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WIP: more restructuring

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Scott Lystig Fritchie 2015-04-20 21:21:11 +09:00
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35
doc/src.high-level/high-level-chain-mgr.tex
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@ -680,19 +680,18 @@ for an allegory in homage to the style of Leslie Lamport's original Paxos
paper.
\end{itemize}
\subsubsection{Aside: origin of the analogy to composing music}
\paragraph{Aside: origin of the analogy to composing music}
The ``humming'' part of humming consensus comes from the action taken
when the environment changes. If we imagine an egalitarian group of
people, all in the same room humming some pitch together, then we take
action to change our humming pitch if:
\begin{itemize}
\item Some member departs the room (because they witness the person
\item Some member departs the room (because we can witness the person
walking out the door) or if someone else in the room starts humming a
new pitch with a new epoch number.\footnote{It's very difficult for
the human ear to hear the epoch number part of a hummed pitch, but
for the sake of the analogy, assume that it can.}
for the sake of the analogy, let's assume that it can.}
\item If a member enters the room and starts humming with the same
epoch number but a different note.
\end{itemize}
@ -711,14 +710,38 @@ obeyed. Such safe management of Chain Replication metadata is our end goal.
See also: Section~\ref{sub:network-monitoring}.
In today's implementation, there is only a single criterion for
determining the available/not-available status of a remote server $S$:
is $S$'s projection store available. If yes, then we assume that all
$S$ is available. If $S$'s projection store is not available for any
reason, we assume $S$ is entirely unavailable. This simple single
criterion appears to be sufficient for humming consensus, according to
simulations of arbitrary network partitions.
\subsection{Calculating a new projection data structure}
See also: Section~\ref{sub:projection-calculation}.
TODO:
0. incorporate text from ORG file at all relevant places!!!!!!!!!!
1. calculating a new projection is straightforward
2. define flapping?
3. a simple criterion for flapping/not-flapping is pretty easy
4. if flapping, then calculate an ``inner'' projection
5. if flapping $\rightarrow$ not-flapping, then copy inner
$\rightarrow$ outer projection and reset flapping counter.
\subsection{Writing a new projection}
See also: Section~\ref{sub:proj-storage-writing}.
TODO:
1. We write a new projection based on flowchart A* and B* states and
state transtions.
TOOD: include the flowchart into the doc. We'll probably need to
insert it landscape?
\subsection{Adopting a new projection}
See also: Section~\ref{sub:proj-adoption}.
@ -758,6 +781,10 @@ epoch $E+1$.
See Section~\ref{sub:humming-rules-and-invariants} for detail about
these rules and invariants.
TODO:
1. We write a new projection based on flowchart A* and B* and C1* states and
state transtions.
\section{Just in case Humming Consensus doesn't work for us}
There are some unanswered questions about Machi's proposed chain