MySQL Capture

A simple tool for capturing MySQL/MariaDB state information at regular intervals. Useful for troubleshooting performance issues or investigating incidents after the fact.

What it does

Connects to your MySQL database and continuously captures three things:

• Process list
• InnoDB engine status
• Global status variables

Everything gets written to compressed, hourly-rotated log files organized by date.

Database Permissions

Your database user needs the PROCESS and SUPER privileges:

GRANT PROCESS, SUPER ON *.* TO 'monitor'@'localhost';

Quick Start

Run:

# Connect and start capturing (default: 5 second intervals)
./capture --username monitor --ask-pass

# Specify output directory and interval
./capture --username monitor --password secret --path ./logs --interval 10s

Press Ctrl+C to stop.

Connection Options

Connect via TCP:

./capture --hostname 192.168.1.100 --port 3306 --username monitor --password secret

Connect via Unix socket (default for localhost):

./capture --username monitor --ask-pass

Use a MySQL config file:

./capture --defaults-file ~/.my.cnf

Output

Files are organized like this:

logs/
└── 20260216/
    ├── innodb-status.20260216T1500.gz
    ├── processlist.20260216T1500.gz
    └── global-status.20260216T1500.gz

Each file contains timestamped snapshots that you can analyze later:

zcat logs/20260216/processlist.*.gz | grep "SELECT"