Re: pg15b1: FailedAssertion("val > base", File: "...src/include/utils/relptr.h", Line: 67, PID: 30485)

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: John Naylor <john.naylor@enterprisedb.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, Justin Pryzby <pryzby@telsasoft.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>, Thomas Munro <thomas.munro@gmail.com>
Date: 2022-06-22T02:54:47Z
Lists: pgsql-hackers
John Naylor <john.naylor@enterprisedb.com> writes:
> On Wed, Jun 1, 2022 at 2:57 AM Robert Haas <robertmhaas@gmail.com> wrote:
>> ... So we can fix this by:
>> 1. Using a relative pointer value other than 0 to represent a null
>> pointer. Andres suggested (Size) -1.
>> 2. Not storing the free page manager for the DSM in the main shared
>> memory segment at byte offset 0.

> For this open item, the above two ideas were discussed as a short-term
> fix, and my reading of the thread is that the other proposals are too
> invasive at this point in the cycle. Both of them have a draft patch
> in the thread. #2, i.e. wasting MAXALIGN of space, seems the simplest
> and most localized. Any thoughts on pulling the trigger on either of
> these two approaches?

I'm still of the opinion that 0 == NULL is a good property to have,
so I vote for #2.

			regards, tom lane



Commits

  1. Fix relptr's encoding of the base address.

  2. Suppress compiler warning in relptr_store().