firefrost-operations-manual/docs/skills/postgres-patterns/SKILL.md

name, description, source

name	description	source
postgres-patterns	PostgreSQL database patterns for query optimization, schema design, indexing, and security. Use this skill when working on Arbiter's database (arbiter_db), writing migrations, troubleshooting slow queries, or implementing security policies.	skill.fish (affaan-m/everything-claude-code)

PostgreSQL Patterns

Quick reference for PostgreSQL best practices.

---

WHEN TO ACTIVATE

• Writing SQL queries or migrations
• Designing database schemas
• Troubleshooting slow queries
• Implementing Row Level Security
• Setting up connection pooling
• Working on Arbiter's arbiter_db

---

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();

---

FIREFROST CONTEXT

Arbiter Database (arbiter_db)

Location: Command Center (63.143.34.217) User: arbiter Password: (see .env on Command Center)

Current Tables:

• subscriptions — Stripe subscription tracking
• users — Discord user data
• servers — Pterodactyl server allocations
• whitelist_entries — Server whitelist management

When optimizing Arbiter:

• Check for missing indexes on foreign keys
• Use timestamptz for all time columns
• Consider partial indexes for active subscriptions
• Use cursor pagination for listing endpoints

---

USEFUL QUERIES FOR ARBITER

Check Index Usage

SELECT relname, indexrelname, idx_scan, idx_tup_read
FROM pg_stat_user_indexes
ORDER BY idx_scan DESC;

Check Table Sizes

SELECT relname, pg_size_pretty(pg_total_relation_size(relid))
FROM pg_stat_user_tables
ORDER BY pg_total_relation_size(relid) DESC;

Active Connections

SELECT count(*), state
FROM pg_stat_activity
WHERE datname = 'arbiter_db'
GROUP BY state;

---

Source: skill.fish — affaan-m/everything-claude-code (Based on Supabase Agent Skills, MIT License) Added: 2026-04-09 by Chronicler #73

Fire + Frost + Foundation = Where Love Builds Legacy 💙🔥❄️