Surf Roots, Software Thoughts » Databases http://alexlod.com A blog by Alex Loddengaard Thu, 02 Feb 2012 03:25:19 +0000 en hourly 1 http://wordpress.org/?v=3.3.1 SQLite3: Beware of Concurrency http://alexlod.com/2008/10/14/sqlite3-beware-of-concurrency/ http://alexlod.com/2008/10/14/sqlite3-beware-of-concurrency/#comments Tue, 14 Oct 2008 17:15:49 +0000 Alex Loddengaard http://www.alexloddengaard.com/?p=750 Continue reading →]]> SQLite3 is a very lightweight implementation of a SQL database.  I’ve been using it in conjunction with Python on a single-threaded tool.  This morning I started refactoring my tool to have multi-process support, but I was interrupted by the following error:

sqlite3.OperationalError: database is locked

After reading through the SQLite3 documentation, I found that SQLite3 does database-level locking when performing write operations.  This means that all hope of parallelizing SQLite3 write operations is lost, because SQLite rejects a concurrent write attempt to the same database.

And I thought MySQL‘s table-level locking was bad (unless you’re using InnoDB) …

Update: for the record, PostreSQL does row-level locking.

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