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Thread: OIDs

OIDs

From
Philip Reimer
Date:
Hi everyone.
I have a simple question which I couldn't find an answer to in any of the
PostgreSQL documentations. How long is an OID in bits? Or otherwise, is
there a limit to OIDs, how big is the biggest OID?
Thanks,
Philip

Re: OIDs

From
Joe Conway
Date:
Philip Reimer wrote:
> Hi everyone.
> I have a simple question which I couldn't find an answer to in any of the
> PostgreSQL documentations. How long is an OID in bits? Or otherwise, is
> there a limit to OIDs, how big is the biggest OID?
> Thanks,
> Philip
>

 From ~/pgsql/src/include/postgres_ext.h:
<snip>

/*
  * Object ID is a fundamental type in Postgres.
  */
typedef unsigned int Oid;

#define InvalidOid ((Oid) 0)

#define OID_MAX UINT_MAX
/* you will need to include <limits.h> to use the above #define */

</snip>

So, it depends on the size of unsigned int on your platform.
HTH,

Joe

Re: OIDs

From
Michael Loftis
Date:
In general, 32-bits.  Does depend on  how big an unsigned int happens to
be on your particular platform.  They can roll around back to the start
also so aren't a very good idea to use for uniqueness if you've got a
lot of rows you want tracked by oid...

Philip Reimer wrote:

>Hi everyone.
>I have a simple question which I couldn't find an answer to in any of the
>PostgreSQL documentations. How long is an OID in bits? Or otherwise, is
>there a limit to OIDs, how big is the biggest OID?
>Thanks,
>Philip
>
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