Some mbtiles tool operations produce db or disk/machine out of space errors

[nyurik]

The "database or disk/machine out of space" error seems to be coming from SQLite, and has not yet been reliably reproduced. It is known that there is plenty of both RAM and harddisk space (maybe some small temporary partition is being used? needs investigation).

This has been seen when using

• mbtiles validate on arm64
• mbtiles copy on x64

Reported error:

(code: 13) database or disk is full

[nyurik]

This might have been by #1156, but since we have no reliable way to reproduce, will keep this open for a bit

[nyurik]

It seems this issue is caused by SQLite using /tmp directory which on some machines uses a different mounted partition, which may be significantly smaller. Per https://www.sqlite.org/tempfiles.html , the best way to fix this might actually be to set the SQLITE_TMPDIR env var to point elsewhere, which is obviously outside of mbtiles control. I will add this to documentation though.

[nyurik]

Confirmed that I can reproduce it with the latest martin docker image. See also SQLite docs temp files - /var/tmp would be the first temp dir pick for SQLite here.

# Create a docker volume with a limited size, e.g. 1MB
docker volume create  --driver local  --opt type=tmpfs  --opt device=tmpfs  --opt o=size=1m  tmp

# Run martin container, mounting tmp volume as the SQLite's choice for a tmp dir (see link above)
# This command must run in a directory that contains some multi-megabyte mbtiles file
docker run --rm -it --mount source=tmp,target=/var/tmp -v $PWD:/data --entrypoint sh ghcr.io/maplibre/martin:latest

# Inside docker, run validation command using your data file:
mbtiles validate /data/my_data_file.mbtiles

Result:

[INFO ] Quick integrity check passed for /data/my_data_file.mbtiles
[INFO ] All values in the `tiles` table/view are valid for /data/my_data_file.mbtiles
[INFO ] All tile hashes are valid for /data/my_data_file.mbtiles
[ERROR] error returned from database: (code: 13) database or disk is full

Make sure to delete tmp volume once done with docker volume rm tmp