Re: ProjectSet

On 2 August 2018 at 21:17, Oliver Kohll <oliver(at)agilechilli(dot)com> wrote:
> Is there an explanation of ProjectSet anywhere?

Plan node types and what they each do are not very well documented
outside of the source code.

ProjectSet appears when the SELECT or ORDER BY clause of the query.
They basically just execute the set-returning function(s) for each
tuple until none of the functions return any more records.

Simple Example:

EXPLAIN SELECT generate_series(1,2);
QUERY PLAN
-------------------------------------------------
ProjectSet (cost=0.00..5.02 rows=1000 width=4)
-> Result (cost=0.00..0.01 rows=1 width=0)
(2 rows)

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