Postgres Best Practices

Iron Law

NEVER TUNE WHAT YOU HAVEN'T MEASURED — CHECK pg_stat_statements AND pg_stat_activity BEFORE CHANGING CONFIGURATION OR ADDING INDEXES

When to Use This Skill

• Configuring connection pooling (PgBouncer, Prisma pool, asyncpg pool, R2DBC pool)
• Implementing Row Level Security (RLS) for multi-tenant data isolation
• Designing worker queues with SKIP LOCKED and advisory locks
• Preventing deadlocks in concurrent write workloads
• Configuring VACUUM/ANALYZE and autovacuum tuning
• Adding full-text search with tsvector/tsquery
• Indexing JSONB columns (jsonb_ops vs jsonb_path_ops)
• Reviewing any PostgreSQL schema or query against the 8-category rule library

Do Not Use This Skill When

• You need query EXPLAIN analysis and index pattern SQL (use sql-optimization-patterns)
• You need schema migration design or ERDs (use database-schema-designer)
• You need cloud analytics or HTAP (use sql-pro)

Rule Categories by Priority

Quick Rule Index

Connection Management (NEW — not in other skills)

• rules/conn-pooling.md — PgBouncer setup, pool size formula (cores × 2) + spindles, transaction vs session mode
• rules/conn-limits.md — max_connections calculation, prevent database OOM crash
• rules/conn-idle-timeout.md — Reclaim 30-50% idle connection slots
• rules/conn-prepared-statements.md — Prepared statement conflicts in transaction-mode pooling

Concurrency & Locking (NEW — not in other skills)

• rules/lock-skip-locked.md — Atomic claim-and-update queue pattern, 10x worker throughput
• rules/lock-deadlock-prevention.md — Consistent lock ordering, deadlock prevention patterns
• rules/lock-short-transactions.md — Minimize transaction duration, 3-5x throughput
• rules/lock-advisory.md — Application-level coordination without row-level locks

Security & RLS (NEW depth — not in other skills)

• rules/security-rls-basics.md — ALTER TABLE ... ENABLE ROW LEVEL SECURITY + policy patterns
• rules/security-rls-performance.md — SECURITY DEFINER functions, 5-10x faster RLS queries
• rules/security-privileges.md — Principle of least privilege, specific GRANT patterns

Monitoring & Maintenance (NEW — not in other skills)

• rules/monitor-vacuum-analyze.md — VACUUM/ANALYZE patterns, autovacuum tuning
• rules/monitor-pg-stat-statements.md — Enable and query pg_stat_statements
• rules/monitor-explain-analyze.md — EXPLAIN ANALYZE usage guide

Advanced Features (NEW — not in other skills)

• rules/advanced-full-text-search.md — tsvector, ts_rank, GIN full-text index, 100x vs LIKE
• rules/advanced-jsonb-indexing.md — GIN index, jsonb_ops vs jsonb_path_ops trade-off

Query Performance (complementary to sql-optimization-patterns)

• rules/query-missing-indexes.md — EXPLAIN Seq Scan detection
• rules/query-index-types.md — B-tree/GIN/BRIN/Hash selection
• rules/query-composite-indexes.md — Leftmost prefix rule
• rules/query-covering-indexes.md — INCLUDE columns for Index Only Scan
• rules/query-partial-indexes.md — Filtered index subsets

Schema Design (complementary to database-schema-designer)

• rules/schema-primary-keys.md — IDENTITY vs UUID vs UUIDv7
• rules/schema-data-types.md — Forbidden types, correct alternatives
• rules/schema-foreign-key-indexes.md — Diagnostic SQL to find all missing FK indexes
• rules/schema-lowercase-identifiers.md — snake_case, no quoted identifiers
• rules/schema-partitioning.md — Range partitioning patterns
• rules/schema-foreign-key-indexes.md — FK index enforcement

Stack Integration

Python / FastAPI (asyncpg + SQLAlchemy)

• Connection pooling: asyncpg pool min_size/max_size configuration (see rules/conn-pooling.md)
• RLS: set app.current_user_id session variable before queries
• SKIP LOCKED: use in background task workers

NestJS / Prisma

• Connection pooling: DATABASE_URL=...?connection_limit=10&pool_timeout=20 (see rules/conn-pooling.md)
• Prepared statements: Prisma uses prepared statements — use session mode or pgbouncer=true parameter
• SKIP LOCKED: use prisma.$queryRaw for queue worker queries

Java / Spring Boot WebFlux (R2DBC)

• Connection pooling: r2dbc.pool.max-size, r2dbc.pool.initial-size (see rules/conn-pooling.md)
• RLS: use ConnectionFactory with per-request session variable injection

Related Skills

• database-schema-designer — Schema design, Flyway migrations, normalization
• sql-optimization-patterns — EXPLAIN analysis, N+1, cursor pagination, batch ops
• postgresql — PostgreSQL-specific types, gotchas, extensions, JSONB depth
• sql-pro — Cloud analytics, HTAP, BigQuery/Snowflake
• vector-database — pgvector HNSW/IVFFlat alignment