Binary Heap

A priority queue, demoing the p/moul/x/daily/heap library.

The workload

job	priority
send email	5
pay invoice	1
backup db	3
rotate keys	1
clear cache	9

Min-heap — lowest priority first

#	job	priority
1	pay invoice	1
2	rotate keys	1
3	backup db	3
4	send email	5
5	clear cache	9

Max-heap — highest priority first

#	job	priority
1	clear cache	9
2	send email	5
3	backup db	3
4	pay invoice	1
5	rotate keys	1

Ties

pay invoice and rotate keys share priority 1. Both heaps pop them oldest-first: the tiebreak is insertion order and does not invert with the heap kind.

Without a total order, two nodes could pop equal-priority items in different sequences and render different pages — a consensus bug, not a cosmetic one.