altinity-expert-clickhouse-replication

altinity-expert-clickhouse-replication is a skill for Claude Code, Codex from Altinity/altinity-skills. It costs 63 tokens per session (1,344 once invoked), scanned A, original, Apache-2.0.

A troubleshooting guide for ClickHouse replication, where database copies keep the same data across servers. It covers replica delay, Keeper connections, queued work, and read-only replicas.

In plain words
What is it for?
Use it to run diagnostic SQL queries, analyse replication health and queue problems, investigate Keeper connectivity, and continue to mutation troubleshooting when needed.
Why use it?
It provides targeted checks for common replication failures instead of requiring developers to inspect the database system without a starting point.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to run diagnostic SQL queries, analyse replication health and queue problems, investigate Keeper connectivity, and continue to mutation troubleshooting when needed.

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Install with agentmods
npx agentmods add skills/altinity/altinity-skills/altinity-expert-clickhouse-replication
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 Altinity/altinity-skills --skill altinity-expert-clickhouse-replication
Clone the repo
git clone --depth 1 https://github.com/Altinity/altinity-skills

Made for: Claude Code, Codex.

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.

agentmods badge for altinity-expert-clickhouse-replication

README.md
[![agentmods](https://agentmods.dev/badge/skills/altinity/altinity-skills/altinity-expert-clickhouse-replication/github.svg)](https://agentmods.dev/skills/altinity/altinity-skills/altinity-expert-clickhouse-replication)
Your own site
<a href="https://agentmods.dev/skills/altinity/altinity-skills/altinity-expert-clickhouse-replication"><img src="https://agentmods.dev/badge/skills/altinity/altinity-skills/altinity-expert-clickhouse-replication/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.

agentmods 80×15 button for altinity-expert-clickhouse-replication

Your own site · 80×15
<a href="https://agentmods.dev/skills/altinity/altinity-skills/altinity-expert-clickhouse-replication"><img src="https://agentmods.dev/badge/skills/altinity/altinity-skills/altinity-expert-clickhouse-replication.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 63 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,344 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00063 $0.01344
Opus 5.5 $0.00025 $0.00538
Sonnet 5.5 $0.00013 $0.00269
Haiku 4.5 $0.00006 $0.00134

Measured 1mo ago against content hash 68595f997be1, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

altinity-expert-clickhouse-replication 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 1mo 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.

altinity-expert-clickhouse/skills/altinity-expert-clickhouse-replication/SKILL.md · 56 lines

How it starts

The opening of the file, as written. The whole thing — 56 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Replication and Keeper health

Answers "are the replicas connected, in sync, and draining their queues?" from system.zookeeper_connection, system.replicas, system.replication_queue, system.replicated_fetches, system.events and system.text_log. Run altinity-expert-clickhouse-connection first if the connection mode, cluster and time window are not yet established.

Query packs

  • triage.sql — 2 checks: Keeper/ZooKeeper session status per host (replication-triage-01, @requires keeper), and the graded replication overview from system.replicas (replication-triage-02). Start here.
  • queue.sql — 2 checks: graded queue size per table and host (replication-queue-01), and the individual queue tasks carrying an exception or a postpone reason (replication-queue-02).
  • fetches.sql — 2 checks: fetches in flight with elapsed time and progress (replication-fetches-01), and recent DownloadPart activity (replication-fetches-02, needs system.part_log).
  • keeper.sql — 2 checks: average Keeper round-trip latency per host derived from ZooKeeperWaitMicroseconds over ZooKeeperTransactions (replication-keeper-01), and Keeper errors and warnings from the last 24 hours (replication-keeper-02, needs system.text_log).

How to run the query packs

  1. Read each pack file from this skill's directory (the skill loader prints the directory path).
  2. Run statements one at a time, never a whole file. Statements end with ; and start with a -- @check <id> <title> header; keep the id with its result.
  3. Honor -- @requires: skip the statement when the named table is missing, when keeper is required and the server has no Keeper/ZooKeeper, or when the version condition is not met. List skipped ids with the reason.
  4. Keep {cluster} as written when a cluster macro exists; otherwise apply the connection skill's rewrite rule. Any other {placeholder} is a template variable: substitute a real value first or skip the statement.
  5. On an error, record the check id and the first line of the error, then continue. Only for UNKNOWN_IDENTIFIER, run DESCRIBE TABLE system.<table> and drop the missing column.
  6. A severity column is the verdict for that row. Copy it; do not re-grade.

Read the full file on GitHub · 56 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 1mo ago Changed · +40 lines · +26 tokens per session 68595f997be1
  2. 1mo ago First seen · 16 lines · 37 tokens per session scan A d8fecdacef64

Subscribe to this mod's changes

altinity-expert-clickhouse-replication is a skill published in the GitHub repository Altinity/altinity-skills (17 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 63 tokens to every session and 1,344 once invoked, about $0.0003 per session on Opus 5.5. 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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