| 1 | -- The runner's own number for each batch of a job's log (1 for its first), |
| 2 | -- which a batch keeps when the runner sends it again after an answer it did |
| 3 | -- not hear: a batch g1t already has is not kept twice. Null for runners that |
| 4 | -- do not number their batches; nulls never collide in a unique index. |
| 5 | ALTER TABLE logs ADD COLUMN chunk INTEGER; |
| 6 | CREATE UNIQUE INDEX logs_by_chunk ON logs (job_id, chunk); |