fix(mcp): cross-process catalog write safety via optimistic concurrency#38
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StefanSteiner merged 5 commits intoMay 26, 2026
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Replace DELETE+INSERT-in-transaction upsert with UPDATE-then-conditional-INSERT. Each statement is individually atomic at the hyperd level, preventing duplicate _table_catalog rows when multiple MCP servers share one hyperd via the daemon.
Update both the LLM-facing readme (get_readme tool) and the user-facing README.md to position the persistent database as structured, queryable memory for AI — differentiating from flat-text memory systems by emphasizing JOIN/filter/aggregate capabilities across sessions.
The macOS CI runner under load can exceed 60s for hyperd startup when 34 other tests run in the same suite. 90s gives HyperProcess::new's internal 30s callback timeout ample room to surface real errors before the outer assertion fires.
…d_by) Capture which MCP client created and last modified each table catalog entry. The `initialize` handshake provides `client_info.name` and `version` which are stored as a combined label (e.g. "Claude Code 1.0.32"). - `created_by` is set once on INSERT, never overwritten - `last_modified_by` updates on every explicit ingest (last writer wins) - Reconciliation and watchers pass None to avoid clobbering provenance - Schema migration via ALTER TABLE ADD COLUMN for pre-existing catalogs
…timeout The internal `wait_for_callback` in HyperProcess::new has a 60s timeout. On slow macOS CI runners, spawn latency can push the total blocking time past the previous 90s outer limit, causing the test to panic with a generic message instead of surfacing the real error from the daemon thread. 150s ensures the daemon thread always has time to finish and report the actual failure cause.
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Title
fix(mcp): cross-process catalog safety, provenance tracking, and queryable-memory framing
Body
Summary
_table_catalogupsert with an optimistic UPDATE-then-conditional-INSERT pattern that is safe across multiple MCP server processes sharing the samehyperdvia the daemon.created_by/last_modified_by) to_table_catalogso users can see which MCP client created or last modified a table.TestDaemonstartup.Motivation
Optimistic concurrency: PR #26 introduced the single-instance daemon so multiple MCP clients share one
hyperd. The old DELETE+INSERT upsert could interleave across processes, producing duplicate catalog rows. The new pattern eliminates this race without adding infrastructure.Provenance: When multiple AI clients share a persistent database, users need to answer "who created this table?" or "who last updated it?" The
initializeMCP handshake providesclient_info.name+versionwhich we now capture and store.Queryable memory: Unlike flat-text memory, persistent data is queryable with SQL. LLMs can JOIN, filter, aggregate, and reason over stored context. The README changes make this capability front-and-center so LLMs naturally use it.
What changed
hyperdb-mcp/src/table_catalog.rscreated_by,last_modified_by). Schema migration via ALTER TABLE ADD COLUMN.use std::fmt::Write.hyperdb-mcp/src/server.rsinitializeoverride capturesclient_infointoclient_namefield.after_ingest_catalog_updatepasses client name through. Removed stale#[expect(clippy::unused_self)].hyperdb-mcp/src/watcher.rsNonefor client_name (watchers have no client context).hyperdb-mcp/src/readme.rshyperdb-mcp/README.mdhyperdb-mcp/CHANGELOG.mdhyperdb-mcp/tests/daemon_tests.rshyperdb-mcp/tests/per_tool_database_tests.rsupsert_stub_incall sites for new 8th argument.Test plan
cargo fmt --check && cargo clippy --workspace --tests -- -D warnings— cleancargo test -p hyperdb-mcp— all green (195 tests)cargo test -p hyperdb-mcp --test per_tool_database_tests— 30 passcargo test -p hyperdb-mcp --test end_to_end_mcp_tests— 10 passdescribeoutput via live MCP sessionINSERT ... WHERE NOT EXISTSreturnsaffected_rows: 0on duplicate (no error)