On 27 April 2016 at 13:01, Mark Foley <mfoley at novatec-inc.com> wrote: > > Can sqlite handle contention among multiple accessors with read/write if > the > accessors are not on the same host? I.e. is locking intrinsic in sqlite > and any > accessor from any host is able to determine and set a row/table lock? >
That depends on the journal mode, and the file systems used to access the database. WAL is not suitable for access via multiple hosts as it relies on shared memory. sqlite relies on the locking primitives provided by the file system - for this to work across hosts the network file system has to plumb the locking calls through to the host system correctly. For a quick test you can open the sqlite3 shell on the same database on both the file server and remote machine - run "BEGIN IMMEDIATE;" in one and then run "BEGIN IMMEDIATE;" in the other. On the second attempt you should encounter "database is locked". That demonstrates the network file system at least propagates locks, but doesn't prove it behaves correctly in all scenarios (there may be race conditions etc). -Rowan
