As long as you are and remain in serialized mode, you can re-use the same connection from different threads.
If you can guarantee that each thread will have it's own, personal, connection, you may achieve a performance increase by using multithread mode. In single thread mode, all the checks are turned off and it is up to you to make sure that exactly 1 thread does all the calls to SQLite. This mode is fastest. -----Ursprüngliche Nachricht----- Von: sqlite-users [mailto:sqlite-users-boun...@mailinglists.sqlite.org] Im Auftrag von Torsten Curdt Gesendet: Montag, 28. Mai 2018 10:38 An: sqlite-users@mailinglists.sqlite.org Betreff: Re: [sqlite] [EXTERNAL] Re: database locked on select Thanks for the suggestion but I feel that will just make things more complex. Right now I have one function that does it work and then decides whether to update or not. That way I would have to split that one function into two (new_data, needs_update) which is not so easy. Plus that also makes things less portable (not this really is a requirement though). WAL mode seems to solve this for me much better. At least I don't see any drawbacks yet. I am just wondering if having both statements on the same connection is a valid way of using this. cheers, Torsten On Mon, May 28, 2018 at 10:25 AM Hick Gunter <h...@scigames.at> wrote: > It is possible to bring an external resource into SQlite by writing > user-defined functions and/or virtual tables. This would allow > something > like: > > UPDATE <table> set (<rowlist>) = new_data(<arguments>) where > needs_update(<arguments>); > > With the UDF returning 1 (TRUE) if the current row (identified by the > arguments) needs an update and the row-valued function new_data() > returns the new values. > > > -----Ursprüngliche Nachricht----- > Von: sqlite-users > [mailto:sqlite-users-boun...@mailinglists.sqlite.org] > Im Auftrag von Torsten Curdt > Gesendet: Montag, 28. Mai 2018 10:04 > An: sqlite-users@mailinglists.sqlite.org > Betreff: [EXTERNAL] Re: [sqlite] database locked on select > > I have to query an external resource for each row. > Unfortunately nothing I can do in a single update query. > Would mean keeping a lot of data manually in memory. > > On Mon, May 28, 2018 at 2:33 AM Abroży Nieprzełoży < > abrozynieprzelozy314...@gmail.com> wrote: > > > BTW why not to update all rows by single update query? > > > > 2018-05-27 20:30 GMT+02:00, Torsten Curdt <tcu...@vafer.org>: > > > I am doing a select, then iterate through the resultset and on > > > each row call update on that row. > > > I am using the golang driver and ran into the issue that on the > > > update > > the > > > database is still locked from the select. > > > > > > https://github.com/mattn/go-sqlite3/issues/569 > > > > > > I have read http://www.sqlite.org/cvstrac/wiki?p=DatabaseIsLocked > > > and > > IIUC > > > these types of updates should be possible since version 3.3.7 > > > though > > > - > > and > > > I am using 3.19.3. > > > > > > Any suggestion on how to track down why the updates fail? > > > > > > cheers, > > > Torsten > > > _______________________________________________ > > > sqlite-users mailing list > > > sqlite-users@mailinglists.sqlite.org > > > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-use > > > rs > > > > > _______________________________________________ > > sqlite-users mailing list > > sqlite-users@mailinglists.sqlite.org > > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > > > _______________________________________________ > sqlite-users mailing list > sqlite-users@mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > > > ___________________________________________ > Gunter Hick | Software Engineer | Scientific Games International GmbH > | Klitschgasse 2-4, A-1130 Vienna | FN 157284 a, HG Wien, DVR: 0430013 > | (O) > +43 1 80100 - 0 > > May be privileged. May be confidential. Please delete if not the addressee. > _______________________________________________ > sqlite-users mailing list > sqlite-users@mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users ___________________________________________ Gunter Hick | Software Engineer | Scientific Games International GmbH | Klitschgasse 2-4, A-1130 Vienna | FN 157284 a, HG Wien, DVR: 0430013 | (O) +43 1 80100 - 0 May be privileged. May be confidential. Please delete if not the addressee. _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
