Re: AutoVacuum starvation from sinval messages

On Thu, Nov 8, 2012 at 2:50 PM, Hannu Krosing <hannu(at)2ndquadrant(dot)com> wrote:
> On 11/08/2012 11:40 PM, Simon Riggs wrote:
>>
>> On 8 November 2012 20:36, Jeff Janes <jeff(dot)janes(at)gmail(dot)com> wrote:
>>
>>> It does not seem outrageous to me that there would be real-world
>>> conditions in which invalidations would be sent more than once a
>>> minute over prolonged periods, so this total starvation seems like a
>>> bug.
>>
>> Yes, its a bug, but do you really believe the above? In what cases?

We see lots of traffic on the mail list about people trying to dump
several hundred thousand tables, or they can only create one database
every two minutes, or truncating hundreds of tables at a time over and
over again gets slow, etc. I know little about the internal of the
invalidation code, but I would think doing that kind of thing must
generate a lot of them.

>>
> Could heavy use of temporary tables cause this ?

It looks like they do. I'm not sure what is being invalidated in
those cases, but something seems to be.

Cheers,

Jeff