# Prometheus alerting rules groups: - name: database rules: # Database down - alert: DatabaseDown expr: pg_up == 0 for: 1m labels: severity: critical annotations: summary: "PostgreSQL down on {{ $labels.instance }}" description: "Database has been down for more than 1 minute" # High connection usage - alert: HighConnectionUsage expr: | pg_stat_activity_count / pg_settings_max_connections * 100 > 80 for: 5m labels: severity: warning annotations: summary: "High connection usage on {{ $labels.instance }}" description: "Connection usage is above 80%" # Replication lag - alert: ReplicationLagHigh expr: | pg_stat_replication_pg_wal_lsn_diff / 1024 / 1024 > 1000 for: 5m labels: severity: warning annotations: summary: "Replication lag high on {{ $labels.instance }}" description: "Replication lag is above 1GB" # Dead tuples high - alert: HighDeadTuples expr: | pg_stat_user_tables_n_dead_tup > 1000000 for: 1h labels: severity: warning annotations: summary: "High dead tuples on {{ $labels.relname }}" description: "Table has over 1M dead tuples" # Slow queries - alert: SlowQueriesIncreasing expr: | rate(pg_stat_statements_total_time_sum[5m]) > 10000 for: 10m labels: severity: warning annotations: summary: "Slow queries increasing" description: "Query execution time is trending up" # Disk space - alert: DiskSpaceLow expr: | pg_database_size_bytes / pg_settings_data_directory_size * 100 > 85 for: 5m labels: severity: critical annotations: summary: "Disk space low on {{ $labels.instance }}" description: "Disk usage is above 85%"

14-monitoring

14 - Monitoring & Observability

Why Monitor Databases?

14-monitoring

14 - Monitoring & Observability

Why Monitor Databases?

Key Metrics

The Four Golden Signals

Database-Specific Metrics

Monitoring Tools

Built-in Tools

External Monitoring Tools

Prometheus + Grafana Setup

Dashboard Design

Key Dashboards

Alerting

Critical Alerts

Log Analysis

PostgreSQL Log Configuration

Common Log Patterns

Performance Insights

Wait Events Analysis

Query Plan Analysis

Next: Choosing the Right Database