Re: Autovacuum launcher doesn't notice death of postmaster immediately

From: "Matthew T(dot) O'Connor" <matthew(at)zeut(dot)net>
To: Alvaro Herrera <alvherre(at)commandprompt(dot)com>
Cc: "Jim C(dot) Nasby" <decibel(at)decibel(dot)org>, Michael Paesold <mpaesold(at)gmx(dot)at>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Andrew Hammond <andrew(dot)george(dot)hammond(at)gmail(dot)com>, Peter Eisentraut <peter_e(at)gmx(dot)net>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Autovacuum launcher doesn't notice death of postmaster immediately
Date: 2007-06-08 22:40:59
Message-ID: 4669DAFB.1060600@zeut.net
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers pgsql-patches

Alvaro Herrera wrote:
> Jim C. Nasby escribió:
>> There *is* reason to allow setting the naptime smaller, though (or at
>> least there was; perhaps Alvero's recent changes negate this need):
>> clusters that have a large number of databases. I've worked with folks
>> who are in a hosted environment and give each customer their own
>> database; it's not hard to get a couple hundred databases that way.
>> Setting the naptime higher than a second in such an environment would
>> mean it could be hours before a database is checked for vacuuming.
>
> Yes, the code in HEAD is different -- each database will be considered
> separately. So the huge database taking all day to vacuum will not stop
> the tiny databases from being vacuumed in a timely manner.
>
> And the very huge table in that database will not stop the other tables
> in the database from being vacuumed either. There can be more than one
> worker in a single database.

Ok, but I think the question posed is that in say a virtual hosting
environment there might be say 1,000 databases in the cluster. Am I
still going to have to wait a long time for my database to get vacuumed?
I don't think this has changed much no?

(If default naptime is 1 minute, then autovacuum won't even look at a
given database but once every 1,000 minutes (16.67 hours) assuming that
there isn't enough work to keep all the workers busy.)

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Simon Riggs 2007-06-08 22:58:39 Re: Patch review process; Warning to patch submitters
Previous Message Alvaro Herrera 2007-06-08 22:06:47 Re: Autovacuum launcher doesn't notice death of postmaster immediately

Browse pgsql-patches by date

  From Date Subject
Next Message Alvaro Herrera 2007-06-08 23:19:40 Re: Autovacuum launcher doesn't notice death of postmaster immediately
Previous Message Simon Riggs 2007-06-08 22:37:32 Patch for recent PITR bug