Re: Hash index build performance tweak from sorting

On 11/23/22 14:07, David Rowley wrote:
> On Fri, 18 Nov 2022 at 03:34, Tomas Vondra
> <tomas.vondra@enterprisedb.com> wrote:
>> I did some simple benchmark with v2 and v3, using the attached script,
>> which essentially just builds hash index on random data, with different
>> data types and maintenance_work_mem values. And what I see is this
>> (median of 10 runs):
> 
>> So to me it seems v2 performs demonstrably better, v3 is consistently
>> slower - not only compared to v2, but often also to master.
> 
> Could this just be down to code alignment changes?  There does not
> really seem to be any fundamental differences which would explain
> this.
> 

Could be, but then how do we know the speedup with v2 is not due to code
alignment too?


regards

-- 
Tomas Vondra
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