RDS Parameter Groups and Monitoring

RDS Parameter Groups and Monitoring

Beyond launching an RDS instance, Solutions Architects must know how to configure database engine parameters, monitor performance, and troubleshoot issues using native AWS tools.

Parameter Groups — Database Configuration

Parameter Groups contain database engine settings (like MySQL my.cnf or PostgreSQL postgresql.conf). You cannot directly SSH into RDS and edit config files — instead, you modify parameter groups.

# Common parameters (MySQL)
max_connections = 200           # Maximum concurrent connections
innodb_buffer_pool_size = 80%   # Memory for InnoDB cache
slow_query_log = 1              # Enable slow query logging
long_query_time = 2             # Log queries taking >2 seconds
character_set_server = utf8mb4  # Character encoding

# Some parameters require reboot (static)
# Others apply immediately (dynamic)
# Check parameter type before changing production!

RDS Performance Insights

Performance Insights is the most powerful RDS monitoring tool — it shows a real-time and historical view of database load, broken down by SQL query, wait event, user, and host.

• DB Load: how many active sessions are querying the database at any moment
• Top SQL: which queries consume the most time
• Wait events: what are queries waiting for? (CPU, I/O, lock wait)
• Free for most instance types, enables detection of slow queries instantly

Enhanced Monitoring

Enhanced Monitoring provides OS-level metrics (CPU, memory, disk I/O) at 1-second granularity from inside the DB instance — standard CloudWatch metrics are only 1-minute intervals.

RDS Event Subscriptions

# Get notified about RDS events
# Events: instance failure, failover, storage full, backup complete
aws rds create-event-subscription 
  --subscription-name my-rds-alerts 
  --sns-topic-arn arn:aws:sns:...:rds-alerts 
  --source-type db-instance 
  --event-categories failover backup notification