Re: vacuum, performance, and MVCC

Bruce Momjian <bruce(at)momjian(dot)us> writes:
> I think at some point we have to admit that _polling_ the tables, which
> is what autovacuum does, just isn't going to work well, no matter how
> much it is tweeked, and another approach should be considered for
> certain workload cases.

Autovacuum polls in its current, first-generation implementation;
what I said upthread was it needs to be smarter than that. I am not
sure how you get from that to the conclusion that the very next step
is to abandon the vacuuming approach altogether.

What I see in this discussion is a huge amount of "the grass must be
greener on the other side" syndrome, and hardly any recognition that
every technique has its downsides and complications. Furthermore,
I do not believe that this project has the ability to support multiple
fundamental storage models, as a number of people seem to be blithely
suggesting. We're having a hard enough time debugging and optimizing
*one* storage model. I think the correct path forward is to stick with
the same basic storage model and vacuuming concept, and address the
known performance issues with better-optimized vacuuming. No, it will
never be perfect for every scenario, but we can certainly make it much
better than it is now, without risking killing the project by
introducing undebuggable, unmaintainable complexity.

regards, tom lane