RDS的最大連線數限制

RDS的機臺分很多型，
RAM、硬碟速度都不同，
一位外國網友列出了他的測試數據︰

Max. Connections on RDS MySQL

Just recently I ran into some MySQL issues while load-testing our web servers. The reason were limitations in the predefined MySQL RDS settings for our RDS instance plus some swapping lags due to missing RAM on heavy operations. The CPU was always at less than 30%.
I fixed both issues in upgrading from a small RDS instance (1.7 GB RAM) to a large RDS instance (7,5 GB RAM).
The predefined AWS RDS settings for MySQL max. connections are:

• Small Instance: 150 connections
• Large instance: 640 connections

他測出一個samll型的RDS(1.7 GB RAM)，大概可以忍受150人同時連線，
而large型的RDS(7.5 GB RAM)則能忍受640個連線數。
我自己使用的經驗，如果是提供的AWS Free Usage Tiermicro型RDS，只能提供33人同時連線。
悲劇。