01-pessimistic-locking

README

Pessimitic Locking in GO

Running the following code on threads will give you inconsistent results.

func incCount(){
	count++;
	wg.Done()
}

func doCount(){
	for i:=0; i < 1000000; i++{
		wg.Add(1)
		go incCount()
	}
}

Reason:
Count++ (increment operation) is not atomic in nature. Micro-operations in registers

1. movl %rdi, %tmp LOAD
2. addl $1, %tmp ADD
3. movl %tmp, %rdi STORE

Solution:
Lock and Unlock the operation (count++) using Mutex, so that only one thread runs the operation at a time.

var mu sync.Mutex

mu.Lock()
count++;
mu.Unlock()

Reference:

Pessimitic Locking with Mutex