Monitoring and Metrics - Fly.io

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Performance Monitoring

The Managed Postgres dashboard provides comprehensive performance monitoring and metrics for your PostgreSQL clusters. The Metrics tab gives you real-time visibility into your database’s performance, helping you identify bottlenecks and optimize your applications.

Accessing Metrics

To view metrics for your cluster:

Navigate to your MPG cluster in the Fly.io dashboard
Click the Metrics tab
Optionally filter by specific database using the database dropdown
Select your desired time range (15 minutes, 1 hour, 6 hours, 24 hours, or 2 days)

Available Charts and Metrics

The metrics dashboard provides detailed insights through various charts and gauges organized into categories:

System Resource Metrics

Metric	Description
Database CPU Utilization	CPU usage percentage for each database instance, labeled with Primary (P) and Replica (R) badges. Shows individual instance IDs and averages over the selected time period
Database Memory Utilization	Memory usage for Primary and Replica database instances. Displays current usage and average consumption per instance
Pooler CPU Utilization	CPU usage percentage for PGBouncer connection pooler instances. Typically remains low under normal operations
Pooler Memory Utilization	Memory consumption in MB for connection pooler instances. Shows usage for each pooler with instance IDs

Connection Metrics

Metric	Description
Database Connections	Shows active and idle database connections over time
Pooler Connections	Tracks active and waiting connections through PGBouncer

Database Operations

Metric	Description
Database Operations	Row-level operations per second broken down by type (inserts, updates, deletes, and fetches). Shows throughput patterns and workload distribution across operation types
Cache Hit Ratio	Percentage of data requests served from memory versus disk. Higher percentages (95%+) indicate efficient memory usage. Lower values suggest queries are hitting disk frequently
Deadlocks	Count of database deadlocks detected when two or more transactions are waiting for each other to release locks. Shows frequency and timing of these mutual blocking situations

Storage

Metric	Description
Database Size	Current storage usage across databases

Replication Metrics

Metric	Description
Replication Delay Bytes	Amount of WAL (Write-Ahead Log) data in bytes that the replica is behind the primary. Measures the volume of changes waiting to be applied
Replication Delay Seconds	Time in seconds that the replica lags behind the primary database. Represents how long ago the replica’s current state reflects the primary

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