[OSM-dev] osm2pgsql tile expiry performance

[j]

> To be fair, I am not sure this is even related to tile expiration. I
> have not tried 0.96 updates without tile expiration as a baseline.

After 3 hours, the same update has reached the same state of progress.
osm2pgsql (debian backport) 0.96 maintains < 1GB of memory usage without
expiring tiles. While expiring tiles, it ballooned to >22GB before
being killed.

Seems the issue is specific to tile-expiration overhaul. 

I note that initial testing of this code used an extract of Europe:
https://github.com/openstreetmap/osm2pgsql/pull/747

I did not note it earlier, but I am working with the planet. I doubt
these issues would present themselves on a modestly sized machine
working with Europe only.

j