slowql-replayer

slowql-replayer

A tool to replay queries from a slow query log file.

Installation

There is multiple ways to get slowql-replayer.

By using go install

$ go install github.com/devops-works/slowql/cmd/slowql-replayer

By cloning the repo and building it

$ git clone https://github.com/devops-works/slowql
$ cd slowql/
$ make replayer

A binary called replayer will be created at the root of the repo, under bin/.

(go is required!)

By downloading the pre-built binary

You can find the latest version in the releases

Usage

Usage of replayer:
  -db string
        Name of the database to use
  -f string
        Slow query log file to use
  -h string
        Addres of the database, with IP and port
  -hide-progress
        Hide progress bar while replaying
  -k string
        Kind of the database (mysql, mariadb...)
  -l string
        Logging level (default "info")
  -no-dry-run
        Replay the requests on the database for real
  -p    Use a password to connect to database
  -pprof string
        pprof server address
  -show-errors
        Show SQL errors when they occur
  -u string
        User to use to connect to database
  -w int
        Number of maximum simultaneous connections to database (default 100)
  -x float
        Speed factor (default 1)

A typical example might be:

$ ./replayer -u ezekiel -p -h 192.168.1.2:3306 -k mysql -f ~/files/databases/log/mysql.log -db mydb

By adding -no-dry-run, it will send the queries to the database for real.

At the end, a short report is displayed:

=-= Results =-=

Replay duration:  49.330633992s
Real duration:    49.327466s
Log file:         /home/ezekiel/files/databases/log/mysql.log
Dry run:          false
Workers:          100

Database
  ├─ kind:      mysql
  ├─ user:      ezekiel
  ├─ use pass:  true
  └─ address:   192.168.1.2:3306

Statistics
  ├─ Queries:                90004
  ├─ Errors:                 2
  ├─ Queries success rate:   99.9978%
  ├─ Speed factor:           1.0000
  ├─ Duration difference:    replayer took 3.167992ms more
  └─ Replayer speed:         -0.0064%

Docker

The file Dockerfile.replayer allows you to build the Docker image of replayer:

$ docker build -f Dockerfile.replayer -t dw/replayer .

By default, replayer looks for file called slowquery.log at /log. So you can provide the file by sharing it via a volume, and then give the arguments:

$ docker run --rm -it -v /path/to/slowquery/file/local-slowquery.log:/log/slowquery.log  dw/replayer [OPTIONS (without -f)]

NOTE: don't forget to add the option -it if you want to use a password !

Adjustments

Speed

You can also adjust a speed factor with the option -x which can receive a float. For example, if you set the speed factor to 2, it will replay the queries twice as fast. On the ortherhand, if you set it to 0.5, it will replay twice as slow.

Concurrency

Also, you can specify the number of workers that will request the database is simultaneously with -w. This way, you can simulate concurrency. The default value is 100.

Progress bar

If the progress bar bothers you, you can hide it with -hide-progress.

Databases kinds

The following table shows all the accepted values for -k

Supported databases

We successfully tested replayer on:

• MySQL
• MariaDB
• Percona-db
• Percona-cluster

Note: slowql-replayer relies heavily on the slowql package, so if a database is missing in the package, it will not be present in the replayer.

License

MIT