Re: New GUC autovacuum_max_threshold ?

> This is about how I feel, too. In any case, I +1'd a higher default
> because I think we need to be pretty conservative with these changes, at
> least until we have a better prioritization strategy. While folks may opt
> to set this value super low, I think that's more likely to lead to some
> interesting secondary effects. If the default is high, hopefully these
> secondary effects will be minimized or avoided.


There is also an alternative of making this GUC -1 by default, which
means it has not effect and any value larger will be used in the threshold
calculation of autovacuunm. A user will have to be careful not to set it too low, 
but that is going to be a concern either way.


This idea maybe worth considering as it does not change the default
behavior of the autovac threshold calculation, and if a user has cases in 
which they have many tables with a few billion tuples that they wish to 
see autovacuumed more often, they now have a GUC to make 
that possible and potentially avoid per-table threshold configuration.


Also, I think coming up with a good default will be challenging,
and perhaps this idea is a good middle ground.


Regards,

Sami