What is db-connection-pooling?

A review that checks how an application manages database connections, especially with Postgres. It covers serverless functions, transaction-mode poolers such as PgBouncer, and connection limits.

Use it to inspect direct Postgres connections from serverless functions, incompatible session features, and pool sizes across application instances.

It helps find connection exhaustion and pooling mistakes that can cause outages or make requests wait unnecessarily. A pooler is a service that reuses a limited set of database connections.

db-connection-pooling — Skill for Claude Code by Hainrixz

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.

Any agent

npx skills add Hainrixz/claude-db --skill db-connection-pooling

Clone the repo

git clone --depth 1 https://github.com/Hainrixz/claude-db

Made for: Claude Code.

Or install claude-db, the plugin that ships this one along with the rest of its 36 skills, 6 agents, 1 hook.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/hainrixz/claude-db/db-connection-pooling/github.svg)](https://agentmods.dev/skills/hainrixz/claude-db/db-connection-pooling)

Your own site

<a href="https://agentmods.dev/skills/hainrixz/claude-db/db-connection-pooling"><img src="https://agentmods.dev/badge/skills/hainrixz/claude-db/db-connection-pooling/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/hainrixz/claude-db/db-connection-pooling"><img src="https://agentmods.dev/badge/skills/hainrixz/claude-db/db-connection-pooling.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,169 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00055	$0.01169
Opus 5	$0.00028	$0.00584
Sonnet 5	$0.00011	$0.00234
Haiku 4.5	$0.00006	$0.00117

Measured 9d ago against content hash 311e8c318077, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

db-connection-pooling 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 9d 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/db-connection-pooling/SKILL.md · 86 lines

How it starts

The opening of the file, as written. The whole thing — 86 lines — stays where its author put it; the contents beside it link to each section on GitHub.

db-connection-pooling (M15)

Connection exhaustion is a top cause of production outages and a pure Performance & Scale (axis performance) concern. Feeds relational Pooling w10 (and the Conexión category in every NoSQL profile). The dominant modern failure is serverless functions opening one direct connection each and saturating the backend.

What it checks

Serverless + direct Postgres — a function/edge runtime (Vercel/Lambda/Cloudflare/Netlify) connecting directly to Postgres with no pooler. Each cold start opens a connection; concurrency spikes blow past max_connections. Recommend a transaction-mode pooler or a serverless driver (Neon/@neondatabase/serverless, Supabase pooler, PlanetScale HTTP).
Transaction-mode pooler misuse — using a transaction-pooling endpoint (PgBouncer transaction mode, Supabase port 6543) while relying on session features it breaks: server-side prepared statements, SET/session GUCs, LISTEN/NOTIFY, advisory-session locks.
Pool sizing — application pool max × instance count exceeding backend max_connections, or a pool so small it serializes requests.

Sizing block

The server-connection ceiling is roughly a small multiple of vCPU, not your peak concurrency. Frame (cores*2) + effective_spindles as the server-side ceiling on usefully-busy backend connections — not a per-app-pool target.
Size the client pool to that ceiling, not to peak request concurrency. More backend connections than the server can usefully run just adds context-switch and lock contention; queue at the pool, not the database.
Reserve headroom below max_connections — leave superuser_reserved_connections (and room for other apps/replication) free so an admin can still connect when the pool saturates.
PgBouncer transaction mode multiplexes many client connections onto a few backend connections, so the client pool can far exceed the backend ceiling — but session-level features break under it (server-side prepared statements, SET/session GUCs, LISTEN/NOTIFY, session-scoped advisory locks).

Read the full file on GitHub · 86 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.

9d ago First seen · 86 lines · 55 tokens per session scan A 311e8c318077

Subscribe to this mod's changes

db-connection-pooling is a skill published in the GitHub repository Hainrixz/claude-db (19 stars, last pushed 2mo ago), licensed MIT. It adds 55 tokens to every session and 1,169 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 2026-08-30.

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