Re: sequence increment jumps?

On Thu, Jan 25, 2007 at 12:33:51 -0500,
John Smith <jayzee(dot)smith(at)gmail(dot)com> wrote:
> guys,
> i inserted 1 record into my database (default
> nextval('sequencename'::regclass) where (start 1 increment 1)). then i
> tried to insert 1 other record twice but both those inserts failed
> because of a domain check ("ERROR: value too long for type character
> varying(X)". when i was finally able to insert that record the
> sequence jumped 2 places. seems like it counted the failed inserts?

That is how sequences work. All your are guaranteed globally is that they
are unique. You can't rely on getting a sequence without gaps. Within a single
session you can get a guaranty that the values increase monotonicly if you
disallow wrap around for the sequence.