Re: Why do we let autovacuum give up?

On Thu, Jan 23, 2014 at 12:53 PM, Josh Berkus <josh(at)agliodbs(dot)com> wrote:
> On 01/23/2014 12:34 PM, Joshua D. Drake wrote:
>>
>> Hello,
>>
>> I have run into yet again another situation where there was an
>> assumption that autovacuum was keeping up and it wasn't. It was caused
>> by autovacuum quitting because another process requested a lock.
>>
>> In turn we received a ton of bloat on pg_attribute which caused all
>> kinds of other issues (as can be expected).
>>
>> The more I run into it, the more it seems like autovacuum should behave
>> like vacuum, in that it gets precedence when it is running. First come,
>> first serve as they say.
>>
>> Thoughts?
>
> If we let autovacuum block user activity, a lot more people would turn
> it off.
>
> Now, if you were to argue that we should have some way to monitor the
> tables which autovac can never touch because of conflicts, I would agree
> with you.

Agree completely. Easy ways to monitor this would be great. Once you
know there's a problem, tweaking autovacuum settings is very hard and
misunderstood, and explaining how to be effective at it is a dark art
too.

-Harold