On Tue, May 8, 2012 at 7:40 PM, Tilsley, Jerry M. <jmtils...@st-claire.org>wrote:
> I have set the timeout now and will monitor this change, on the note of > using WAL I do have a question. The database is accessed by SQLite 3.6.4 > from a vendor's application, but on command-line I used 3.7.9; am I asking > from trouble? Should I go through the effort to force the vendor's > application to use the 3.7.9 version when talking to my custom DB? > SQLite 3.6.4 is unable to read a WAL database. I recommend you update the database in the vendors application. > > -----Original Message----- > From: sqlite-users-boun...@sqlite.org [mailto: > sqlite-users-boun...@sqlite.org] On Behalf Of Duquette, William H (318K) > Sent: Tuesday, May 08, 2012 5:13 PM > To: General Discussion of SQLite Database > Subject: Re: [sqlite] SQLite via TCL Question > > > > On 5/8/12 1:51 PM, "Tilsley, Jerry M." <jmtils...@st-claire.org> wrote: > > >This is probably a newbie question so please bear with me. I'm > >accessing a SQLite database through TCL and periodically I get a > "Database Locked" > >error. This is a multi-thread process that writes to the DB, do I need > >to enable WAL for this, if so, do I do this from the TCL side or the > >command-line side? > > If only one thread is writing, then using WAL should do the trick; the > other threads can read while the writer is writing. If multiple threads > are writing, that's a whole different issue, and WAL (while it might still > be a good idea) won't prevent the problem. > > You enable WAL mode using the "journal_mode" pragma; once it's set it's > persistent. So you'd want to set it when creating a new database, wherever > you do that; on an existing database, wherever you like. See > sqlite.org/wal/html. > > If you've gotten multiple writers you can set a lock timeout using the > database handle's "timeout" subcommand; it defaults to 0.0. You'll still > need to handle lock errors, though; a timeout isn't a guarantee. > > Will > > > -- > Will Duquette -- william.h.duque...@jpl.nasa.gov Athena Development Lead > -- Jet Propulsion Laboratory "It's amazing what you can do with the right > tools." > > > > > > > > >________________________________ > > > >Disclaimer**** > >This email is confidential and intended solely for the use of the > >individual to whom it is addressed. Any views or opinions presented are > >solely those of the author and do not necessarily represent those of St. > >Claire Regional Medical Center. If you are not the intended recipient, > >be advised that you have received this email in error and that any use, > >dissemination, forwarding, printing or copying of the email is strictly > >prohibited. If you received this email in error please notify the St. > >Claire Regional Helpdesk by telephone at 606-783-6565. > >_______________________________________________ > >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 > > ________________________________ > > Disclaimer**** > This email is confidential and intended solely for the use of the > individual to whom it is addressed. Any views or opinions presented are > solely those of the author and do not necessarily represent those of St. > Claire Regional Medical Center. If you are not the intended recipient, be > advised that you have received this email in error and that any use, > dissemination, forwarding, printing or copying of the email is strictly > prohibited. If you received this email in error please notify the St. > Claire Regional Helpdesk by telephone at 606-783-6565. > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > -- D. Richard Hipp d...@sqlite.org _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
