| From: | Peter Geoghegan <pg(at)bowt(dot)ie> |
|---|---|
| To: | Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Greg Stark <stark(at)mit(dot)edu>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: The case for removing replacement selection sort |
| Date: | 2017-09-11 16:09:38 |
| Message-ID: | CAH2-WzmAx87+SAfFH_DHYkjLdiKm=b_n8aMVQ-vBpFvM1QfqMQ@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Mon, Sep 11, 2017 at 8:47 AM, Tomas Vondra
<tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
> The question is what is the optimal replacement_sort_tuples value?
See my remarks to Robert just now.
I think that it's incredibly hard to set replacement_sort_tuples
sensibly in 9.6. As of Postgres 10, it is much more likely to hurt
than to help, because of the enhancements to merging that went into
Postgres 10 reduced the downside of not using replacement selection.
And so, for Postgres 11 replacement_sort_tuples deserves to be
removed.
--
Peter Geoghegan
| From | Date | Subject | |
|---|---|---|---|
| Next Message | amul sul | 2017-09-11 16:15:04 | Re: [POC] hash partitioning |
| Previous Message | Peter Geoghegan | 2017-09-11 16:06:19 | Re: The case for removing replacement selection sort |