Rob Nikander <rob.nikander@gmail.com> writes:
> Are there guarantees about how this plpgsql behaves? It’s deleting from a table while it loops over it. So far it
seemslike the delete is logically after the select, as I hoped, and doesn’t interfere.
> for row in select * from some_stuff loop
> delete from some_stuff where …
> ...
> end loop;
Sure. A query will not see the effects of queries that start after it.
This isn't particularly plpgsql-specific.
Some qualifications are needed if you have triggers or volatile functions
in the first query (those *can* see later effects); but this usage seems
safe enough.
regards, tom lane