Re: curval was Re: is PG able to handle a >500 GB Database? - Mailing list pgsql-general

From Florent Guillaume
Subject Re: curval was Re: is PG able to handle a >500 GB Database?
Date
Msg-id 20010121153949.A4189@twin.efge.org
Whole thread Raw
In response to Re: curval was Re: is PG able to handle a >500 GB Database?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
> > On a different note.  OID's are not guaranteed to be unique within a table?
>
> Not unless you put a unique index on its OID column.  Of course, you
> won't actually see a conflict until you've been running your database
> long enough to wrap around the OID counter...


I think it would be a good thing to update the documentation, because
it's misleading at best :

 oid
  stands for the **unique** identifier of an instance which is added
  by Postgres to all instances automatically. Oids **are not reused**
  and are 32 bit quantities.

Bruce's book even starts a section with :

 Every row in POSTGRESQL is assigned a **unique**, normally invisible
 number called an object identification number (OID). When the software
 is initialized with initdb, a counter is created and set to
 approximately seventeen-thousand. The counter is used to **uniquely**
 number every row. Although databases may be created and destroyed, the
 counter continues to increase. It is used by all databases, so
 identification numbers are always **unique**. **No two rows in any table or
 in any database will ever have the same object ID.**



(emphasis mine)

Florent
--
<florent.guillaume@mail.com>

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