mirror of
https://gh-proxy.org/https://github.com/klinsmaya/multica.git
synced 2026-11-10 10:26:46 +08:00
Eveandmultica-agent
9fc1d796f1
Addresses the fourth review round on MUL-5999.
1. The trigger is gone. Migration 284 now defines
lock_task_owner_workspaces(agent_id, issue_id, runtime_id), a predicate
that every statement writing agent_task_queue ownership calls in its own
WHERE clause:
INSERT INTO agent_task_queue (...)
SELECT ... WHERE lock_task_owner_workspaces($1, $3, $2)
Nine statements now carry it: the seven task INSERTs (agent.sql x5,
autopilot.sql, chat.sql), LinkTaskToIssue, and ReassignTasksToRuntime —
the last through a MATERIALIZED CTE so a bulk UPDATE evaluates the
VOLATILE predicate once instead of per row. Clearing runtime_id is
exempt: it cannot move a task into another workspace.
Calling it from the writing statement keeps the lock in the writer's own
transaction, which a separate caller-issued statement could not do for
the autocommit enqueue paths. TestTaskOwnershipWritesCallTheFence is the
trade for dropping the trigger: it scans the query files and fails the
build if a statement writes ownership without the fence.
2. The fence no longer defers to the foreign keys. The trigger version
counted only owner references that still resolved, so a deleted owner
made itself invisible: with all three gone it returned early, and with
one of three gone the count still matched. The predicate now compares
resolved owners against the number of owner arguments supplied and
returns false on any mismatch, so a stale write is rejected on its own
terms. TestLockTaskOwnerWorkspaces_RejectsUnresolvableOwner covers each
shape, including the one-of-three case.
3. Deterministic lock order. The workspace rows are locked with
ORDER BY w.id, so mirrored cross-workspace writes cannot take the same
pair in opposite orders. Honest note on the test: 25 mirrored concurrent
pairs never deadlock either way, because the current plan happens to
return the rows in a stable order — the ORDER BY is what makes that a
guarantee rather than an accident of the plan, and the test is a
regression test for the symptom.
4. The fail-closed test now tests what its name says. The previous one only
inserted a neighbour-owned task and could not have failed. The
replacement runs the actual race: a writer calls the real
CreateAgentTask, blocks on the workspace lock, teardown deletes the
workspace and commits, and the writer must come back with pgx.ErrNoRows
— the fence's own verdict. An FK doing the work instead surfaces as
SQLSTATE 23503, which the assertion rejects explicitly.
Cost: 5,000 predicate calls in 53.7 ms, about 11 us per fenced write, for
up to three indexed lookups and a shared row lock. Status, dispatch and
completion updates do not call it.
Refs MUL-5999
Co-authored-by: multica-agent <[email protected]>