postgres-patterns

A reference guide for PostgreSQL, a database system, covering query speed, table design, indexes, security, and connection pooling. It is based on Supabase practices.

In plain words
What is it for?
Use it when writing SQL or migrations, designing tables and indexes, troubleshooting slow queries, configuring row-level security, or setting up connection pooling.
Why use it?
It helps avoid common database design and query mistakes that can lead to slow searches, weak access controls, or inefficient connections.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/ashfaqbs/software-dev-ai-claude-toolkit/postgres-patterns
Any agent
npx skills add Ashfaqbs/software-dev-ai-claude-toolkit --skill postgres-patterns
Clone the repo
git clone --depth 1 https://github.com/Ashfaqbs/software-dev-ai-claude-toolkit

Made for: Claude Code, Codex.

Per session 28 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,018 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 94% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00028 $0.01018
Opus 5 $0.00014 $0.00509
Sonnet 5 $0.00006 $0.00204
Haiku 4.5 $0.00003 $0.00102

Measured 2d ago against content hash f38ed542ddcc, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

postgres-patterns scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

94% identical to postgres-patterns — 6 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/postgres-patterns/SKILL.md · 147 lines

How it starts

The opening of the file, as written. The whole thing — 147 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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)

Read the full file on GitHub · 147 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 147 lines · 28 tokens per session scan A f38ed542ddcc

Subscribe to this mod's changes

postgres-patterns is a skill published in the GitHub repository Ashfaqbs/software-dev-ai-claude-toolkit (24 stars, last pushed 6mo ago), licensed MIT. It adds 28 tokens to every session and 1,018 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 94% identical to postgres-patterns, differing in 6 lines, and is treated as a copy.

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