[sqlite] WAL mode and backup API
Hello, if a running sqlite database is in WAL mode and a backup is performed on that db using the sqlite3_backup API, does that process is considered like a reader and can proceed concurrently with other readers and with the other writer? Thanks a lot for your answer. -- Marco Bambini http://www.sqlabs.com ___ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
Re: [sqlite] WAL mode and backup API
On 11/30/2010 05:03 PM, Marco Bambini wrote: Hello, if a running sqlite database is in WAL mode and a backup is performed on that db using the sqlite3_backup API, does that process is considered like a reader and can proceed concurrently with other readers and with the other writer? Yes. The connection to the backup source acts like any other reader. ___ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
Re: [sqlite] WAL mode and backup API
On 30.11.2010 11:32, Dan Kennedy wrote: On 11/30/2010 05:03 PM, Marco Bambini wrote: Hello, if a running sqlite database is in WAL mode and a backup is performed on that db using the sqlite3_backup API, does that process is considered like a reader and can proceed concurrently with other readers and with the other writer? Yes. The connection to the backup source acts like any other reader. BTW: Is there any chance that in the future the wal mode will avoid that the backup API will restart on DB changes during the backup loop ? Currently, even in wal mode, it does restart when changes are detected while the backup is ongoing. Marcus ___ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users ___ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
Re: [sqlite] WAL mode and backup API
BTW: Is there any chance that in the future the wal mode will avoid that the backup API will restart on DB changes during the backup loop ? Currently, even in wal mode, it does restart when changes are detected while the backup is ongoing. What happens if you open a read transaction on the source database before starting the backup? i.e. sqlite3_exec(pSource, BEGIN; SELECT * FROM sqlite_master, 0, 0, 0); ... do backup ... sqlite3_exec(pSource, COMMIT, 0, 0, 0); Does that help things any? ___ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
Re: [sqlite] WAL mode and backup API
On 30.11.2010 11:50, Dan Kennedy wrote: BTW: Is there any chance that in the future the wal mode will avoid that the backup API will restart on DB changes during the backup loop ? Currently, even in wal mode, it does restart when changes are detected while the backup is ongoing. What happens if you open a read transaction on the source database before starting the backup? i.e. sqlite3_exec(pSource, BEGIN; SELECT * FROM sqlite_master, 0, 0, 0); ... do backup ... sqlite3_exec(pSource, COMMIT, 0, 0, 0); Does that help things any? wow... what a trick! Using your hint I'm not able to reproduce any restarts! I can imagine what your hint does in wal mode, but without your input I would never came to that idea... :-) Thanks Dan! This makes the wal mode and backup API even more sexy. Marcus ___ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users ___ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
