-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 08/04/2010 11:39 AM, Chris Hare wrote: > I have 3.6.12 in use. So how do I get around this error message> It > prevents part of my code from executing
Easy - do no create SQLite objects (connections, cursors) in one thread and use them in another(1). There isn't much harm in creating new connections and cursors as you need them, rather than ruthlessly trying to keep reusing one. Until SQLite 3.5.9 you had to use SQLite objects in the same thread that created them - ie this was a SQLite restriction(2). SQLite 3.5.9 allowed concurrent thread usage(3) although some tweaks are needed for correct concurrent error handling (needs SQLite 3.6.5) and care when using the SQLite API. Since pysqlite supports older versions of SQLite (probably back to 3.6.0!) it has the same restrictions and has not been updated to lift them as that would require a more recent minimum SQLite version in addition to code changes. There is a dedicated Python SQLite group where the authors of both Python SQLite bindings hang out (disclosure: I am one of them): http://groups.google.com/group/python-sqlite My APSW bindings are completely threadsafe taking great care to get all the threading issues correct (for example error messages require special handling and you need to be careful with the Python GIL and SQLite database mutex interactions). (1) Also be careful to close objects in the same thread. If you leave them to close themselves when the destructor runs then it could run in a different thread. (2) You could reuse the objects in multiple threads providing you took great care to not use them concurrently - ie you needed to ensure that you wrapped everything up in mutexes. pysqlite does have some flag you can set to tell it that you are doing this, are absolutely sure your code is correct, and that it shouldn't check. It is very rare for code to be absolutely correct, especially as it is updated over time and the consequences of being wrong are database corruption and being hard to reproduce. (3) Strictly speaking there isn't much actual concurrency - each database connection has a mutex and almost all operations take that mutex so operations are serialized. But it does mean you don't need to do anything in your code to ensure thread safety. Roger -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAkxZ/VcACgkQmOOfHg372QTx6wCfSdzNTgNOrvC9y1Al+8Now17j 7d0An3qjIlA9jJ9x7vbBpeuUu1ioQltr =7Ged -----END PGP SIGNATURE----- _______________________________________________ sqlite-users mailing list [email protected] http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
