Обсуждение: OIDs wraparaound: postgresql (different versions) behavior

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OIDs wraparaound: postgresql (different versions) behavior

От
Francesco Dalla Ca'
Дата:
The PostgreSQL manual explain that from 8.1 the default behavior
(governed by default_with_oids system parameter) is to create user
tables "without oids".

Well, at the page
http://www.postgresql.org/docs/8.1/interactive/datatype-oid.html , the
manual report this:
"Object identifiers (OIDs) are used internally by PostgreSQL as primary
keys for various system tables."

What do i look and take care about the OID wraparound phenomenon? (On a
DBA perspective)
There is a possibility for a data inconsistency? (Or possibles database
blocking errors?)
What's the differents server behaviors for this phenomenon on differents
realeases?

Thank in advance for replies.

Best regards,
Francesco.

--
--------------------------------------------------
Francesco Dalla Ca'
Settore Gestione Sistemi CINECA
Via Magnanelli 6/3  40033 Casalecchio di Reno (BO)
Bologna, Italy             http://www.cineca.it
--------------------------------------------------


Re: OIDs wraparaound: postgresql (different versions) behavior

От
"Jim C. Nasby"
Дата:
On Mon, May 08, 2006 at 12:09:13PM +0200, Francesco Dalla Ca' wrote:
> The PostgreSQL manual explain that from 8.1 the default behavior
> (governed by default_with_oids system parameter) is to create user
> tables "without oids".
>
> Well, at the page
> http://www.postgresql.org/docs/8.1/interactive/datatype-oid.html , the
> manual report this:
> "Object identifiers (OIDs) are used internally by PostgreSQL as primary
> keys for various system tables."
>
> What do i look and take care about the OID wraparound phenomenon? (On a
> DBA perspective)
> There is a possibility for a data inconsistency? (Or possibles database
> blocking errors?)
> What's the differents server behaviors for this phenomenon on differents
> realeases?

In older versions if you wrapped the OID counter you'd get an error
about 'unable to create file' when you tried to create a new object and
the OID counter was pointing at a OID that had been used for another
object. That's fixed in 8.1.
--
Jim C. Nasby, Sr. Engineering Consultant      jnasby@pervasive.com
Pervasive Software      http://pervasive.com    work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf       cell: 512-569-9461