postgresql-development

A set of development practices for PostgreSQL, a relational database used to store structured application data. It covers database structure, SQL queries, indexes, performance, migrations, backups, and operations.

In plain words
What is it for?
Design PostgreSQL schemas, write advanced SQL, inspect slow queries with EXPLAIN ANALYZE, choose indexes, manage migrations and transactions, configure connection pooling, and handle backups or restores.
Why use it?
It helps keep data valid and queries efficient as an application grows. The guidance emphasizes enforcing rules in the database and measuring query performance before tuning it.

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/dallay/agents-skills/postgresql-development
Any agent
npx skills add dallay/agents-skills --skill postgresql-development
Clone the repo
git clone --depth 1 https://github.com/dallay/agents-skills

Made for: Claude Code, Codex.

Per session 58 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,802 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found 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 $0.00058 $0.02802
Opus 5 $0.00029 $0.01401
Sonnet 5 $0.00012 $0.00560
Haiku 4.5 $0.00006 $0.00280

Measured 2d ago against content hash 0d26a85da6b9, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

postgresql-development 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.

skills/postgresql-development/SKILL.md · 317 lines

How it starts

The opening of the file, as written. The whole thing — 317 lines — stays where its author put it; the contents beside it link to each section on GitHub.

When to Use

  • Designing PostgreSQL schemas with proper constraints, types, and indexes.
  • Writing advanced queries using CTEs, window functions, JSONB, or array operations.
  • Analyzing and optimizing slow queries with EXPLAIN ANALYZE.
  • Setting up indexing strategies (B-tree, GIN, GiST, partial, covering indexes).
  • Configuring connection pooling with PgBouncer or built-in poolers.
  • Managing migrations, transactions, isolation levels, and data integrity.
  • Tuning PostgreSQL server parameters for workload characteristics.
  • Backup, restore, and disaster recovery with pg_dump and pg_basebackup.

Critical Patterns

  • Constraints at the Database Level: Enforce NOT NULL, CHECK, UNIQUE, and foreign keys in the schema — never rely solely on application-level validation. The database is the last line of defense.
  • Index Deliberately: Every index has a write cost. Create indexes based on actual query patterns from EXPLAIN ANALYZE, not speculation. Monitor with pg_stat_user_indexes to find unused ones.
  • Use Appropriate Types: Use uuid (not VARCHAR) for identifiers, timestamptz (not timestamp) for times, text (not VARCHAR(n)) for variable strings, numeric for money, and jsonb (not json) for document data.
  • CTEs Are Not Optimization Barriers (since PG 12): PostgreSQL can inline CTEs. Use them freely for readability. Add MATERIALIZED only when you explicitly need to force a single evaluation.
  • Connection Pooling Is Mandatory: PostgreSQL forks a process per connection. Always use PgBouncer (or Supavisor, pgcat) in front of PostgreSQL in production. Target max 100-200 actual connections.
  • Transactions Should Be Short: Long-running transactions hold locks and block autovacuum. Keep transactions under a few seconds. For bulk operations, use batched commits.
  • Always EXPLAIN ANALYZE: Never guess at query performance. Use EXPLAIN (ANALYZE, BUFFERS, FORMAT TEXT) to see actual row counts, buffer hits, and execution time.

Read the full file on GitHub · 317 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 · 317 lines · 58 tokens per session scan A 0d26a85da6b9

Subscribe to this mod's changes

postgresql-development is a skill published in the GitHub repository dallay/agents-skills (2 stars, last pushed 10d ago), licensed MIT. It adds 58 tokens to every session and 2,802 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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