Database Observability: tracking MySQL and PostgreSQL queries and plans with Alloy

1. Beyond server metrics #

What Database Observability sees.

The principle #

A Prometheus exporter says the database is slow; Database Observability says which query, with which execution plan and which locks. The database_observability.mysql and database_observability.postgres components collect these details and send them to Loki; the Grafana Cloud Database Observability app presents them.

MySQL collectors #

2. The configuration #

MySQL to Loki and Mimir.

config.alloy #

local.file "mysql_dsn" {
  filename  = "/etc/alloy/secrets/mysql-dsn"
  is_secret = true
}

prometheus.exporter.mysql "orders" {
  data_source_name = local.file.mysql_dsn.content
}

database_observability.mysql "orders" {
  data_source_name  = local.file.mysql_dsn.content
  forward_to        = [loki.write.default.receiver]
  targets           = prometheus.exporter.mysql.orders.targets
  enable_collectors = ["locks", "table_stats"]
}

prometheus.scrape "orders" {
  targets    = database_observability.mysql.orders.targets
  forward_to = [prometheus.remote_write.mimir.receiver]
}

loki.write "default" {
  endpoint {
    url = "http://loki:3100/loki/api/v1/push"
  }
}

prometheus.remote_write "mimir" {
  endpoint {
    url = "http://mimir:9009/api/v1/push"
  }
}

Configuration validated with alloy validate (Alloy v1.21.3, November 2026).

• The DSN is a secret: read by local.file with is_secret = true, it does not appear in the Alloy UI or logs.
• targets: reuses those of prometheus.exporter.mysql to link details and metrics of the same instance.
• allow_update_performance_schema_settings (false by default): needed for query_samples and setup_actors to adjust performance_schema themselves.

Database side #

Create a dedicated read-only user with access to performance_schema (MySQL) or pg_stat_statements and pg_monitor (PostgreSQL). Exact grants depend on the version: follow Grafana's setup guide for your engine.

Not run here: without a MySQL server in our environment, the configuration was validated, not run.

Sources #

• Grafana Alloy : database_observability.mysql
• Grafana Alloy : database_observability.postgres