Deprecate .osrm file

[mjjbell]

The .osrm file contains a node-based graph representation of the OSM data, prior to compression and edge-expansion.

It's generated by osrm-extract and only read by osrm-extract. I believe it's a hangover from when the data was too large for RAM, so was first serialised to disk. However the file contents are immediately read back into memory anyway.

Assuming the file had value beyond the extraction phase, there are inconsistencies in which metadata components are serialised.
Traffic signals and barriers are serialised to disk as part of the graph, but other metadata, such as turn lanes, restrictions and manoeuvrer overrides are not. They are only kept in memory long enough for subsequent extraction steps.

Therefore, I propose that we scrap the disk serialise/deserialise step and stop generating this file.

.osrm is one of, if not the largest file generated during processing. Given we generate many other specific files for use in later processing stages, we can stop persisting the .osrm file entirely to save storage space, and if needed serialise its contents to more targeted files.

[mjjbell]

The toolchain file overview refers to .osrm as a temporary file. However, there is a dependency on the file in osrm-components.

I'm not sure of the maintenance status of that tool, I've never used it myself. In any case, we could make serialising an optional setting on osrm-extract for debug purposes such as this.

[SiarheiFedartsou]

Is it about the same? #2055

[SiarheiFedartsou]

@mjjbell don’t you mind if I’ll try to fix that?

[mjjbell]

Yes it sounds similar.

I would suggest holding off until #6153 is applied, as it has related changes.
What is the proposed fix? To make serialising to disk optional?

[SiarheiFedartsou]

What is the proposed fix? To make serialising to disk optional?

I think so.

[SiarheiFedartsou]

Started experimenting in #6354

[dooley]

So how do i get the components.geojson now (5.27.1)?

• [ok] osrm-extract -p ~/routing/trunk/profile/standard/car.lua germany.osm.pbf
• [ok] osrm-contract germany
• [fail] osrm-components germany components.geojson

osrm-components germany small.geojson
terminate called after throwing an instance of 'osrm::util::RuntimeError'
what(): Problem opening file: germany : (possible cause: "No such file or directory") (at include/storage/tar.hpp:38)
Aborted (core dumped)

Edit: found --dump-nbg-graph. But still then the osrm-components called without parameter wrote you call map.osrm, where it should read map.osrm.nbg. Again a small on, beside the hundreds of boost messages (deprecated, ...) when compling. Anyway, this problem is solved.