union All View execution

Started by Ivan Novickabout 10 years ago2 messages
#1Ivan Novick
inovick@pivotal.io

Hi,

If we have two queries, Query A and Query B that both return same columns.

If we do Union All View will postgresql execute Query A and then Query B
sequentially?

Does the work being discussed around parallel query have the potential to
parallely execute both parts of a Union All View?

Also is there a pointer to the latest summary of goals and design for
parallel query work?

Thanks!

Cheers,
Ivan

#2Amit Kapila
amit.kapila16@gmail.com
In reply to: Ivan Novick (#1)
Re: Union All View execution

On Thu, Oct 15, 2015 at 11:33 AM, Ivan Novick <inovick@pivotal.io> wrote:

Hi,

If we have two queries, Query A and Query B that both return same columns.

If we do Union All View will postgresql execute Query A and then Query B
sequentially?

Does the work being discussed around parallel query have the potential to
parallely execute both parts of a Union All View?

The work being currently done will not cover this case. However,
each individual Query's involved in union could be run in parallel, if
they meet criterial for parallel query (like doesn't use parallel-unsafe
clauses).

With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com