Re: [SQL] maximum number of rows in table - what about oid limits?

--- Stephan Szabo <sszabo(at)megazone23(dot)bigpanda(dot)com> wrote:
> On Wed, 6 Jun 2001, John Scott wrote:
>
> > well i wasn't interested in using oids in my application.
> > i was curious about the relationship oids
> > and the tuple/row limit.
> >
> > i guess if what you say is true, the oids are NOT used internally
> > by postgres. this seems odd.
>
> > so, i guess my question still stands ... what happens when oids wrap?
> > are oids nothing more than a sequence with an index,
> > not used at all internally?
>
> They are used for references between system tables. That's why
> you'll get intermittent failures on things like create statements after
> rollover (system tables may have unique index on oid).
> As far as I know the system doesn't do stuff with the oid on user rows.
>
>

hmmm. guess i'm still not getting a clear picture on what
happens when oid's wrap? just seems like an obvious question.
if i wrap twice, things could get very wicked, indeed.

if i'm not comfortable with oid wrapping, then doesn't this imply
that postgres can only handle 2^32 tuples (or 2^31 - 1) -
this number of rows per table is relatively small by today's PC standards.
just converting/bulk loading an existing large commercial database into
postgres would expose this issue ;-)

what am i missing here? i am comfortable not using oids
in application logic. that' pretty standard.

my question is, since oid's are used by the
postgres kernel, what effect does oid wrapping have upon
the stability of the database. for example, does oid wrapping mean
i might clash with oid's in the system tables.

i'll poke around the source. just hoped somebody could
shed some light on what seemed like an obvious question.

thanks-john

=====
John Scott (john(at)august(dot)com)
Senior Partner
August Associates

email: john(at)august(dot)com
web: http://www.august.com/~jmscott

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