A job sent back by the heavy lane now leaves word that the lane is
wanted. The holder, and only the holder, sees it through laneWanted();
the Google Health backfill asks it where its slice budget already
stops resumable walks, after the first page, ends the slice there and
queues the rest past the deferred job's return. Holders that cannot
stop part-way run to their end as before.
The way back to the queue now returns when the oldest deferred job was
first queued; a job that has stood in line for two hours is reported
once per holder as job.heavy_lane.waiting_long at warn, so a lane held
for hours reaches the alerts.
pg-boss counts a job's expiry from the fetch and ends the handler at it, so
a job that waited for the heavy lane spent its expiry in line: a long import
let the weekly backup expire through every retry, and an upload that waited
past its own expiry was failed, stopped counting as in use and lost its
staged file to the sweep. A job that finds the lane taken now returns to
created with start_after a minute ahead, at the same attempt, in one
statement, and runs when the lane is free.
The full-history integration drain joins the lane, and the guard checks that
every heavy queue's policy lets a job go back to created.
Marc-André Bombeck