Golang Tips
Go Programming Patterns: Slices, Interfaces, Time, and Performance Go is a high-performance language, but that does not mean we can ignore performance. Here are some tips related to programming and performance.
If you need to convert numbers to strings, strconv.Itoa() is about twice as fast as fmt.Sprintf(). Avoid converting String to []Byte where possible. This conversion hurts performance. If you use append() on a slice inside a for-loop, expand the slice capacity ahead of time to avoid reallocations and automatic growth by powers of two, which can waste memory. Use StringBuffer or StringBuild to concatenate strings; they are three to four orders of magnitude faster than + or +=. Use concurrent goroutines where possible, and use sync.WaitGroup to synchronize concurrent work. Avoid allocating in hot paths; it makes the GC busy. Use sync.Pool to reuse objects. Use lock-free operations and avoid mutexes when possible; use sync/Atomic. (See Lock-Free Queue Implementation or Lock-Free Hashmap Implementation.) Use I/O buffering; I/O is very slow. bufio.NewWrite() and bufio.NewReader() improve performance. For fixed regex patterns in a for-loop, use regexp.Compile() to precompile; it improves performance by two orders of magnitude. If you need higher-performance protocols, consider protobuf or msgp instead of JSON, because JSON serialization/deserialization uses reflection. When using maps, integer keys are faster than string keys because integer comparisons are faster.
