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mopidy / mopidy-local-sqlite

DEPRECATED (Mopidy SQLite local library extension)
https://mopidy.com
Apache License 2.0
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Reduce Database Locking During Local Scan #27

Closed tkem closed 10 years ago

tkem commented 10 years ago

When starting Mopidy while a local scan is running, it will most likely fail due to a connection timeout. Rethink transactions/locking/isolation levels, e.g. commit after every insert.

tkem commented 10 years ago

This behavior is not always reproducable -- often/mostly, Mopidy will start up fine during a local scan, correctly reporting the number of local tracks already committed.

tkem commented 10 years ago

May be related to the size of the library.db-journal, i.e. the number of tracks being updated. Could be observed with library.db-journal > 1.5MB, or > 4000 tracks.

tkem commented 10 years ago

Performing each INSERT in a seperate transaction fixes this, but increases the total time for a local scan about a factor of 3. Addtionally, this will probably result in more disk writes, which may affect platforms running off SD cards, for example.

Another option would be to set local/scan_flush_threshold to a lower value, e.g. 100 (the default 1000 seems a little bit excessive, anyway). Thus, the journal file seems to stay well beneath 500KB, and no database timeouts could be observed. So this should be added as a recommendation to the README.