For anyone running MySQL on an m7i.24xlarge instance, what value do you get from `SHOW GLOBAL VARIABLES LIKE 'max_connections';`? Mine consistently returns 16,000, and I'm trying to determine whether that is the expected instance-based default or if something is configured incorrectly.
3 Answers
Hopefully you’re already using connection pooling or a database proxy. Managing thousands of direct client connections can consume significant resources, even if the configured maximum is much higher.
That value is based on the instance size by default, but it can be changed through database parameters or other configuration settings. Raising the limit isn’t automatically harmless, though—the right value depends on your workload and available resources. If you’re creating lots of short-lived connections, performance may start degrading somewhere around 22,000–24,000 connections, so a connection pool or proxy is generally important at that scale.
The service documentation lists the max-connections limits, and the published guidance explains how MySQL calculates the setting. For this instance size, roughly 192 GB of memory divided by the per-connection allocation produces a limit of about 16,000, which matches what you’re seeing.
The 16,000 figure also lines up with the instance’s memory-based calculation, so it sounds like the expected default rather than a misconfiguration.