Thread: A slightly misleading comment in GetNewObjectId()

A slightly misleading comment in GetNewObjectId()

From
Thomas Munro
Date:
Hi hackers,

While contemplating plans to use new kinds of OIDs in buffer tags, I
noticed $SUBJECT.  It says:

 * Check for wraparound of the OID counter.  We *must* not return 0
 * (InvalidOid); and as long as we have to check that, it seems a good
 * idea to skip over everything below FirstNormalObjectId too. (This
 * basically just avoids lots of collisions with bootstrap-assigned OIDs
 * right after a wrap occurs, so as to avoid a possibly large number of
 * iterations in GetNewOid.)  Note we are relying on unsigned comparison.

That makes it sound like a mere optimisation, but since commit
8e18d04d4da user-created objects are not allowed to have OIDs below
that threshold.  So I propose the attached tweak.

-- 
Thomas Munro
http://www.enterprisedb.com

Attachment

Re: A slightly misleading comment in GetNewObjectId()

From
Tom Lane
Date:
Thomas Munro <thomas.munro@enterprisedb.com> writes:
> That makes it sound like a mere optimisation, but since commit
> 8e18d04d4da user-created objects are not allowed to have OIDs below
> that threshold.  So I propose the attached tweak.

+1

            regards, tom lane


Re: A slightly misleading comment in GetNewObjectId()

From
Robert Haas
Date:
On Thu, Aug 16, 2018 at 12:47 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Thomas Munro <thomas.munro@enterprisedb.com> writes:
>> That makes it sound like a mere optimisation, but since commit
>> 8e18d04d4da user-created objects are not allowed to have OIDs below
>> that threshold.  So I propose the attached tweak.
>
> +1

Looks good to me, too.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company


Re: A slightly misleading comment in GetNewObjectId()

From
Shawn Debnath
Date:
On Thu, Aug 16, 2018 at 11:36:58AM -0400, Robert Haas wrote:
> On Thu, Aug 16, 2018 at 12:47 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> > Thomas Munro <thomas.munro@enterprisedb.com> writes:
> >> That makes it sound like a mere optimisation, but since commit
> >> 8e18d04d4da user-created objects are not allowed to have OIDs below
> >> that threshold.  So I propose the attached tweak.
> >
> > +1
> 
> Looks good to me, too.

+1 and thanks for pointing to the commit which makes this a reality.


-- 
Shawn Debnath