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Documentation Search

The documentation search page is a small, self-contained Web UI for instant search over the embedded reference documentation. It is served from any ClickHouse HTTP port at the /docs path.

Navigate to /docs on any ClickHouse HTTP port (for example, http://localhost:8123/docs) to open it.

What it does​

The page queries the system.documentation table over HTTP as you type, and renders the selected entity's Markdown. Because it reads system.documentation, it covers every entity that table exposes — functions, aggregate functions, table functions, table engines, database engines, data types, settings, formats, compression codecs, profile events, metrics, the system tables themselves, and more — and always matches the documentation embedded in the running server.

Type in the search box and the matches appear in a type-color-coded list; selecting a match renders its documentation. Rendering includes:

  • a pencil link next to the entity's title that opens its source file on GitHub, taken from the source column of system.documentation;
  • ClickHouse SQL syntax highlighting of code blocks, using the same embedded lexer (Lexer.wasm) as the /play UI;
  • TeX math via KaTeX (for example, the formula on the corr page);
  • :::note/:::tip/… admonitions, heading anchors with shareable links, and a hover "Copy" button on code blocks;
  • relative links resolved to another documented entity in-app when it exists, otherwise to https://clickhouse.com/docs; "Related" and "Alias of" references become in-app links.

The current search term, open entity, and section are mirrored into the URL fragment, so a particular page or section can be linked to directly and is restored by browser back/forward navigation. A light/dark theme switcher (with autodetection) matches /play.

Connecting​

The header has URL, user, and password inputs, exactly like /play. When the page is served by ClickHouse, the URL defaults to the current origin; when the page is opened as a local file, it defaults to http://localhost:8123/, so the page can also be opened locally against a remote server. The cross-link name cache is rebuilt automatically when the connection changes.

Assets​

All assets — including the Markdown renderer (Marked), the math renderer (KaTeX, with its fonts), and the SQL lexer — are served from the ClickHouse binary itself when the page is served over HTTP. No third-party CDNs are loaded in the ClickHouse HTTP origin, so the page is self-contained, works offline, and does not execute third-party network code alongside the credentials it handles.

Security considerations​

The page issues queries to the ClickHouse HTTP endpoint with the credentials entered in the header, so the same caveats that apply to the HTTP protocol apply here:

  • Always serve /docs over HTTPS in untrusted environments to protect credentials.
  • Restrict access at the network level (firewall, reverse proxy, or the listen_host configuration) the same way you restrict access to the HTTP protocol.

system.documentation contains only the static reference documentation embedded in the server, so the page does not expose any data from your tables.