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.