Horton

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

Thomas Munro <thomas.munro@gmail.com>

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From: Thomas Munro <thomas.munro@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: John Naylor <john.naylor@enterprisedb.com>, Robert Haas <robertmhaas@gmail.com>, Kyotaro Horiguchi <horikyota.ntt@gmail.com>, Justin Pryzby <pryzby@telsasoft.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-06-22T04:24:06Z
Lists: pgsql-hackers

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On Wed, Jun 22, 2022 at 2:54 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> 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 the record, the third idea proposed was to use 1 for the first
byte, so that 0 is reserved for NULL and works with memset(0).  Here's
an attempt at that.

Commits

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

  2. Suppress compiler warning in relptr_store().