パフォーマンスの重要性
• UX
• JakobNielsen - Response Times: The 3 Important Limits
“1.0 second is about the limit for the user's flow of
thought to stay uninterrupted”
• KPI
• Google: Using site speed in web search ranking
• Aberdeen Group: study showed that a one second delay
in page load time equals 11% fewer page views, a 16%
decrease in customer satisfaction, and 7% loss in
conversions.
http://www.nngroup.com/articles/response-times-3-important-limits/
http://googlewebmastercentral.blogspot.jp/2010/04/using-site-speed-in-web-search-ranking.html
http://www.aberdeen.com/research/5136/ra-performance-web-application/content.aspx
Remix: Latency NumbersEvery Programmer Should Know(2014)
http://yuroyoro.net/latency.html
59.
コンテキストスイッチング
CPU CPU CPUCPU
process process process process process process process
process process process process process process process
process process process process process process process
OSによりスケジュール実行
60.
コンテキストスイッチング
CPU CPU CPUCPU
process process
process
process process process process
process process process process process process process
process process process process process process process
OSによりスケジュール実行
61.
コンテキストスイッチング
CPU CPU CPUCPU
process process process process process process process
process process process process process
process
process
process process process process process process process
OSによりスケジュール実行
MySQL の B+Tree
SECONDARYKEY
primary keyじゃないkey
リーフノードに
PRIMARYKEYが含まれ、
データはCLUSTEREDINDEX
から取得
id id id id id id id id
is_private
created_at
older newer older newer
MySQLのOFFSET処理
id title user... . id title user ... . id title user ... . id title user ... .
id title user ... . id title user ... . id title user ... . id title user ... .
id title user ... . id title user ... . id title user ... . id title user ... .
id title user ... .
id title user ... . id title user ... . id title user ... . id title user ... .
id title user ... .
1 2 3 4
5 6 7 8
9 10 11 12
13
10000
10001 10002 10003 10004
81.
MySQLのOFFSET処理
id title user... . id title user ... . id title user ... . id title user ... .
id title user ... . id title user ... . id title user ... . id title user ... .
id title user ... . id title user ... . id title user ... . id title user ... .
id title user ... .
id title user ... . id title user ... . id title user ... . id title user ... .
id title user ... .
1 2 3 4
5 6 7 8
9 10 11 12
13
10000
10001 10002 10003 10004
頑張ってソート
必要な個数まで到達
82.
MySQLのOFFSET処理
id title user... . id title user ... . id title user ... . id title user ... .
id title user ... . id title user ... . id title user ... . id title user ... .
id title user ... . id title user ... . id title user ... . id title user ... .
id title user ... .
id title user ... . id title user ... . id title user ... . id title user ... .
id title user ... .
1 2 3 4
5 6 7 8
9 10 11 12
13
10000
10001 10002 10003 10004
頑張ってソート
必要な個数まで到達
廃棄