clickhouse-js-node-troubleshooting

Something has gone wrong between a Node.js app and its ClickHouse database — this works back from the symptom to the actual cause, and names the cause before handing you the fix.

WHEN TO USE

SCOPE

USE FOR

Diagnose a connection that drops or hangs during a long-running query.
Fix a large integer or decimal that comes back with the wrong precision.
Work out why response compression fails for a read-only user.
Fix the wrong database being selected behind a proxy with a path prefix.
Get logging output working when the client shows nothing at all.

NOT FOR

Fix browser, Web Worker, or Next.js Edge runtime problems — those run on @clickhouse/client-web.

This is a saved copy of the skill's SKILL.md instructions. It may differ from the upstream file or the version you install.

In this document (4)

ClickHouse Node.js Client Troubleshooting

Reference: https://clickhouse.com/docs/integrations/javascript

⚠️ Node.js runtime only. This skill covers the @clickhouse/client package running in a Node.js runtime exclusively — including Next.js Node runtime API routes, React Server Components, Server Actions, and standard Node.js processes. Do not apply this skill to browser client components, Web Workers, Next.js Edge runtime, Cloudflare Workers, or any usage of @clickhouse/client-web. For browser/edge environments, the correct package is @clickhouse/client-web.

How to Use This Skill

Identify the issue — match symptoms to the Issue Index below and read the corresponding reference file.
Lead with the diagnosis — explain what's likely causing the issue before giving the fix.
Note version constraints — flag if a fix requires a minimum client version and check it against what the user provided.
Ask only what's missing — if the fix is version-dependent and you don't know their version, ask; otherwise help immediately.

Issue Index

Identify the user's issue from the list below and read the corresponding reference file for detailed troubleshooting steps.

Issue	Symptoms	Reference file
Socket Hang-Up / ECONNRESET	`socket hang up`, `ECONNRESET`, intermittent connection drops, long-running queries timing out	`reference/socket-hangup.md`
Data Type Mismatches	Large integers returned as strings, decimal precision loss, Date/DateTime insertion failures, `CANNOT_PARSE_INPUT_ASSERTION_FAILED` inserting a UUID into a `UInt128` column	`reference/data-types.md`
Read-Only User Errors	Errors when using response compression with `readonly=1` users	`reference/readonly-users.md`
Proxy / Pathname URL Confusion	Wrong database selected, requests failing behind a proxy with a path prefix	`reference/proxy-pathname.md`
TLS / Certificate Errors	TLS handshake failures, certificate verification issues, mutual TLS setup	`reference/tls.md`
Compression Not Working	GZIP compression not activating for requests or responses	`reference/compression.md`
Logging Not Showing Anything	No log output, need custom logger integration	`reference/logging.md`
Query Parameters Not Interpolated	Parameterized queries not working, SQL injection concerns	`reference/query-params.md`
FORMAT Clause / `SHOW POLICIES` Errors	Syntax error from a duplicate `FORMAT`, or `SHOW [ROW] POLICIES` failing even with a format provided	`reference/query-format-clause.md`

Still Stuck?

Local tool required

1 FOR YOU

01
Use it in a project running @clickhouse/client
This skill diagnoses errors from the @clickhouse/client Node.js package, so you need that package installed in a Node.js project (and its version handy) for the fixes to apply.

This skill ships inside the ClickHouse Agent Skills plugin.

Run this outside your AI tool, using Node.js 22.20.0 or newer. Skills CLI 1.7.2 skips skill selection; prompts cancel installation without an interactive terminal. If choosing Project when asked about installation scope, open your project's folder before running this.

Install checklist

Check selected tools if a picker appears; Claude Code may be unchecked under Additional agents. ↑/↓ moves, Space toggles selections, Enter confirms.
Without a tool picker, check Installing to: for your intended tool. Stop if it names a different tool.
If asked, choose Symlink (Recommended) for shared files or Copy to all agents for separate copies; review the summary before confirming installation.
Install the find-skills skill? defaults to Yes, adding another skill for all projects. Choose No if you don't want that extra installation.

Skills CLI 1.7.2 sends install data to skills.sh by default, including the source, skill names, target tools and file details; GitHub sources are reported only when GitHub confirms the repository is public, while other remote sources can also be reported. Confirmed-public GitHub sources also trigger a security-audit request. Before installing, set the environment variable DO_NOT_TRACK=1 or DISABLE_TELEMETRY=1 to disable both.

npx skills add clickhouse/agent-skills --skill "clickhouse-js-node-troubleshooting" --full-depth

After installing for Claude Code, open it in the installation project if you chose Project; Global makes the skill available across projects on this computer. Once Claude Code loads the skill, its description helps Claude decide when to use it.

If installation created a top-level skills folder that did not exist when your Claude Code session started, run /reload-skills in that session. Run it again after later changes in that folder.

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ClickHouse Node.js Client Troubleshooting

How to Use This Skill

Issue Index

Still Stuck?

Local tool required

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MCP keyword matches