Misframe

MySQL slow query log parser Go package

Published Dec 26, 2017

tl;dr: Simple, MIT-licensed, available on GitHub: https://github.com/Preetam/mysqllog


I couldn’t find a simple slow query log parser in Go so I decided to write one. The two I found are:

I don’t like how those packages use channels. There’s just too much plumbing required when you have an input channel and an output channel, or a stop channel. With my package you just need to create a parser and feed it slow query log data line-by-line. (I think channels are overused in some Go programs but that’s a separate discussion.)

Example usage

I included a small program in the mysqllog package to read a MySQL slow query log from stdin and print the events as JSON objects to stdout.

This is what it looks like right now:

package main

import (
	"bufio"
	"encoding/json"
	"fmt"
	"os"

	"github.com/Preetam/mysqllog"
)

func main() {
	p := &mysqllog.Parser{}

	reader := bufio.NewReader(os.Stdin)
	for line, err := reader.ReadString('\n'); err == nil; line, err = reader.ReadString('\n') {
		event := p.ConsumeLine(line)
		if event != nil {
			b, _ := json.Marshal(event)
			fmt.Printf("%s\n", b)
		}
	}
}

To use that, I first spun up an RDS instance and used Honeycomb’s rdslogs tool to get the slow query log data from my instance to stdout. Then I just piped that to my program. Works great, and only took a couple of hours or so!

I only tested it with MySQL 5.7 on RDS. It doesn’t support older formats of the slow query log. I will accept patches if you have them!