From: | Simon Riggs <simon(at)2ndQuadrant(dot)com> |
---|---|
To: | Jeff Janes <jeff(dot)janes(at)gmail(dot)com> |
Cc: | Bruce Momjian <bruce(at)momjian(dot)us>, Andres Freund <andres(at)anarazel(dot)de>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Pavan Deolasee <pavan(dot)deolasee(at)gmail(dot)com>, Greg Stark <stark(at)mit(dot)edu>, Simon Riggs <simon(at)2ndquadrant(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Michael Paquier <michael(dot)paquier(at)gmail(dot)com>, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>, Peter Eisentraut <peter_e(at)gmx(dot)net>, Robert Haas <robertmhaas(at)gmail(dot)com> |
Subject: | Re: Turning off HOT/Cleanup sometimes |
Date: | 2015-04-20 20:56:20 |
Message-ID: | CANP8+j+L7XVVpsAnBkBykFq_c_g2mF-NA2X88OSrS9ov14S_Zg@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On 20 April 2015 at 20:28, Jeff Janes <jeff(dot)janes(at)gmail(dot)com> wrote:
> But why should 1 SELECT or 20 SELECTs or 200 SELECTs have to do a job,
> while the user waits, which is fundamentally VACUUM's duty to do in the
> background?
>
Agreed. I don't see a % as giving us anything at all.
The idea is that we want to turn an O(N) problem for one query into an O(1)
task.
> The use case I see for this is when there is a mixed workload. There is
> one select which reads the entire table, and hundreds of thousands of
> selects/updates/insert that don't, and of course vacuum comes along every
> now and then and does it thing. Why should the one massive SELECT have
> horrible performance just because it was run right before autovacuum would
> have kicked in instead of right after if finished?
>
+1
--
Simon Riggs http://www.2ndQuadrant.com/
<http://www.2ndquadrant.com/>
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
From | Date | Subject | |
---|---|---|---|
Next Message | Jim Nasby | 2015-04-20 20:58:19 | Re: Freeze avoidance of very large table. |
Previous Message | Bruce Momjian | 2015-04-20 20:11:42 | Re: Shouldn't CREATE TABLE LIKE copy the relhasoids property? |