How to Avoid Common Performance Pitfalls in Go

Avoid Go performance pitfalls by controlling runtime behavior with GODEBUG settings and optimizing standard library usage like HTTP connection reuse. Set specific flags via the GODEBUG environment variable or //go:debug directives to disable expensive features or revert to older, faster behaviors when necessary.

export GODEBUG=http2client=0,http2server=0

For HTTP performance, ensure Transport.MaxIdleConns is set to a positive integer to enable connection reuse, or set Transport.DisableKeepAlives to true if reuse causes degradation in your specific workload.

Go performance issues often stem from default behaviors that are safe but slow, like automatic HTTP/2 negotiation or excessive connection handling. You can fix this by flipping specific switches called GODEBUG to turn off these features or by configuring your HTTP client to reuse connections properly. Think of it like turning off a car's automatic cruise control when you need to drive faster on a winding road.