MySQL Database

Authentication

IMPORTANT: Credentials are injected automatically by a proxy layer. Do NOT check for MYSQL_PASSWORD in environment variables - it won't be visible to you. Just run the scripts directly; authentication is handled transparently.

Configuration environment variables you CAN check (non-secret):

• MYSQL_HOST

• Database host

• MYSQL_PORT

• Database port (default: 3306)

• MYSQL_DATABASE

• Database name

MANDATORY: Schema-First Investigation

Understand the schema before running queries.

LIST TABLES → DESCRIBE TABLE → EXECUTE QUERY → CHECK HEALTH

Available Scripts

All scripts are in .claude/skills/database-mysql/scripts/

list_tables.py - List Tables (START HERE)

python .claude/skills/database-mysql/scripts/list_tables.py [--database DB]

describe_table.py - Table Schema Details

python .claude/skills/database-mysql/scripts/describe_table.py --table TABLE_NAME [--database DB]

execute_query.py - Run SQL Queries

python .claude/skills/database-mysql/scripts/execute_query.py --query "SELECT * FROM users LIMIT 10" [--limit 100]

show_processlist.py - Active Connections

python .claude/skills/database-mysql/scripts/show_processlist.py [--full]

show_replica_status.py - Replication Health

python .claude/skills/database-mysql/scripts/show_replica_status.py

show_engine_status.py - InnoDB Engine Status

python .claude/skills/database-mysql/scripts/show_engine_status.py [--engine innodb]

get_table_locks.py - Lock Contention

python .claude/skills/database-mysql/scripts/get_table_locks.py

Investigation Workflow

Slow Query Investigation

1. show_processlist.py --full (find active/long queries)
2. show_engine_status.py (check InnoDB lock waits, deadlocks)
3. get_table_locks.py (find lock contention)

Replication Lag

1. show_replica_status.py (check Seconds_Behind_Master)
2. show_processlist.py (check for blocking queries)