191 Configuration A2515b4c

Analytics Engine Configuration

Setup

1. Add binding to wrangler.jsonc
2. Deploy Worker
3. Dataset created automatically on first write
4. Query via SQL API

wrangler.jsonc

{
  "name": "my-worker",
  "analytics_engine_datasets": [{ "binding": "ANALYTICS", "dataset": "my_events" }],
}

Multiple datasets for separate concerns:

{
  "analytics_engine_datasets": [
    { "binding": "API_ANALYTICS", "dataset": "api_requests" },
    { "binding": "USER_EVENTS", "dataset": "user_activity" },
  ],
}

TypeScript

interface Env {
  ANALYTICS: AnalyticsEngineDataset
}

export default {
  async fetch(request: Request, env: Env) {
    // No await - returns void, fire-and-forget
    env.ANALYTICS.writeDataPoint({
      blobs: [pathname, method, status], // String dimensions (max 20)
      doubles: [latency, 1], // Numeric metrics (max 20)
      indexes: [apiKey], // High-cardinality filter (max 1)
    })
    return response
  },
}

Data Point Limits

Write Behavior

Mitigate sampling: Pre-aggregate, use multiple datasets, write only critical metrics.

Query Limits

Cost

Free tier: 10M writes/month, 1M reads/month

Paid: $0.05 per 1M writes, $1.00 per 1M reads

Environment-Specific

{
  "analytics_engine_datasets": [{ "binding": "ANALYTICS", "dataset": "prod_events" }],
  "env": {
    "staging": {
      "analytics_engine_datasets": [{ "binding": "ANALYTICS", "dataset": "staging_events" }],
    },
  },
}

Monitoring

npx wrangler tail  # Check for sampling/write errors

-- Check write activity
SELECT DATE_TRUNC('hour', timestamp) AS hour, COUNT(*) AS writes
FROM my_dataset
WHERE timestamp >= NOW() - INTERVAL '24' HOUR
GROUP BY hour