Clickhouse Common Errors

What it does

When your agent uses it

• A ClickHouse query
• Insert throws an exception
• A server-side error appears in logs
• A failed query needs root-cause analysis

Example prompts

• “clickhouse error”
• “fix clickhouse”
• “clickhouse not working”
• “/clickhouse-common-errors”

Requirements

• Compatibility (from SKILL.md): Designed for Claude Code
• Pre-approved tools (allowed-tools): Read, Grep, Bash(curl:*)

Workflow steps

4 steps, taken from the first numbered list in SKILL.md.

1. 1Capture the exception name and code. Read the error string the client
2. 2Map it to a category. Use the Error Handling code table
3. 3Apply the inline fix for the three top errors (Too Many Parts, Memory
4. 4Confirm with a system table. Re-run the relevant system.* query (part

What it can do on your machine

Read from SKILL.md and the folder at commit 80f86df. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves these tools, so the agent can use them without asking each time:

  • Read
  • Grep
  • Bash(curl:*)

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  No scripts in the folder and no shell commands in SKILL.md (its code samples are sql).

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  Links to these hosts (documentation or services it may open):

  • clickhouse.com

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

• Compatibility

  Designed for Claude Code

  From compatibility in the SKILL.md frontmatter.

Context cost

Clickhouse Common Errors loads about 1.5k tokens when it runs, and up to ~2.9k if it reads all its reference files. Until then it costs about 107 tokens; SKILL.md has 522 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~107

When it runs · the whole SKILL.md, loaded when a task matches

~1.5k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~2.9k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from jeremylongshore/tons-of-skills-marketplace at commit 80f86df, republished under its MIT licence (© jeremylongshore). 522 words, ~1,481 tokens.

name

clickhouse-common-errors

description

Diagnose and fix the top 15 ClickHouse errors — query failures, insert problems, memory limits, and merge issues. Use when a ClickHouse query or insert throws an exception, a server-side error appears in logs, or a failed query needs root-cause analysis. Trigger with "clickhouse error", "fix clickhouse", "clickhouse not working", "debug clickhouse", "clickhouse exception", "clickhouse syntax error".

allowed-tools

Read, Grep, Bash(curl:*)

compatibility

Designed for Claude Code

version

1.7.0

license

MIT

author

Jeremy Longshore <jeremy@intentsolutions.io>

tags

saas, database, analytics, clickhouse, olap

-- Check current part count per table
SELECT database, table, count() AS part_count
FROM system.parts WHERE active GROUP BY database, table ORDER BY part_count DESC;

-- Temporary relief; permanent fix is batching (10K+ rows per INSERT)
ALTER TABLE events MODIFY SETTING parts_to_throw_insert = 1000;  -- default 300

SET max_memory_usage = 20000000000;             -- 20GB for this query, OR
SET max_bytes_before_external_group_by = 10000000000;  -- spill big GROUP BY to disk

SELECT "user_id" FROM events;          -- double-quote (not `backtick`) identifiers
SELECT * FROM events LIMIT 10 OFFSET 20;  -- OFFSET keyword, not LIMIT 10, 20

© jeremylongshore, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 1 other file (references) in skills/.curated/clickhouse-common-errors of jeremylongshore/tons-of-skills-marketplace.

• SKILL.md
• references/error-reference.md

Open the folder on GitHubat commit 80f86df