Reads Postgres EXPLAIN and EXPLAIN ANALYZE plans (text or JSON) and finds why a query is slow - sequential scans on large relations, nested loops with huge row estimates, misestimates (estimated vs actual), high buffer reads, Sort/Hash that spill to disk, missing LIMIT pushdown and expensive nodes by actual time. Ranks fixes (index, rewrite, stats). Offline stdlib Python analyzer.
Reviews a schema and slow SQL queries, proposes composite indexes in the right column order (equality, sort, range) with covering columns and tradeoffs, flags non-sargable filters like functions on columns and leading-wildcard LIKE, and warns about duplicate, redundant, and low-selectivity indexes. Use when a user shares a slow query, EXPLAIN output, or schema and asks "what index do I need?" or "too many indexes?". Includes a tested stdlib Python helper.
Reviews SQL queries and optional EXPLAIN output for common performance problems such as SELECT *, functions or casts on indexed columns, leading-wildcard LIKE, N+1 query loops, OR across columns vs UNION ALL, AND/OR precedence slips, NOT IN subqueries, deep OFFSET paging, seq scans and disk sorts. Explains each problem and gives a rewritten query. Includes a stdlib Python checker with --self-test.
Reviews PostgreSQL and MySQL tables (schema.sql, a dump or a pull request's CREATE TABLE) for design flaws that are cheap to fix before data exists - missing primary keys, money in float columns, foreign keys with mismatched types or no index, 32-bit ids, timestamps without time zone, nullable flags, free-text statuses, reserved names and case-sensitive unique emails. Returns corrected DDL. Includes a stdlib Python linter with --self-test.
Sizes database connection pools for Postgres/MySQL apps from a short JSON of services, pods, workers, threads and pool settings - worst-case connections at autoscale max and during deploy surges vs max_connections, busy connections from rps x hold time, per-process wait odds (Erlang C), CPU and memory limits, PgBouncer client and server limits. Recommends pool sizes or proxy settings. Includes an offline stdlib Python calculator with --self-test.
Finds out why your CI builds are slow: tracks job times over weeks, spots missing caches, serial steps and oversized runners, and suggests concrete changes ranked by minutes saved.
Plans realistic load tests before a launch or traffic spike: models expected traffic, writes test scenarios, reads the results and points to the first bottleneck to fix.
Plans safe API call budgets across services and environments: maps quotas and burst limits, sizes caches and queues, and spots which jobs will trip 429s before they hit production.
