postgres-patterns

name postgres-patterns description PostgreSQL database patterns for query optimization, schema design, indexing, and security. Based on Supabase best practices. Use when designing PostgreSQL schemas, indexes, or RLS policies, or when a query is too slow. metadata {"origin":"ECC"} PostgreSQL Patterns Quick reference for PostgreSQL best practices. For detailed guidance, use the database-reviewer agent. When to Activate Writing SQL queries or migrations Designing database schemas Troubleshooting slow queries Implementing Row Level Security Setting up connection pooling Quick Reference Index Cheat Sheet Query Pattern Index Type Example WHERE col = value B-tree (default) CREATE INDEX idx ON t (col) WHERE col > value B-tree CREATE INDEX idx ON t (col) WHERE a = x AND b > y Composite CREATE INDEX idx ON t (a, b) WHERE jsonb @> '{}' GIN CREATE INDEX idx ON t USING gin (col) WHERE tsv @@ query GIN CREATE INDEX idx ON t USING gin (col) Time-series ranges BRIN CREATE INDEX idx ON t USING brin (col) Data Type Quick Reference Use Case Correct Type Avoid IDs bigint int , random UUID Strings text varchar(255) Timestamps timestamptz timestamp Money numeric(10,2) float Flags boolean varchar , int Common Patterns Composite Index Order: -- Equality columns first, then range columns CREATE INDEX idx ON orders (status, created_at); -- Works for: WHERE status = 'pending' AND created_at > '2024-01-01' Covering Index: CREATE INDEX idx ON users (email) INCLUDE (name, created_at); -- Avoids table lookup for SELECT email, name, created_at Partial Index: CREATE INDEX idx ON users (email) WHERE deleted_at IS NULL ; -- Smaller index, only includes active users RLS Policy (Optimized): CREATE POLICY policy ON orders USING (( SELECT auth.uid()) = user_id); -- Wrap in SELECT! UPSERT: INSERT INTO settings (user_id, key, value ) VALUES ( 123 , 'theme' , 'dark' ) ON CONFLICT (user_id, key) DO UPDATE SET value = EXCLUDED.value; Cursor Pagination: SELECT * FROM products WHERE id > $last_id ORDER BY id LIMIT 20 ; -- O(1) vs OFFSET which is O(n) Queue Processing: UPDATE jobs SET status = 'processing' WHERE id = ( SELECT id FROM jobs WHERE status = 'pending' ORDER BY created_at LIMIT 1 FOR UPDATE SKIP LOCKED ) RETURNING * ; Anti-Pattern Detection -- Find unindexed foreign keys SELECT conrelid::regclass, a.attname FROM pg_constraint c JOIN pg_attribute a ON a.attrelid = c.conrelid AND a.attnum = ANY (c.conkey) WHERE c.contype = 'f' AND NOT EXISTS ( SELECT 1 FROM pg_index i WHERE i.indrelid = c.conrelid AND a.attnum = ANY (i.indkey) ); -- Find slow queries SELECT query, mean_exec_time, calls FROM pg_stat_statements WHERE mean_exec_time > 100 ORDER BY mean_exec_time DESC ; -- Check table bloat SELECT relname, n_dead_tup, last_vacuum FROM pg_stat_user_tables WHERE n_dead_tup > 1000 ORDER BY n_dead_tup DESC ; Configuration Template -- Connection limits (adjust for RAM) ALTER SYSTEM SET max_connections = 100 ; ALTER SYSTEM SET work_mem = '8MB' ; -- Timeouts ALTER SYSTEM SET idle_in_transaction_session_timeout = '30s' ; ALTER SYSTEM SET statement_timeout = '30s' ; -- Monitoring CREATE EXTENSION IF NOT EXISTS pg_stat_statements; -- Security defaults REVOKE ALL ON SCHEMA public FROM public; SELECT pg_reload_conf(); Related Agent: database-reviewer - Full database review workflow Skill: clickhouse-io - ClickHouse analytics patterns Skill: backend-patterns - API and backend patterns Based on Supabase Agent Skills (credit: Supabase team) (MIT License)