FYI:
To solve the performance problems on lower zoom level, I modify expire.rb a little bit so that we have now no fix MIN_ZOOM value. Instead the MIN_ZOOM is changing with definable probabilities. [1] (Expiring works on zoomlevel MIN_ZOOM to MAX_ZOOM).
Low zoom-levels cost us a lot and changes are often not visible.
So edits on OSM leads to expirings on higher zoom-level with a higher probability than on low levels. Areas with high mapping activities will re-render more often than death areas.
Z16-18 will expire each time. z10 will only expire with a probability of 1.5%. We can adjust this values each time.
I hope this help us if we restart the updating of the db, where this script works.
[1] random= rand() prob=[0,0,0,0,0,0,0,0,0,0.00625,0.0125,0.025,0.05,0.1,0.2,0.4,1,1,1] #probability for each zoomlevel to expire z = 18 while z > 0 if random<prob[z] mini=z end z -= 1 end MIN_ZOOM=mini