Re: Comment - uniqueness of relfilenode

On Wed, Mar 5, 2014 at 8:54 PM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> On Mon, Nov 11, 2013 at 05:48:52PM +0100, Antonin Houska wrote:
>> On 11/10/2013 12:57 AM, Robert Haas wrote:
>> > On Thu, Nov 7, 2013 at 10:56 AM, Antonin Houska
>> > <antonin(dot)houska(at)gmail(dot)com> wrote:
>> >> catalog/catalog.c:GetNewRelFileNode() and its calls indicate that the
>> >> following change makes sense:
>> >>
>> >>
>> >> diff --git a/src/include/storage/relfilenode.h
>> >> b/src/include/storage/relfilenode.h
>> >> index 75f897f..7190974 100644
>> >> --- a/src/include/storage/relfilenode.h
>> >> +++ b/src/include/storage/relfilenode.h
>> >> @@ -55,7 +55,7 @@ typedef enum ForkNumber
>> >> * relNode identifies the specific relation. relNode corresponds to
>> >> * pg_class.relfilenode (NOT pg_class.oid, because we need to be able
>> >> * to assign new physical files to relations in some situations).
>> >> - * Notice that relNode is only unique within a particular database.
>> >> + * Notice that relNode is only unique within a particular tablespace.
>> >> *
>> >> * Note: spcNode must be GLOBALTABLESPACE_OID if and only if dbNode is
>> >> * zero. We support shared relations only in the "global" tablespace.
>> >>
>> >>
>> >> // Antonin Houska (Tony)
>> >
>> > Technically speaking, I think it's only guaranteed to be unique with a
>> > database-tablespace combination. In other words, the same OID can be
>> > reused as a relfilenode if *either* of those two values differs.
>>
>> You're right. I missed the fact that Postgres (unlike another DBMS that
>> I worked with) allows for tablespace to be shared across databases.
>
> I have update the C comment:
>
> < * Notice that relNode is only unique within a particular database.
> ---
> > * Notice that relNode is only unique within a particular tablespace.

Yep. But the new text is no more correct than the old text. Did you
read what I wrote upthread?

--
Robert Haas
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