> ## Documentation Index
> Fetch the complete documentation index at: https://www.towbar.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# ClickHouse selection

> Optionally declare CLICKHOUSE_DB before initial deployment.

export const UseCaseNavigation = () => {
  useLayoutEffect(() => {
    const storageKey = "towbar-use-case-open-groups";
    const groupSelector = "#sidebar li[data-title] > button[aria-expanded]";
    let restoring = false;
    let frame = 0;
    function storedGroups() {
      try {
        return new Set(JSON.parse(sessionStorage.getItem(storageKey) || "[]"));
      } catch {
        return new Set();
      }
    }
    function save(groups) {
      try {
        sessionStorage.setItem(storageKey, JSON.stringify([...groups]));
      } catch {}
    }
    function groupName(button) {
      return button.parentElement?.dataset.title;
    }
    function rememberOpenGroups() {
      const groups = new Set();
      for (const button of document.querySelectorAll(groupSelector)) {
        if (button.getAttribute("aria-expanded") === "true") {
          const name = groupName(button);
          if (name) groups.add(name);
        }
      }
      save(groups);
    }
    function restoreOpenGroups() {
      frame = 0;
      const groups = storedGroups();
      if (!groups.size) return;
      restoring = true;
      for (const button of document.querySelectorAll(groupSelector)) {
        if (groups.has(groupName(button)) && button.getAttribute("aria-expanded") === "false") {
          button.click();
        }
      }
      restoring = false;
    }
    function scheduleRestore() {
      if (!frame) frame = requestAnimationFrame(restoreOpenGroups);
    }
    function onClick(event) {
      if (restoring || !(event.target instanceof Element)) return;
      const button = event.target.closest(groupSelector);
      if (button) {
        const name = groupName(button);
        if (!name) return;
        const groups = storedGroups();
        if (button.getAttribute("aria-expanded") === "true") groups.delete(name); else groups.add(name);
        save(groups);
        return;
      }
      if (event.target.closest('a[href^="/docs/use-cases/"]')) {
        rememberOpenGroups();
      }
    }
    const observer = new MutationObserver(scheduleRestore);
    document.addEventListener("click", onClick, true);
    observer.observe(document.getElementById("sidebar") || document.body, {
      childList: true,
      subtree: true
    });
    scheduleRestore();
    return () => {
      document.removeEventListener("click", onClick, true);
      observer.disconnect();
      cancelAnimationFrame(frame);
    };
  }, []);
  return null;
};

<UseCaseNavigation />

<img className="towbar-doc-brand-logo" src="https://mintcdn.com/avgeek/1QStfcSBIWWsf0OD/assets/database-logos/clickhouse.webp?fit=max&auto=format&n=1QStfcSBIWWsf0OD&q=85&s=36934d85e2293c6ab0955b0e71a3223c" alt="ClickHouse selection logo" aria-hidden="true" width="575" height="512" data-path="assets/database-logos/clickhouse.webp" />

## Towbar manifest

```yaml title=".towbar/datastores/clickhouse-database-selection.datastore.yml" theme={"system"}
id: clickhouse-database-selection
name: ClickHouse selection
type: clickhouse
container:
  network: application
  networkAlias: clickhouse-database-selection
  resources:
    cpus: 1
    memory: 1g
secrets:
  runtime:
    - CLICKHOUSE_USER
    - CLICKHOUSE_PASSWORD
    - CLICKHOUSE_DB
environments:
  production:
    server: 192.0.2.10
```

## Configure

1. Register and prepare the example server or servers, connect the repository, and map `production` to the branch containing these files.
2. Save each Datastore credential value under **Datastore → Settings → Secrets**, deploy it first, and verify engine readiness before starting a dependent Service.
3. Sync the repository, inspect the resolved configuration, deploy manually, and perform the verification below before enabling automation.

## Verify

The intended database exists and the client is pointed at it.

For field constraints, see [Datastore manifest](/docs/datastores/manifest).