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

<snip>
so, i guess my question still stands ... what happens when oids wrap?
<snip>

Answer: Very little. Just remember 2 things if you expect OIDs to wrap
in your application:

1. Don't key off of them. Use a sequence of your own.
2. Watch for creations and insertions to fail due to duplicate
OIDs. When the failure is due to a duplicate, simply retry
the operation again.

Tim

----- Original Message -----
From: "John Scott" <jmscott(at)yahoo(dot)com>
To: "Stephan Szabo" <sszabo(at)megazone23(dot)bigpanda(dot)com>
Cc: <pgsql-general(at)postgresql(dot)org>; <pgsql-sql(at)postgresql(dot)org>
Sent: Wednesday, June 06, 2001 11:45 AM
Subject: [GENERAL] Re: [SQL] maximum number of rows in table - what about
oid limits?

> 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?
>
> i
> --- Stephan Szabo <sszabo(at)megazone23(dot)bigpanda(dot)com> wrote:
> >
> > On 6 Jun 2001, jmscott(at)REMOVEMEyahoo(dot)com wrote:
> >
> > > postgresql docs claim an essentially unlimited number of
> > > rows per table.
> > >
> > > http://postgresql.crimelabs.net/users-lounge/limitations.html
> > >
> > > this doesn't make sense if each row has an oid.
> > > do more subtle side effects exist if the oid wraps?
> >
> > In general, unless you're relying on unique oids, you should be fine.
> > You probably don't want to use oid as a unique key in your tables for
that
> > reason. Of course, sequences aren't sufficient either (also being
> > int4) but some kind of int8 "sequence" mechanism would do it if you
expect
> > more than the int4 number of rows.
> >
> > You might have problems with creating system table entries with unique
> > oids after wraparound, but generally that can be fixed by trying again.
> > (Some of the system tables have a unique index on oid).
> >
>
>
> =====
> 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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