| From: | Bruce Momjian <bruce(at)momjian(dot)us> |
|---|---|
| To: | Jim Nasby <Jim(dot)Nasby(at)BlueTreble(dot)com> |
| Cc: | Andres Freund <andres(at)anarazel(dot)de>, Sawada Masahiko <sawada(dot)mshk(at)gmail(dot)com>, Greg Stark <stark(at)mit(dot)edu>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Jeff Janes <jeff(dot)janes(at)gmail(dot)com> |
| Subject: | Re: Freeze avoidance of very large table. |
| Date: | 2015-04-23 00:55:40 |
| Message-ID: | 20150423005540.GH13362@momjian.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Wed, Apr 22, 2015 at 06:36:23PM -0500, Jim Nasby wrote:
> On 4/22/15 6:12 PM, Bruce Momjian wrote:
> >My point is that for the life of 200M transactions, you would have the
> >overhead of an additional file per table in the file system, and updates
> >of that. I just don't know if the overhead over the long time period
> >would be smaller than the VACUUM FREEZE. It might be fine --- I don't
> >know. People seem to focus on the big activities, while many small
> >activities can lead to larger slowdowns.
>
> Ahh. This wouldn't be for the life of 200M transactions; it would be
> a permanent fork, just like the VM is.
Right. My point is that either you do X 2M times to maintain that fork
and the overhead of the file existance, or you do one VACUUM FREEZE. I
am saying that 2M is a large number and adding all those X's might
exceed the cost of a VACUUM FREEZE.
--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ Everyone has their own god. +
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Bruce Momjian | 2015-04-23 00:57:37 | Re: Shouldn't CREATE TABLE LIKE copy the relhasoids property? |
| Previous Message | Michael Paquier | 2015-04-23 00:36:54 | Re: TABLESAMPLE patch |