Re: [HACKERS] PATCH: enabling parallel execution for cursorsexplicitly (experimental)

On 2 November 2017 at 10:01, Robert Haas <robertmhaas@gmail.com> wrote:

> I think that still leaves a fair number of scenarios to consider, and
> the error handling by itself seems pretty thorny.  Plus it's kind of a
> weird mode and, like Craig, I'm not really sure what it gets you.
> Maybe if somebody has the use case where this would help, they should
> just do:
>
> CREATE TEMP TABLE x AS SELECT * FROM t2 WHERE ...;
> DECLARE x CURSOR FOR SELECT * FROM x;

That forces materialization, and I'm guessing part of Tomas's goal
here is to prevent the need to materialize into a temp table /
tuplestore / etc.

It's not clear to me why an unbounded portal fetch, using the tcp
socket windows and buffers for flow control, isn't sufficient.

Tomas, can you explain the use case a bit more?


-- Craig Ringer                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services


-- 
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers