Re: Cancelling of autovacuums considered harmful

On 02/27/14 10:43, Scott Marlowe wrote:
> On Wed, Feb 26, 2014 at 5:40 PM, Steve Crawford
> <scrawford@pinpointresearch.com> wrote:
>> On 02/26/2014 08:56 AM, Alvaro Herrera wrote:
>>>
>>> ...
>>>
>>> No matter how heavily updated, regular activity should not cause
>>> autovacuum kills.  Only heavier operations would do that (say ALTER
>>> TABLE, etc).
>>
>>
>> "Considered harmful" got my attention. What, if any, known harm is caused?
>>
>> We have many errors of this type but in our case most are due to batch
>> processes that have a vacuum embedded at appropriate points in the string of
>> commands in order to avoid excessive bloat and to ensure the tables are
>> analyzed for the following steps. Occasionally the autovacuum triggers
>> before the manual but gets canceled.
>>
>> Any harm?
>
> We have some rather large tables that have never been autovacuumed. At
> first I was thinking it was due to pgsql cancelling them due to load
> etc. But if it's slony getting in the way then cancelling them is
> still harmful, it's just not postgres' fault.

Slony (even the very old 1.2) does not cancel anything explicitly.


Jan

--
Jan Wieck
Senior Software Engineer
http://slony.info