| From: | Heikki Linnakangas <hlinnaka(at)iki(dot)fi> |
|---|---|
| To: | Robert Haas <robertmhaas(at)gmail(dot)com>, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> |
| Cc: | "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: PATCH: adaptive ndistinct estimator v4 |
| Date: | 2015-04-30 21:31:48 |
| Message-ID: | 55429F44.2070205@iki.fi |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers pgsql-performance |
On 04/30/2015 01:57 PM, Robert Haas wrote:
>
> 2. There should be a compatibility GUC to restore the old behavior.
> The new behavior should be the default, because if we're not confident
> that the new behavior will be better for most people, we have no
> business installing it in the first place (plus few people will try
> it). But just in case it turns out to suck for some people, we should
> provide an escape hatch, at least for a few releases.
You can override the ndistinct estimate with ALTER TABLE. I think that's
enough for an escape hatch.
- Heikki
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Alvaro Herrera | 2015-04-30 22:18:08 | Re: initdb -S and tablespaces |
| Previous Message | David Steele | 2015-04-30 21:24:53 | Re: Auditing extension for PostgreSQL (Take 2) |
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Robert Haas | 2015-04-30 22:18:43 | Re: PATCH: adaptive ndistinct estimator v4 |
| Previous Message | Robert Haas | 2015-04-30 20:57:19 | Re: PATCH: adaptive ndistinct estimator v4 |