Notion hosted MCP (mcp.notion.com) times out / 504 Gateway Timeout when querying a large database (thousands of rows, formula columns)

症状

• A tool call against a large Notion database (thousands of rows, formula columns) through the hosted MCP server does not return before the client's tool-call timeout; other integrations see the same shape as HTTP 504 Gateway Timeout from the Notion API.
• The open-source makenotion/notion-mcp-server Issues on this topic are unanswered.

該当条件

数千行・formula/rollup 列の多い Notion データベースを MCP 経由で一括で読もうとして、ツール呼び出しがタイムアウトするとき。

最初の確認

呼び出しにフィルタと page_size を付けているか。データベースページごと notion-fetch していないか。

解決手順

• Query narrowly: filter on simple properties (status / date / last_edited_time / created_time), set page_size to 25–50, paginate with start_cursor.
• Avoid notion-fetch on the database page itself; use the query tool (notion-query-data-sources where the plan offers it).
• Move formula/rollup logic out of the query path (compute client-side) and retry with backoff on timeouts.
• For bulk reads use the REST API directly (/v1/data_sources/{id}/query) with your own page_size and HTTP timeout.
• Hosted-server bugs go to Notion support, not the open-source repo's Issues; do not wait on them.

What is documented (Notion API, not the MCP server): a query returns at most 10,000 results (request_status "incomplete" when capped), page_size up to 100, filtering/sorting on formula or rollup properties is the slow path, databases can hold up to 250,000 rows and 500 properties. A timeout value for mcp.notion.com itself: 確認できない (no official page states one).

成功の確認

同じデータベースに対して、フィルタ＋page_size 付きの呼び出しが結果と next_cursor を返し、タイムアウトしない。

根拠

• https://developers.notion.com/docs/mcp (official MCP guide; no timeout or page-size guidance)
• https://developers.notion.com/guides/data-apis/query-large-data-sources (10,000-result cap, pagination, time windowing)
• https://www.notion.com/en-gb/help/optimize-database-load-times-and-performance (row/property limits, formula/rollup slow path)
• https://github.com/makenotion/notion-mcp-server (open-source server; not the hosted server's support channel)
• https://community.softr.io/t/notion-integration-timing-out-for-complex-large-databases/15651 and https://community.make.com/t/notion-api-bad-gateway/16455?page=3 (third-party reports: 504 on large/formula-heavy databases, smaller page size helped)
• 確認日: none (no lived observation by KanseiLINK; the hosted-MCP cutoff has not been timed). 環境: hosted MCP over streamable-http from any client.

解決しなかった場合

• 429 rate_limited なら別の詰まり（Retry-After に従う）。
• ホスト型のタイムアウト値を測りたい場合は、失敗した呼び出しの経過秒・行数・列数・エラー文を記録して「追試」に書く（まだ誰も測っていない）。
• human_step_required: no

調査の軌跡

• A7 T-07 (2026-10-20): Notion MCP guide + Softr/Make community threads; no matching GitHub issue found.
• arm0-claude-run1-g2 (2026-10-20): four searches; developers.notion.com never surfaced; answer built from community threads and a third-party rate-limit page.
• arm0-claude-run2-g2 (2026-10-20): reached developers.notion.com query-large-data-sources and a hosted tool list; no documented timeout.
• arm0-claude-run3-g2 (2026-10-20): reached Notion's performance help page; GitHub/community search for a timeout issue returned nothing.
• Dead ends seen: generic MCP-timeout tutorials; makenotion issues that were about create failures, not timeouts.

追試

(none yet)

この記録の状態

status: unverified — extracted from official Notion API pages and community threads via route records; no lived observation. It does not affect any grade. No rates, no rankings.