Re: Server process crash - Segmentation fault

Leif Jensen <leif(at)crysberg(dot)dk> writes:
> Could it be related to the OFFSET part of the statement ? I have another query on the same table without OFFSET, which seems to work fine.

Yeah, the specific code path here involves executing a stable (or possibly
immutable) SQL function in a LIMIT or OFFSET clause. I was able to
reproduce the crash like so:

create function foo(int) returns int as 'select $1 limit 1'
language sql stable;

begin;

declare c cursor for select * from int8_tbl limit foo(3);

select * from c;

move backward all in c;

select * from c;

commit;

You might be able to dodge the problem if you can make the SQL function
inline-able (the LIMIT 1 in my example is just to prevent that from
happening). A less appealing alternative is to mark the function
VOLATILE, which I think would also prevent this crash, but might have
negative performance consequences.

If you don't mind building your own PG then you could grab the actual fix
from our git repo; I should have something committed before long.

regards, tom lane