Re: tweaking NTUP_PER_BUCKET

On 12.7.2014 11:39, Simon Riggs wrote:
> On 11 July 2014 18:25, Tomas Vondra <tv(at)fuzzy(dot)cz> wrote:
>
>> Turns out getting this working properly will quite complicated.
>
> Lets keep this patch simple then. Later research can be another patch.

Well, the dense allocation is independent to the NTUP_PER_BUCKET
changes, and only happened to be discussed here because it's related to
hash joins. My plan was to keep it as a separate patch, thus not making
the NTUP patch any more complex.

> In terms of memory pressure, having larger joins go x4 faster has a
> much more significant reducing effect on memory pressure than
> anything else. So my earlier concerns seem less of a concern.

OK.

> So lets just this change done and then do more later.

There's no way back, sadly. The dense allocation turned into a
challenge. I like challenges. I have to solve it or I won't be able to
sleep.

regards
Tomas