29回勉強会資料「PostgreSQLのリカバリ超入門」
See also http://www.interdb.jp/pgsql (Coming soon!)
初心者向け。PostgreSQLのWAL、CHECKPOINT、 オンラインバックアップの仕組み解説。
これを見たら、次は→ http://www.slideshare.net/satock/29shikumi-backup
29回勉強会資料「PostgreSQLのリカバリ超入門」
See also http://www.interdb.jp/pgsql (Coming soon!)
初心者向け。PostgreSQLのWAL、CHECKPOINT、 オンラインバックアップの仕組み解説。
これを見たら、次は→ http://www.slideshare.net/satock/29shikumi-backup
IoT Devices Compliant with JC-STAR Using Linux as a Container OSTomohiro Saneyoshi
Security requirements for IoT devices are becoming more defined, as seen with the EU Cyber Resilience Act and Japan’s JC-STAR.
It's common for IoT devices to run Linux as their operating system. However, adopting general-purpose Linux distributions like Ubuntu or Debian, or Yocto-based Linux, presents certain difficulties. This article outlines those difficulties.
It also, it highlights the security benefits of using a Linux-based container OS and explains how to adopt it with JC-STAR, using the "Armadillo Base OS" as an example.
Feb.25.2025@JAWS-UG IoT
137. 他にもたとえば
コメント数の多いユーザー10⼈を抽出するクエリー
SELECT user.user_name,
COUNT(*) AS comment_count
FROM user JOIN comment ON user.user_name = comment.comment_owner
GROUP BY user.user_name
ORDER BY comment_count DESC LIMIT 10
commentテーブルの結合のためにidx̲commentowner
(comment̲owner)
userテーブルのGROUP BYのためにuser̲nameはプライマリーキーなの
でこのままでOK
ORDER BYのcomment̲countは集計関数の結果カラムなのでソートは
避けられない
5.6以降ならばソート⽤の⼀時インデックスを⾃動で作るかも。-
136/144