Looking again at the mediascanner logs every time the following errors/warnings appear the service restarts itself directly after, this is probably what is causing the database to be left locked. Therefore I am adding mediascanner2 as also affects to this bug.
(mediascanner-service-2.0:4547): GStreamer-CRITICAL **: gst_date_time_to_iso8601_string: assertion 'datetime != NULL' failed
terminate called after throwing an instance of 'std::logic_error'
what(): basic_string::_S_construct null not valid
Mediascanner service starting at 2015-03-25 12:43:07.
To answer, "What can I do to prevent that?", it looks like alot of your audio files have none/invalid metadata for the year field so you could manually set these and then try importing again. However for testing purposes for this bug it would be useful to keep a copy of the original files that were causing the error (maybe you could pm one of them to me?) so we know that is the issue has been fixed.
Looking again at the mediascanner logs every time the following errors/warnings appear the service restarts itself directly after, this is probably what is causing the database to be left locked. Therefore I am adding mediascanner2 as also affects to this bug.
(mediascanner- service- 2.0:4547) : GStreamer-CRITICAL **: gst_date_time_new: assertion 'year > 0 && year <= 9999' failed
(mediascanner- service- 2.0:4547) : GStreamer-CRITICAL **: gst_mini_ object_ unref: assertion 'mini_object != NULL' failed
(mediascanner- service- 2.0:4547) : GStreamer-CRITICAL **: gst_date_ time_to_ iso8601_ string: assertion 'datetime != NULL' failed :_S_construct null not valid
terminate called after throwing an instance of 'std::logic_error'
what(): basic_string:
Mediascanner service starting at 2015-03-25 12:43:07.
To answer, "What can I do to prevent that?", it looks like alot of your audio files have none/invalid metadata for the year field so you could manually set these and then try importing again. However for testing purposes for this bug it would be useful to keep a copy of the original files that were causing the error (maybe you could pm one of them to me?) so we know that is the issue has been fixed.