Re: Performance degradation of REFRESH MATERIALIZED VIEW

On 2021-May-11, Michael Paquier wrote:

> Hmm. Is that really something we should do after feature freeze? A
> 25% degradation for matview refresh may be a problem for a lot of
> users and could be an upgrade stopper. Another thing we could do is
> also to revert 7db0cd2 and 39b66a9 from the v14 tree, and work on a
> proper solution for this performance problem for matviews for 15~.
>
> Thoughts?

My main thought while reading this thread is about the rules of feature
freeze. I mean, we are indeed in feature freeze, so no new features
should be added. But that doesn't mean we are in code freeze. For the
period starting now and until RC (which is a couple of months away
still) we should focus on ensuring that the features we do have are in
as good a shape as possible. If that means adding more code to fix
problems/bugs/performance problems in the existing code, so be it.
I mean, reverting is not the only tool we have.

Yes, reverting has its place. Moreover, threats of reversion have their
place. People should definitely be working towards finding solutions to
the problems in their commits lest they be reverted. However, freezing
*people* by saying that no fixes are acceptable other than reverts ...
is not good.

So I agree with what Andres is saying downthread: let's apply the fix he
proposed (it's not even that invasive anyway), and investigate the
remaining 5% and see if we can find a solution. If by the end of the
beta process we can definitely find no solution to the problem, we can
revert the whole lot then.

--
Álvaro Herrera 39°49'30"S 73°17'W