Author: mmd
[Added to the original trac issue at 5.57pm, Tuesday, 5th May 2015]

Adding a few comments from a data consumer point of view:

According to the [http://wiki.openstreetmap.org/wiki/Overpass_API/status Overpass API status page], the data replication was hit by this bug at least twice this year. Generating the same diff file a second time with different contents will usually go unnoticed, causing later database inconsistency issues and generally loss of data (changesets only contained in the second diff write are lost).

As of today, this can only be resolved by time consuming manual repair activities or even restoring a backup and reapplying minutely diffs, during which Overpass API will serve outdated information.

It would be really helpful to have this issue analyzed in more detail and possibly even fixed. Dealing with empty diff files is not a concern. In the current case, the diff file was initially written with a size of 48375 bytes and again after the crash with a size of 2.2M.

Please also refer to this Github ticket for more details: drolbr/Overpass-API#210

Author: Jocelyn
[Added to the original trac issue at 6.25pm, Sunday, 3rd July 2016]

Wouldn't a better fix be to write temporary files before moving them to the final location ? Move operation is supposed to be an atomic operation, and if the .osm.gz is moved before the state.txt file, then no issue should be seen anymore.