Re: Use pg_nextpower2_* in a few more places - Mailing list pgsql-hackers

Thanks for having a look.

On Sun, 13 Jun 2021 at 00:50, Zhihong Yu <zyu@yugabyte.com> wrote:
> -       newalloc = Max(LWLockTrancheNamesAllocated, 8);
> -       while (newalloc <= tranche_id)
> -           newalloc *= 2;
> +       newalloc = pg_nextpower2_32(Max(8, tranche_id + 1));
>
> Should LWLockTrancheNamesAllocated be included in the Max() expression (in case it gets to a high value) ?

I think the new code will produce the same result as the old code in all cases.

All the old code did was finding the next power of 2 that's >= 8 and
larger than tranche_id.  LWLockTrancheNamesAllocated is just a hint at
where the old code should start searching from.  The new code does not
need that hint. All it seems to do is save the old code from having to
start the loop at 8 each time we need more space.

David