| From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
|---|---|
| To: | Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Kouhei Kaigai <kaigai(at)ak(dot)jp(dot)nec(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: DBT-3 with SF=20 got failed |
| Date: | 2015-09-24 11:51:27 |
| Message-ID: | CA+TgmoYPyQTsSf6gMrRt5SWnCHz8mLOKwqNp3S5OeW4S1_tFeA@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Thu, Sep 24, 2015 at 5:50 AM, Tomas Vondra
<tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
> I however quite dislike the dismissal of the possible impact. It should be
> the responsibility of the person introducing the change to show that no such
> impact actually exists, not just waving it off as "unbased on any evidence"
> when there's no evidence presented.
So, we're talking about determining the behavior in a case that
currently fails. Making it behave like a case that currently works
can't but be an improvement. Making it do something that currently
never happens might be better still, or it might be equivalent, or it
might be worse. I just don't buy the argument that somebody's got to
justify on performance grounds a decision not to allocate more memory
than we currently ever allocate. That seems 100% backwards to me.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tomas Vondra | 2015-09-24 11:57:53 | Re: PATCH: use foreign keys to improve join estimates v1 |
| Previous Message | Stephen Frost | 2015-09-24 11:26:38 | Re: No Issue Tracker - Say it Ain't So! |