Sairam, Just in case it's useful and you've not see it, Simon Slavin pointed out this "rqlite" project for replicated sqlite in an email from 25 Feb.
Donald ================================================ Simon Slavin slavins at bigfraud.org via <https://support.google.com/mail/answer/1311182?hl=en> mailinglists.sqlite.org Feb 25 (11 days ago) to SQLite This looks interesting. <http://www.philipotoole.com/replicating-sqlite-using-raft-consensus/> <https://github.com/otoolep/rqlite> It allows you to set up multiple computers on the internet to keep copies of a database in synch. Changes in one are promulgated to them all. As a side effect it proves a TCP server for SQL commands. Haven't had time to evaluate it, but there are people here who can do that far better than I can. Simon. On Mon, Mar 7, 2016 at 7:36 AM, Simon Slavin <slavins at bigfraud.org> wrote: > > On 7 Mar 2016, at 12:24pm, Sairam Gaddam <gaddamsairam at gmail.com> wrote: > > > I want to make note of those changes and replicate in another DB. > > Okay. > > Reading changes from the WAL file is perhaps a poor way to do this. > First, not all SQLite databases have a WAL file. Second, SQLite can put > changes in the WAL file and then immediately process them and overwrite the > contents of the file. Third, because you are modifying database files > outside of sqlite you stand the chance of corrupting those files. Fourth, > you would need to have a constantly-running process to see what is going on > and this wastes a lot of CPU and power. > > The standards way to ensure database replication is to do the following. > Either > A) Always make changes via your own library routine which logs them OR > B) Rewrite sqlite3_exec() or sqlite3_prepare() to log changes as well as > do their normal job. > > To log a change, create a new SQL table called 'change_log' and add to it > all commands which start with INSERT, UPDATE or DROP. > > Then your routine simply reads that table, executes those commands on > another database file (you can use ATTACH or send the changes as a text > file to another computer) then does "DELETE FROM change_log". > > If your database files are small and you do not make changes frequently > then you could instead use the SQLite Backup API: > > <https://www.sqlite.org/backup.html> > > Simon. > _______________________________________________ > sqlite-users mailing list > sqlite-users at mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users >
