Re: Performance degradation of REFRESH MATERIALIZED VIEW

On Tue, May 11, 2021 at 02:46:35PM -0400, Andrew Dunstan wrote:
> On 5/11/21 2:23 PM, Alvaro Herrera wrote:
>> 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.

Well, that's an option on the table and a possibility, so I am listing
it as a possible exit path as a potential solution, as much as a
different optimization is another exit path to take care of this item
:)

>> 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.
>
> I agree with all of this. Right now I'm only concerned if there isn't
> work apparently being done on some issue.

If that's the consensus reached, that's fine by me as long as we don't
keep a 25% performance regression. Now, looking at the patch
proposed, I have to admit that this looks like some redesign of an
existing feature, so that stresses me a bit in a period when we are
aiming at making things stable, because this has a risk of making a
part of the code more unstable. And I've had my share of calls over
the last years in such situations, not only with Postgres, FWIW, so I
may just sound like a conservative guy with a conservative hat.
--
Michael