FIELD NOTE / TIKTOK
The backfill passed review. Restart it.
The short film, the complete written thought, and the evidence behind it.
The TikTok edition will be linked here after its public post is verified.
The backfill passed review. Restart it.
Video caption
The backfill passed review. Restart it. Rows were written; the checkpoint was not committed. Store state transitions and negative controls outside the loop. #EricFieldNotes
Full written post / accessible read
Here is a simulated design review. Two capable models inspect a backfill plan and both say it is ready. Their agreement feels stronger than one answer. But the prompt never supplied the old failure trace, so both miss the same replay seam.
The job writes a batch, the acknowledgment is lost, and the scheduler restarts from the prior checkpoint. If the write is not idempotent for that operation, the replay can apply the effect twice. This is a known engineering pattern, not a mysterious agent-only failure.
Feed both reviewers the exact partial-write trace. Require each to predict the final row count and operation keys after a replay. Then interrupt a disposable backfill at that seam and compare the actual database state. A plausible explanation is not the oracle.
Record the chosen replay contract, the fault fixture and the accepted final state in the team's harness. Future agent sessions can use the models to propose repairs, but the protected replay must turn red when someone removes the operation key. Do this because the engineering knowledge must survive the conversation.
#EricFieldNotes
Evidence and boundary
On-screen label: SIMULATED BACKFILL. Illustrative cases are not measured incidents. Research papers and vendor documents support the stated mechanism only within their studied or documented scope.