Re: AutoVacuum starvation from sinval messages

On 9 November 2012 14:16, Robert Haas <robertmhaas@gmail.com> wrote:
> On Fri, Nov 9, 2012 at 9:02 AM, Simon Riggs <simon@2ndquadrant.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?

You asked what provokes starvation, and the answer is nothing anymore,
since Tom's commit. No confusion here...

-- Simon Riggs                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services