%% So, I'd tried this kind of "if everyone is doing it, then we
%% 'agree' and we can do something different" strategy before,
%% and it didn't work then. Silly me. Distributed systems
%% lesson #823: do not forget the past. In a situation created
%% by PULSE, of all=[a,b,c,d,e], b & d & e were scheduled
%% completely unfairly. So a & c were the only authors ever to
%% suceessfully write a suggested projection to a public store.
%% Oops.
%%
%% So, we're going to keep track in #ch_mgr state for the number
%% of times that this insane judgement has happened.
* Set max length of a chain at -define(MAX_CHAIN_LENGTH, 64).
* Perturb tick sleep time of each manager
* If a chain manager L has zero members in its chain, and then its local
public projection store (authored by some remote author R) has a projection
that contains L, then adopt R's projection and start humming consensus.
* Handle "cross-talk" across projection stores, when chain membership
is changed administratively, e.g. chain was [a,b,c] then changed to merely
[a], but that change only happens on a. Servers b & c continue to use
stale projections and scribble their projection suggestions to a, causing
it to flap.
What's really cool about the flapping handling is that it *works*. I
wasn't thinking about this scenario when designing the flapping logic, but
it's really nifty that this extra scenario causes a to flap and then a's
inner projection remains stable, yay!
* Add complaints when "cross-talk" is observed.
* Fix flapping sleep time throttle.
* Fix bug in the machi_projection_store.erl's bookkeeping of the
max epoch number when flapping.
I'd first thought that having that code there would be a kind of
useful reminder: please move me somewhere else. However, there's
quite a bit there that's "cluster of clusters" stuff and not
appropriate for the current short-term work.
