d1-optimizer

To optimize slow SQLite queries on Cloudflare D1, analyze EXPLAIN QUERY PLAN output to identify bottlenecks, apply tailored composite or partial indexes, and eliminate N+1 queries using batch-fetch patterns.

Handling D1 single-writer mode constraints requires using batch write optimization to group operations, reducing round-trips and ensuring atomicity, while routing read queries to replicas to improve performance.

EXPLAIN QUERY PLAN analysis improves D1 edge performance by revealing how the SQLite engine executes a query, allowing you to identify missing indexes, detect full table scans, and eliminate N+1 query bottlenecks.

You can speed up D1 query performance by implementing read replica patterns that route read queries to replicas, directing writes to the primary database to respect serialized-writes constraints and reduce latency.

Batch writes may fail atomicity if operations are not grouped correctly; D1 requires batch write optimization to reduce round-trips and ensure atomic execution under its serialized-writes edge deployment model.

Common D1 indexing anti-patterns include ignoring composite and partial indexes, failing to eliminate N+1 queries through joins, and overlooking FTS considerations for efficient data access on edge deployments.