Stateless - Web DevelopmentYouTube↗  IA↗(long shot)
Education  9.2K views 35 likes 8 dislikes   23 Feb 2015
Udacity 651K subscribers United States YouTube↗


Please select the problem
You must specify your email and describe the problem in detail
Describe your problem in detail if it's not obvious

Click to Play Video Click to Play Video
Okay, so adding Memcache to Ascii Chan gave us two
memcacheをASCII Chanに導入した結果
new properties that are really nice. One is that our cache
改善した点が2つあります まず再起動後も
survives restarts. Before when we're using that dictionary cache, if we
キャッシュが消えないこと ディクショナリ･キャッシュの時には
updated our code, either locally or in production, our cache gets
ローカルでも本番モードでもコードを
cleared. That's not a good quality. Or if, you know, in
更新するとキャッシュは消えました 望ましいこととはいえません
production if Google for some reason. Moves us a different machine
Googleが本番モードでAPサーバを
or something like that. What's going to happen, our cache would get
変更する場合 キャッシュは
cleared. Which is also you know, it's not a good property,
消えます　それでは困りますね
especially if you have a lot of traffic. And
トラフィックが大量ならなおさらです
our app is now stateless, which is the key
次にアプリケーションがステートレスになり スケーリングが
to scaling. What stateless means is our app between
容易になります　ステートレスとは
any two requests, stores no state. And that means we
2つのリクエストが来たらアプリケーションに
ca, that, that a, a number of, a number
ステートを保持させないことです
of properties come from this. You know, there's no state
その恩恵はいくつもあります　リクエスト間に
between requests. Which means our apps are now interchangeable.
古い情報がないので アプリケーションが置き換え可能です
Which means we can have multiple apps without any drama.
複数のアプリケーションを容易に扱えるのです
You know, we have our load balancer, we have our Memcached.
ロードバランサとmemcachedの間に
And in between those two pieces of technology are as many
必要なだけAPサーバを配置できます
app servers as we need. You know, adding more app servers
APサーバの増設は簡単です
is easy. likewise, removing an app server is also easy and,
反対にAPサーバを削除するのも 容易で手間がかかりません
and not painful. And it means our apps can be scaled
つまりアプリケーションがキャッシュや
independently of. Our cache and our database. So we've got our
データベースとは独立してスケーリングされるのです
app servers. You know, we've got our, our database, and you
APサーバとデータベースがあります
know we've got our cache. And if we find ourselves needing more
そしてキャッシュです　もう少しAPサーバが
app servers, we can add one. Let's add our load balancer in here
必要であれば増設できます　ロードバランサも足せます
for good measure. So now I've got all these pieces. We need another
これですべての装備が整いました
app server we add one. If we need another Memcache, we add one.
まだAPサーバもmemcacheも必要ならば増設が可能です
Having lots of caches means we won't have to scale our database quite
キャッシュがたくさんあればデータベースの
so fast, but if we need more database, we talked about this in
スケーリングは急ぐ必要はありません
unit three. You know, we can go with replication or we can go
もし増設するならレッスン3で学んだレプリケーションや
with sharding. But now you're starting to see the the kind of the
シャーディングを使えますが 皆さんはもう
bigger picture of how a website might grow. If you're really data heavy.
Webサイトの拡張を大局的に見られます
You have lots of databases and maybe lots of caches. You know, if
重いデータを扱うなら データベースやキャッシュが多数必要です
your database is, is very read heavy but not [UNKNOWN] it's not actually
データベースの読み込みが遅くても
not a lot of data you would have more caches. If your, if
データ量が多くないならキャッシュを増設します
your application is very computationally intensive, maybe
アプリケーションを計算主体で利用するなら
you have lots of app servers and
APサーバを多く配置します
you don't need so much database support or not so much cache support.
データベースやキャッシュはあまり必要ありません
But what we want to do, is we want to make sure that all of
ここまでで確認しておきたいのは
these different pieces can grow independently.
それぞれを独立して拡張させられる点です
And that's kind of what scaling is
それがスケーリングです
all about, is putting yourself in a position so that when your app is
アプリケーションが様々な方法で制限を受けても
constrained in different ways, you can grow each part kind of independent of the
それぞれの部分を他とは関係なく拡張できるのです
others. And now that our app is stateless, it's really easy to do that. And
今や我々のアプリケーションはステートレスなので それが可能です
Memcache helps a lot because all of the, all of the state is either stored in
これもmemcachedのおかげです　ステートの格納場所は
cookies, the DB or Memcache, but not the apps. And that's really handy.
アプリケーションではなくクッキーやデータベース そしてmemcacheです　非常に便利ですね
Similar videos:

Locking and Memcache - Web Development
Udacity
5.6K views 16 likes 0 dislikes 27 May 2012100% match

Making Links
Udacity
53.9K views 21 likes 0 dislikes 23 Feb 2015100% match

Problems with Memcachedb - Web Development
Udacity
6K views 13 likes 0 dislikes 27 May 2012100% match

Port - Web Development
Udacity
15.8K views 18 likes 0 dislikes 23 Feb 2015100% match

Code Organization - Web Development
Udacity
7.2K views 25 likes 1 dislikes 27 May 2012100% match

Web 简介
Udacity
25.7K views 60 likes 0 dislikes 23 Feb 2015100% match

Inline Vs Block
Udacity
17.3K views 139 likes 5 dislikes 23 Feb 2015100% match

The Method Attribute - Web Development
Udacity
9.6K views 14 likes 8 dislikes 22 Apr 2012100% match

Best Browser Solution - Web Development
Udacity
9.6K views 22 likes 1 dislikes 23 Feb 2015100% match

Paragraph Tag - Web Development
Udacity
8.6K views 4 likes 0 dislikes 23 Feb 2015100% match

Shopping List Take 1 - Web Development
Udacity
841 views 1 likes 0 dislikes 23 Feb 2015100% match

Reddit Architecture - Web Development
Udacity
27.7K views 397 likes 3 dislikes 27 May 2012100% match

Bold Tag - Web Development
Udacity
53K views 29 likes 0 dislikes 23 Feb 2015100% match

Caching - Web Development
Udacity
12.1K views 102 likes 0 dislikes 23 Feb 2015100% match

App Server Architecture - Web Development
Udacity
14K views 52 likes 5 dislikes 27 May 2012100% match

Ad Networks - Web Development
Udacity
6.7K views 27 likes 3 dislikes 23 Feb 2015100% match

User Input - Web Development
Udacity
7.7K views 3 likes 0 dislikes 22 Apr 2012100% match

Query Parameters - Web Development
Udacity
22.6K views 78 likes 3 dislikes 23 Feb 2015100% match

Part 2 - Web Development
Udacity
643 views 2 likes 0 dislikes 07 May 2012100% match

Span and Div
Udacity
50.3K views 27 likes 1 dislikes 23 Feb 2015100% match

Google App Engine - Web Development
Udacity
10.1K views 13 likes 3 dislikes 17 Apr 2012100% match

Reddit Architecture 2 - Web Development
Udacity
11.1K views 88 likes 2 dislikes 27 May 2012100% match

Security - Web Development
Udacity
5.7K views 64 likes 0 dislikes 23 May 2012100% match

Cookie Headers - Web Development
Udacity
4.2K views 23 likes 1 dislikes 23 Feb 2015100% match

Datastore Types Solution - Web Development
Udacity
656 views 1 likes 0 dislikes 25 Apr 2012100% match

URL Encoding - Web Development
Udacity
13.7K views 17 likes 13 dislikes 22 Apr 2012100% match

Growing Reddit - Web Development
Udacity
82.7K views 484 likes 27 dislikes 27 May 2012100% match

Cookies - Web Development
Udacity
38.4K views 315 likes 11 dislikes 23 Feb 201580% match

Whitespace Solution - Web Development
Udacity
15.7K views 10 likes 1 dislikes 23 Feb 201573% match

Course Outline - Web Development
Udacity
46.2K views 169 likes 0 dislikes 23 Feb 201573% match


Settings Privacy About Contact Donate