Re: [PoC] Improve dead tuple storage for lazy vacuum

On Thu, Dec 1, 2022 at 4:00 PM John Naylor <john(dot)naylor(at)enterprisedb(dot)com> wrote:
>
>
> On Wed, Nov 30, 2022 at 11:09 PM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> >
> > I've investigated this issue and have a question about using atomic
> > variables on palloc'ed memory. In non-parallel vacuum cases,
> > radix_tree_control is allocated via aset.c. IIUC in 32-bit machines,
> > the memory allocated by aset.c is 4-bytes aligned so these atomic
> > variables are not always 8-bytes aligned. Is there any way to enforce
> > 8-bytes aligned memory allocations in 32-bit machines?
>
> The bigger question in my mind is: Why is there an atomic variable in backend-local memory?

Because I use the same radix_tree and radix_tree_control structs for
non-parallel and parallel vacuum. Therefore, radix_tree_control is
allocated in DSM for parallel-vacuum cases or in backend-local memory
for non-parallel vacuum cases.

Regards,

--
Masahiko Sawada
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