Postgres Patterns

vibeeval/postgres-patterns

PostgreSQL database patterns for query optimization, schema design, indexing, and security. Based on Supabase best practices.

990 tokens

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the whole folder, loaded on every use

files

instructions only

copies elsewhere

how many repositories repackaged it

521

stars on the repo

on the repository, not the skill itself

Install

one command, takes just this skill from the repository

npx skills add https://github.com/vibeeval/vibecosystem --skill postgres-patterns

The instruction itself

9 sections, as written by the author

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();

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 (MIT License)*

How to use it

Copy the folder

Take vibeeval/postgres-patterns from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

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