Overpass API developpement

[Roland Olbricht <>]

Hi all,

a performance regression for 0.7.59 has been observed on systems that
are disk bound. The root cause for this is that the exchange of mmap(..)
for read(..) triggers different caching strategies by the OS. As
mmap(..) at the same time elides the copy from kernelspace to userspace
of all raw data, it does improve the performance on all CPU bound
systems (like the public default instances).

By an A/B testing it turned out that the disk usage can be restored to
usual patterns and still the memory copy can be avoided, getting the
best for both scenarios (disk bound as well as CPU bound) with the
syscall posix_madvise. This is what 0.7.59.1 delivers. If you run an
instance that is disk bound then I suggest to install that patch soon.

Cheers,

Roland