| From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
|---|---|
| To: | Simon Riggs <simon(at)2ndquadrant(dot)com> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: AutoVacuum starvation from sinval messages |
| Date: | 2012-11-09 14:16:56 |
| Message-ID: | CA+TgmoYUmv7Tt6CG-d-C-2RPjmEw+WJb8EzFvx8v0VEvLbKL0w@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Fri, Nov 9, 2012 at 9:02 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>> So, do we need a sinval overrun or just a sinval message to provoke
>> starvation? The former would be bad but the latter would be really,
>> really bad. IIRC the queue has 4K entries, and IIRC a single DDL
>> operation might provoke a couple of sinvals, but I'm thinking that
>> somebody would probably have to be creating >1024 temp tables a minute
>> to overrun the queue, which is very possible but not necessarily
>> common. OTOH, creating 1 temp table a minute would hit a much broader
>> swath of users.
>
> The point is moot because latches don't work that way anymore.
One of us is confused, because IIUC Tom just fixed this this morning,
and I'm trying to figure out how many users will be affected by it,
and how seriously. Like, do we need an immediate minor release?
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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