Mercurial > hg > Papers > 2014 > nobuyasu-master

annotate paper/chapter3.tex @ 56:1d07365c60ff

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Writed conclstion
author Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
date Fri, 31 Jan 2014 21:37:40 +0900
parents faa708c2958b
children c5c761588168
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
50
faa708c2958b Added log
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 49
diff changeset
1 \chapter{分散データベースJungleの設計}
10
02c7fc1cda10 Writed description of TreeOperationLog
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 4
diff changeset
2
56
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
3 \section{分散バージョン管理システムによるデータの分散}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
4 Jungle は Git や Mercurial といった分散バージョン管理システムの機能を参考に作られている.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
5 分散バージョン管理システムとは, 多人数によるソフトウェア開発において変更履歴を管理するシステムである.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
6 % 反対の意味の言葉として集中型バージョン管理システムがある.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
7 分散管理システムでは開発者それぞれがローカルにリポジトリのクローンを持ち, 開発はこのリポジトリを通すことで進められる(図\ref{fig:distributed_repo}).
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
8 ローカルのリポジトリは独立に損刺し, サーバ上にあるリポジトリや他人のリポジトリで行われた変更履歴を取り込みアップデートにかけることができる.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
9 また逆に, ローカルのリポジトリに開発者自身がかけたアップデートを他のリポジトリへと反映させることもできる.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
10 分散管理システムでは, どれかリポジトリが壊れたとしても, 別のリポジトリからクローンを行うことができる.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
11 ネットワークに障害が発生しても, ローカルにある編集履歴をネットワーク復旧後に伝えることができる.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
12 そのため, 可用性と分断耐性が高いと言える.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
13 % 分散管理システムは結果整合性をとることを述べる.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
14 % 結果整合性の話を先にどっかでしたほうがいいかも
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
15 \begin{figure}[htpb]
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
16 \begin{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
17 \includegraphics[scale=0.7]{figures/distributed_repository.pdf}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
18 \caption{分散バージョン管理システム}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
19 \label{fig:distributed_repo}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
20 \end{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
21 \end{figure}
11
b87deec129df Added images
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 10
diff changeset
22
56
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
23
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
24 \subsection{マージによるデータ変更衝突の解決}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
25 分散管理システムでは, データの更新時において衝突が発生する時がある.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
26 それは, 分散管理システムを参考にしている Jungle においても起こる問題である.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
27 データの変更を行うときには, 元のデータに編集が加えられている状態かもしれない.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
28 Jungle はリクエストがきた場合, 現在もっているデータを返す.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
29 そのためデータは最新のものであるかは保証されない.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
30 この場合, 古いデータに編集が加えられ, それを更に最新のデータへ伝搬させなければならない.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
31 このように他のリポジトリにより先にデータ編集が行われており, データの伝搬が素直にできない状態を
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
32 衝突という.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
33 この衝突を解決する手段が必要である.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
34 分散管理システムでは衝突に対してマージと呼ばれる作業で解決をはかる.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
35 マージは, 相手のリポジトリのデータ編集履歴を受け取り, ローカルにあるリポジトリの編集と合わせる作業である.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
36 データ衝突に対して Jungle はアプリケーションレベルでのマージを実装して貰うことで解決をはかる.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
37
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
38 以下にマージが必要な場合とそうでない場合のデータ編集についての図を示す(図\ref{fig:tree_conflict1},\ref{fig:tree_conflict2},\ref{fig:tree_conflict3}).
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
39
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
40 \begin{figure}[htpb]
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
41 \begin{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
42 \includegraphics[scale=0.48]{figures/tree_conflict.pdf}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
43 \caption{衝突の発生しないデータ編集}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
44 \label{fig:tree_conflict1}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
45 \end{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
46 \end{figure}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
47
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
48 \begin{figure}[htpb]
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
49 \begin{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
50 \includegraphics[scale=0.48]{figures/tree_conflict3.pdf}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
51 \caption{自然に衝突を解決できるデータ編集}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
52 \label{fig:tree_conflict2}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
53 \end{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
54 \end{figure}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
55
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
56 \begin{figure}[htpb]
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
57 \begin{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
58 \includegraphics[scale=0.48]{figures/tree_conflict2.pdf}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
59 \caption{衝突が発生するデータ編集}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
60 \label{fig:tree_conflict3}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
61 \end{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
62 \end{figure}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
63
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
64
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
65 \section{ネットワークトポロジーの形成}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
66 分散管理システムを参考に Jungle でもそれぞれのデータベースが独立に
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
67 動くようにしたい.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
68 そのために必要なことはトポロジーの形成と, サーバノード間でのデータアクセス機構である.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
69 また, データ分散のために形成したトポロジー上で扱うデータを決めなければならない.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
70
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
71
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
72 \subsection{ツリートポロジーの形成}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
73 分散データーベス Jungle で形成されるネットワークトポロジーはツリー構造を想定している.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
74 ツリー構造ならば, データの整合性をとる場合, 一度トップまでデータを伝搬させることで行える.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
75 トップもしくはトップまでの間にあるサーバノードでデータ伝搬中に衝突が発生したらマージを行い, マージの結果を改めて伝搬すれば
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
76 よいからである.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
77 また, リング型, スター型, メッシュ側ではデータ編集の結果を他サーバノードに流すとき
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
78 流したデータが自分自身にくることにより発生するループに気をつける必要がある.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
79 ツリー構造の場合は, サーバノード同士の繋がりで閉路が無い.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
80 そのため, 自分自身が行ったデータ編集の履歴を繋がっているノードに送信するだけですむ.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
81 このルーティングの方式はスプリットホライズンと呼ばれるものである.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
82
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
83 \begin{figure}[htpb]
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
84 \begin{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
85 \includegraphics[scale=0.70]{figures/network_topology_tree.pdf}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
86 \caption{ツリー型のNetwork Topology}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
87 \label{fig:topology_tree}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
88 \end{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
89 \end{figure}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
90
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
91
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
92 \subsection{トポロジーの形成手段}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
93 Jungle で使用するネットワークトポロジーはツリー型を考えているが, リング型やメッシュ型といった
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
94 他のネットワークトポロジーによる実装に関しても試す余地はある.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
95 そのため, ツリーだけでなく, 自由にネットワークトポロジーの形成を行えるようにしたい.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
96
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
97 \begin{figure}[htpb]
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
98 \begin{minipage}{0.5\hsize}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
99 \begin{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
100 \includegraphics[scale=0.7]{figures/network_topology_ring.pdf}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
101 \caption{リング型のトポロジー}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
102 \label{fig:topology_ring}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
103 \end{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
104 \end{minipage}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
105 \begin{minipage}{0.5\hsize}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
106 \begin{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
107 \includegraphics[scale=0.7]{figures/topology_mesh.pdf}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
108 \caption{メッシュ型のトポロジー}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
109 \label{fig:topology_mesh}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
110 \end{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
111 \end{minipage}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
112 \end{figure}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
113
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
114
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
115 そこで当研究室で開発を行っている並列分散フレームワークである Alice を使用する.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
116 Alice はユーザが望んだマシンへの接続や必要なデータへのアクセスを行う機構と, 接続トポロジー
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
117 形成機能を提供している.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
118
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
119 % トポロジー形成の説明をする. 重要さなども。
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
120 % トポロジーの形成は容易ではない.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
121 % Alice が必要な機能を提供してくれることを述べる
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
122 % Alice はトポロジー形成の機能を提供している
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
123 % トポロジー間でのデータの受け渡す機能も提供している
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
124
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
125
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
126 \section{並列分散フレームワークAlice}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
127 Alice は当研究室で開発している並列分散フレームワークである.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
128 Alice はデータを DataSegment, タスクを CodeSegment という単位で扱うプログラミングを提供している.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
129 コードの部分となる CodeSegment は, 計算に必要なデータである DataSegment が揃い次第実行が行われる(図\ref{fig:cs_ds}).
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
130 CodeSegment の結果により出力される新たなデータでは, 別の CodeSegment が実行されるための DataSegment となる.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
131 DataSegment と CodeSegment の組み合わせにより並列・分散プログラミングの依存関係が表される.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
132
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
133 \begin{figure}[htpb]
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
134 \begin{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
135 \includegraphics[scale=0.70]{figures/cs_ds.pdf}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
136 \caption{DataSegment と CodeSegment によるプログラムの流れ}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
137 \label{fig:cs_ds}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
138 \end{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
139 \end{figure}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
140
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
141 \subsection{MessagePack によるシリアライズ}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
142 Alice では DataSegment のデータ表現に MessagePack(http://msgpack.org) を利用している.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
143 MessagePack はオブジェクトをバイナリへと変換させるシリアライズライブラリである.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
144 Alice によりネットワークを介してデータにアクセスするときは, そのデータが MessagePack でシリアライズが
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
145 行えることが条件である.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
146
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
147
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
148
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
149 \section{Jungle のデータ分散}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
150 Alice によりトポロジーの形成とデータアクセスの機構が提供された.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
151 後はデータ分散の為にどのデータをネットワークに流すのか決めなければならない.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
152 そこで選ばれたのが TreeOperationLog である.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
153 TreeOperationLog はデータ編集の履歴になる.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
154 どの Node にどのような操作をしたのかという情報が入っている.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
155 この TreeOperationLog を Alice を使って他サーバノードに送り, データの編集をしてもらうことで
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
156 同じデータを持つことが可能となる.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
157 Alice を用いるため, この TreeOperationLog は MessagePack によりシリアライズ可能な形にすることが
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
158 必要である.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
159
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
160
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
161 \subsection{CAP 定理と Jungle}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
162 ここまでの Jungle の設計を踏まえて, CAP 定理における Jungle の立ち位置を考える.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
163 分散管理バージョンのように独立したリポジトリもち, それぞれが独自の変更を加えることが
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
164 行えることで一貫性はゆるい.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
165 だが, ネットワークから切断されてもローカルで行ったデータの変更をネットワーク復旧後で伝搬できる
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
166 ことと, リクエストに対し持っているデータをすぐに返すことができる.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
167 つまり Jungle は可用性と分断耐性に優れたデータベースを目指している.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
168 第2章で紹介した既存のデータベースと Jungle との CAP 定理の関係を図\ref{fig:cap_theorem}に示す.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
169
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
170 \begin{figure}[htpb]
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
171 \begin{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
172 \includegraphics[scale=0.7]{figures/cap_theorem.pdf}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
173 \caption{CAP 定理における各データベースの立ち位置}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
174 \label{fig:cap_theorem}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
175 \end{center}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
176 \end{figure}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
177
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
178
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
179
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
180
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
181 \section{ログによるデータの永続性}
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
182 % TreeOperationLog(ログ)をシリアライズ可能な形にしてデータをおくること
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
183 % シリアライズできる形にしたものをそのままHDに書き出すだけでログの永続性は行える
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
184 Jungle は非破壊でさらにオンメモリにデータを保持するため, 使用するメモリの容量が大きくなる.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
185 そのため, ハードディスクに書き出し, 一定の区切りで保持している過去のデータをメモリ上から掃除しなければならない.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
186 そこで, ログによるデータの永続性の実装を行う.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
187 ここでログをどのようなデータ表現でハードディスクへと書きだすかという問題が発生するが, これは Alice を使うことで
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
188 解決している.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
189 Alice を用いるため MessagePack によりシリアライズ可能な TreeOperationLog ができる.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
190 このシリアライズ可能な TreeOperationLog をそのままハードディスクへ書き込むこととでログの永続性ができる.
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
191
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
192
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
193
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
194
1d07365c60ff Writed conclstion
Nobuyasu Oshiro <dimolto@cr.ie.u-ryukyu.ac.jp>
parents: 50
diff changeset
195