On Mon, 12 Aug 2024 at 20:34, John Naylor wrote:
> I just remembered an article I read a while back by a compiler
> engineer who said that compilers have heuristics that treat NULL
> pointers as "unlikely" since the most common reason to test that is so
> we can actually dereference it and do some
On Sun, Jun 30, 2024 at 10:24 PM Tom Lane wrote:
> In general, we have a policy of using likely/unlikely very sparingly,
> and only in demonstrably hot code paths. This hook call certainly
> doesn't qualify as hot.
I just remembered an article I read a while back by a compiler
engineer who said
Hi,
On 2024-06-30 16:47:02 +0200, Matthias van de Meent wrote:
> While hooks are generally not installed by default, I would advise
> against marking the hooks as unlikely, as that would unfairly penalize
> the performance of extensions that do utilise this hook (or hooks in
> general when applied
On Mon, 1 Jul 2024 at 14:08, Peter Geoghegan wrote:
>
> On Sun, Jun 30, 2024 at 11:23 AM Tom Lane wrote:
> > if (trouble)
> > ereport(ERROR, ...);
> >
> > could be interpreted as
> >
> > if (unlikely(trouble))
> > ereport(ERROR, ...);
> >
> > But I
On Sun, Jun 30, 2024 at 11:23 AM Tom Lane wrote:
> The real win would be if constructs like
>
> if (trouble)
> ereport(ERROR, ...);
>
> could be interpreted as
>
> if (unlikely(trouble))
> ereport(ERROR, ...);
>
> But I surely don't want to make thou
Hi Tom ,Matthias
Thank you for your explanation.Maybe future compilers will be able to
do intelligent prediction?
Thanks
Tom Lane 于2024年6月30日周日 23:23写道：
> Matthias van de Meent writes:
> > On Sun, 30 Jun 2024, 15:56 wenhui qiu, wrote:
> >> if (unlikely(ExecutorRun_hook)),
>
> > While ho
Matthias van de Meent writes:
> On Sun, 30 Jun 2024, 15:56 wenhui qiu, wrote:
>> if (unlikely(ExecutorRun_hook)),
> While hooks are generally not installed by default, I would advise
> against marking the hooks as unlikely, as that would unfairly penalize
> the performance of extensions that do
On Sun, 30 Jun 2024, 15:56 wenhui qiu, wrote:
>
> Hi Hackers
>When I saw this document:https://en.wikipedia.org/wiki/Branch_predictor, I
> thought of Linux likely() vs unlikely() and thus thought that there are some
> code segments in src/backend/executor/execMain.c that can be optimized.
>
Hi Hackers
When I saw this document:https://en.wikipedia.org/wiki/Branch_predictor,
I thought of Linux likely() vs unlikely() and thus thought that there are
some code segments in src/backend/executor/execMain.c that can be optimized.
For example :
if (ExecutorStart_hook)
(*ExecutorStart_hook) (
