d1-cost-optimizer

name	d1-cost-optimizer
description	Cloudflare D1 database cost optimization expert. Analyzes SQL query Row Reads consumption, identifies cost explosion risks, and provides index optimization, query rewriting, and denormalization strategies. Trigger when user mentions D1, Row Reads, query optimization, or database cost.
when_to_use	- User asks about D1 database costs - User needs to optimize SQL queries to reduce Row Reads - User encounters D1 cost overages - User needs to analyze EXPLAIN QUERY PLAN results - User needs to design D1 table structure and indexes
allowed-tools	Bash(wrangler *)

Cloudflare D1 Cost Optimization Expert

Core Principle

D1 billing is based on Row Reads (rows scanned), not rows returned. Cost explosion typically comes from uncontrolled Row Reads.

Common Anti-Patterns

Anti-Pattern	Problem	Reference
Missing indexes	Full table scans	references/unindexed-join.md
Deep OFFSET	Scans discarded rows	references/deep-pagination.md
SELECT *	Fetches unnecessary data	references/select-star-all.md
Full table scan