Re: First draft of the PG 15 release notes

On 5/10/22 10:31 PM, David Rowley wrote:
> On Wed, 11 May 2022 at 14:02, Bruce Momjian <bruce@momjian.us> wrote:
>>
>> On Wed, May 11, 2022 at 12:39:41PM +1200, David Rowley wrote:
>>> I think the sort improvements done in v15 are worth a mention under
>>> General Performance.  The commits for this were 91e9e89dc, 40af10b57
>>> and 697492434.  I've been running a few benchmarks between v14 and v15
>>> over the past few days and a fairly average case speedup is about 25%.
>>> but there are cases where I've seen up to 400%.  I think the increase
>>> is to an extent that we maybe should have considered making tweaks in
>>> cost_tuplesort(). I saw some plans that ran in about 60% of the time
>>> by disabling Hash Agg and allowing Sort / Group Agg to do the work.
>>
>> Good point.  Do you have any suggested text?  I can't really see it
>> clearly based on the commits, except "sorting is faster".
> 
> If we're going to lump those into a single line then maybe something
> along the lines of:
> 
> * Reduce memory consumption and improve performance of sorting tuples in memory
> 
> I think one line is fine from a user's perspective, but it's slightly
> harder to know the order of the names in the credits given the 3
> independent commits.

I think a brief description following the one-liner would be useful for 
the release notes.

If you can share a few more details about the benchmarks, we can expand 
on the one-liner in the release announcement (as this sounds like one of 
those cool, buzz-y things :)

Jonathan