Re: Large Objects: Sizeof and Deleting Unlinked LOs

In article <4B72AEB3(dot)4000809(at)selestial(dot)com>,
Howard Cole <howardnews(at)selestial(dot)com> writes:

> Is there an SQL function to determine the size of a large object?

I'm using a pgsql helper function for that:

CREATE FUNCTION lo_size(oid oid) RETURNS integer
LANGUAGE plpgsql
AS $$
DECLARE
fd int;
res int;
i int;
BEGIN
fd = lo_open(oid, 262144); -- INV_READ
IF fd < 0 THEN
RAISE EXCEPTION 'lo_open returns %', fd;
END IF;
res = lo_lseek(fd, 0, 2); -- SEEK_END
IF res < 0 THEN
RAISE EXCEPTION 'lo_lseek returns %', res;
END IF;
i = lo_close(fd);
IF i < 0 THEN
RAISE EXCEPTION 'lo_close returns %', i;
END IF;
RETURN res;
END;
$$;

> Also, can I safely delete all the large objects in
> pg_catalog.pg_largeobject? For example:

> select lo_unlink(loid) from (select distinct loid from
> pg_catalog.pg_largeobject) as loids where loid not in (select my_oid
> from my_only_table_that_uses_large_objects)

Did you have a look at contrib/lo?