On 11/24/16, Florian Weimer <fwei...@redhat.com> wrote: > I'd like to replace the use of Berkeley DB in RPM with SQLite. > > The scenario is special in the follow way. There is no database server, > all access goes directly to the database. Unprivileged users without > write access to the RPM database are expected to run read-only queries > against the database. Privileged users (basically, root) is expected to > use locking to exclude concurrent writers. But read-only users should > not be able to stop acquisition of a write lock. > > Is there a way to do this with SQLite?
The readers can open the database using URI filenames (https://www.sqlite.org/uri.html) with query parameters "mode=ro" and "locking=0". That will prevent the readers from blocking the writer. But, if a write happens in the middle of a read, the reader might see inconsistent data and report SQLITE_CORRUPT. This is harmless in the sense that the database file is not really corrupt (the reader is merely seeing parts of the files from two different points in time) and subsequent reads should still work. If you are unlucky, a write that happens at the same time as a read might cause the reader to return incorrect results, so the reader can never be 100% sure that the answer it gets back is correct. How important is it to you that the reader always get a correct answer? -- D. Richard Hipp d...@sqlite.org _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
