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.
