Re: Numbering Rows (SEQUENCE, OID) questions

On Sunday, December 16, 2001, at 11:42 AM, Stephan Szabo wrote:

> On Sun, 16 Dec 2001, Terrence Brannon wrote:
>
>> The Momjian book is excellent (in spite of some of the bonehead
>> reviews on amazon.com). I just finished the "Numbering Rows"
>> section and have a few questions. None of these were in the FAQ,
>> BTW.
>>
>> 1 - are OIDs ever re-used if rows are deleted?
>
> OIDs wraparound, but they don't just fill holes, so uniqueness
> isn't guaranteed unless you have something like a unique index
> on oid.

Where do you get this information? If I am reading the Momjian
book correctly, it disagrees with you:

Every row in POSTGRESQL is assigned a unique, normally invisible
number called an object identification number (OID). When the
software is initialized with initdb , 12.1 a counter is created
and set to approximately seventeen-thousand. 12.2 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.