Skylight

Lawrence：發現繼續賴著用免費的 Scout 也不是辦法，因為目前沒有 N+1 的 tracing 可看，要優化報表 worker 也要有一些 tracing 參考才不會不小心優化過頭（i.e. 全部都很快但很醜的 SQL 重構，但也許其實只需要修掉幾個 N+1 query）。

看了一下各家 APM，已能夠精細追到 N+1 query 的 ruby code stacktrace 除了目前賴著用的 Scout 以外，AppSignal 也是用 request 數算錢，Skylight 更是因為無法設定 billing 上限已經列為拒絕往來戶。

目前找到 New Relic 是用機器數計費比較適合我們，平均 5 dyno 是 $99/mo 而平均 8 dyno 是 $159/mo，相較於前者們都便宜很多，Samuel 如果沒有什麼 concern 我就開一下 14 day trial 囉～？或是如果有人知道其他我漏掉的 APM 也歡迎提供～。

雖然 UI 跟舊版 Google Analytics 有得比（？），但 Rails 相關指標看起來比 Scout 還細，以後 tune performance 應該會很有幫助。

We currently monitor performance with the following tools:

1. Heroku Metrics: our main app is Hosted on Heroku, so it is the best place to get quick server metrics like memory usage, load averages, or response times.
2. Good old New Relic for detailed general metrics, including transaction times.
3. Skylight for more specific Rails Controller#action transaction times. Navigating those timings is much better than with New Relic, as you get a clear full breakdown of everything that happens for a given request.

Skylight offers better Rails performance insights, so why use New Relic? Because it does frontend monitoring, while Skylight doesn't. Now that we have a separate frontend app though, our frontend engineers are looking into more specialized frontend monitoring solutions.

Finally, if one of our apps go down, Pingdom alerts us on Slack and texts some of us.

An essential for determining production performance. It provides us with clear insights into what might be slowing down responses so we know exactly what to fix. Skylight