Re: Reducing the chunk header sizes on all memory context types

On Mon, Aug 29, 2022 at 7:17 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> David Rowley <dgrowleyml(at)gmail(dot)com> writes:
> > I suspect, going by all 3 failing animals being 32-bit which have a
> > MAXIMUM_ALIGNOF 8 and SIZEOF_SIZE_T of 4 that this is due to the lack
> > of padding in the MemoryChunk struct.
> > AllocChunkData and GenerationChunk had padding to account for
> > sizeof(Size) being 4 and sizeof(void *) being 8, I didn't add that to
> > MemoryChunk, so I'll do that now.
>
> Doesn't seem to have fixed it. IMO, the fact that we can get through
> core regression tests and pg_upgrade is a strong indicator that
> there's not anything fundamentally wrong with memory context
> management. I'm inclined to think the problem is in d2169c9985,
> instead ... though I can't see anything wrong with it.
>

Yeah, I also thought that way but couldn't find a reason. I think if
David is able to reproduce it on one of his systems then he can try
locally reverting both the commits one by one.

> Another possibility is that there's a pre-existing bug in the
> logical decoding stuff that your changes accidentally exposed.
>

Yeah, this is another possibility.

--
With Regards,
Amit Kapila.