Query Sniper

This project is a simple daemon that watches MySQL databases and detects long running queries; any that are found will be killed.

Development

Devcontainer

1. When prompted by vscode or intellij relaunch the project in the devcontainer.

This will use the docker compose file with an overlay to start a primary database, database replica, generate tls certificates, and a development container. The development container shares the same network as the database instances and can be used to develop, test, build, and run query-sniper.

When using the devcontainer the db replica bootstrap script is automatically run to establish mysql replication.

Docker Compose

Start the local mysql cluster:

1. docker compose down -v && docker compose up -d
2. docker compose exec -it app /workspace/.devcontainer/bin/bootstrap.sh

The docker compose file starts up a primary and secondary mysql instance with GTID replication configured. The bootstrap.sh file then:

1. On the primary server, sets the test user up with replication premissions and creates a sample table in the test schema
2. On the replica server, configures replication from the primary, and starts the replication process

Once the bootstrap script is run, you should be able to see the test.config table on the replica server.

MVP

1. ✅ Watch multiple databases at a time
2. ✅ Configurable via config files (one for config, one for database auth creds)
3. Logging when a connection is killed
   • We might also want to include the digest of said connection, if we can strip out the PII

Long term

1. Post to slack when a query is detected and killed
2. Pagerduty alert when a query is detected and killed

References

• The percona toolkit tool pt-kill; it's 9000000 lines of perl and way more than we need here
• mqs a simple query sniper; it hasn't been updated in 8 years
• go-kill-mysql-query TUI tool to interactively kill queries; it's neat, but we want our process to be automated