Re: Should we cacheline align PGXACT?

On Fri, Aug 19, 2016 at 4:46 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru> writes:
> > originally this idea was proposed by Andres Freund while experimenting
> with
> > lockfree Pin/UnpinBuffer [1].
> > The patch is attached as well as results of pgbench -S on 72-cores
> > machine. As before it shows huge benefit in this case.
>
> That's one mighty ugly patch. Can't you do it without needing to
> introduce the additional layer of struct nesting?
>

That's worrying me too.
We could use anonymous struct, but it seems to be prohibited in C89 which
we stick to.
Another idea, which comes to my mind, is to manually calculate size of
padding and insert it directly to PGXACT struct. But that seems rather
ugly too. However, it would be ugly definition not ugly usage...
Do you have better ideas?

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company