fix(knowledge): store connector sync schedules at millisecond precision

The scheduler round-trips next_member_sync_at through a JavaScript Date and
claims the run by matching the value back exactly. Date carries milliseconds
while PostgreSQL stored microseconds, so a schedule written in SQL rather than
by the application became unmatchable the moment it landed on a fractional
millisecond: the connector stayed permanently due, every claim was refused, and
its members never synced.

Narrow both connector schedule columns to timestamp(3) so the two ends compare
the same value. The rewrite also rounds the stored values, so an already-wedged
row recovers on the next scheduler tick.

Also stop the claim diagnosis from asserting a queued run it cannot see — it now
reads the lock token and says so plainly when no condition explains the refusal,
which is what let this hide as ordinary contention.

Author: waleedlatif1

.github/workflows/test-build.yml

@@ -94,11 +94,14 @@ jobs:
         working-directory: packages/db
         run: bun run db:migrate
 
-      - name: Verify retired-column contract migration in PostgreSQL
+      - name: Verify schema contract migrations in PostgreSQL
         working-directory: packages/db
         env:
-          RETIRED_COLUMNS_TEST_DATABASE_URL: postgresql://postgres:postgres@127.0.0.1:5432/sim_auth_scim
-        run: bunx vitest run scripts/retired-columns.postgres.test.ts
+          MIGRATION_CONTRACT_TEST_DATABASE_URL: postgresql://postgres:postgres@127.0.0.1:5432/sim_auth_scim
+        run: >-
+          bunx vitest run
+          scripts/retired-columns.postgres.test.ts
+          scripts/connector-sync-schedule-precision.postgres.test.ts
 
       - name: Verify OAuth lifecycle and SCIM membership guards in PostgreSQL
         working-directory: apps/sim

apps/sim/lib/knowledge/connectors/member-queue.ts

@@ -161,6 +161,7 @@ async function describeUnacceptedMemberSync(
       memberSyncStatus: knowledgeConnector.memberSyncStatus,
       nextMemberSyncAt: knowledgeConnector.nextMemberSyncAt,
       syncLockToken: knowledgeConnector.syncLockToken,
+      memberSyncLockToken: knowledgeConnector.memberSyncLockToken,
       archivedAt: knowledgeConnector.archivedAt,
       deletedAt: knowledgeConnector.deletedAt,
     })
@@ -181,7 +182,14 @@ async function describeUnacceptedMemberSync(
   ) {
     return 'The member sync schedule changed after this run was scheduled'
   }
-  return 'A member sync is already queued or running for this connector'
+  if (row.memberSyncLockToken) {
+    return 'A member sync is already queued or running for this connector'
+  }
+  /**
+   * No checked condition explains the refusal. Naming a cause here instead once hid a connector
+   * that was refused on every attempt for days, because the reason read as ordinary contention.
+   */
+  return 'The connector refused the claim while no lock or status explains it'
 }
 
 /**

packages/db/migrations/0363_connector_sync_schedule_precision.sql

@@ -0,0 +1,16 @@
+-- The scheduler round-trips these schedules through a JavaScript `Date` and claims a run by
+-- matching the value back exactly. `Date` carries milliseconds while PostgreSQL stores
+-- microseconds, so a schedule written in SQL rather than by the application became unmatchable the
+-- moment it landed on a fractional millisecond: the connector stayed permanently due and every
+-- claim was refused. Narrowing to the precision the round trip can carry makes both ends compare
+-- the same value, and rounds the stored values so an already-wedged row recovers. Both columns are
+-- narrowed in one statement so the rewrite is a single pass. `knowledge_connector_member`'s
+-- `next_attempt_at` is written by the same backfill but is only ever range-compared, never claimed
+-- by equality, so it is left alone.
+--
+-- migration-safe: every deployed reader and writer of these columns goes through a JavaScript
+-- `Date`, which already truncates to milliseconds, so the discarded precision is unobservable to
+-- the running version and this needs no earlier deploy.
+ALTER TABLE "knowledge_connector"
+  ALTER COLUMN "next_member_sync_at" SET DATA TYPE timestamp (3),
+  ALTER COLUMN "next_sync_at" SET DATA TYPE timestamp (3);