## Summary
On the run-ops split, NEW-residency runs could hang. Time-based waits
(`wait.for`, `wait.until`, `delay`, waitpoint tokens),
`batchTriggerAndWait`, and attempt starts stalled and never resumed.
Each was a run-ops read or update that hit the wrong database: either
the owning store's read replica when it needed read-your-writes, or the
wrong store entirely because it routed by an id that does not encode
residency.
## Fixes
**Waitpoint resume (the main hang).** The managed resume path reads a
run's completed waitpoints by snapshot id
(`findSnapshotCompletedWaitpointIds`). Snapshot ids are cuids, which
always classify to the legacy store, so a NEW run's join rows (which
live on the new store) were never found. The resumed run saw zero
completed waitpoints and hung. It now fans out across both stores and
merges, like its sibling readers.
**Batch completion.** Batch item completion
(`updateManyBatchTaskRunItems`) routed by the item id, which is also a
cuid, so a NEW batch's items were updated on the wrong store, matched
zero rows, and the batch was treated as already complete (its parent's
`batchTriggerAndWait` then hung). It now routes by the batch id, which
does encode residency, matching the sibling `countBatchTaskRunItems`.
**Read-your-writes on the resume path.** The block-time
pending-waitpoint check (`countPendingWaitpoints`) and the attempt-start
lock check (`findRun` in `startRunAttempt`) both read the owning store's
replica with no read-your-writes guarantee, so a just-committed
waitpoint completion or dequeue lock could be missed under replica lag
and strand the run. Both now read the owning primary.
Each fix ships with a two-database store or engine test that reproduces
the hang and passes with the fix.
Daniel Sutton
f101983a70