Hi D. Richard Hipp. Sorry for the late reply. I had some email settings wrong somewhere, and I didn't realize I had a reply until I remembered this and checked the archives months later. You had written:
>> >> Is there something we need to do proactively to ensure that schema update >> appears immediately from other threads? >> > >When a database connection has a read transaction open, it continues >to see a snapshot of the database as it existed when the read >transaction was first opened. Outside changes to the database, >including schema changes, are invisible to the connection holding the >transaction. This is the "I" in "ACID". > >As soon as you release the read transaction and start another, all >changes will immediately become visible. > >If you are not deliberately holding a read transaction open, perhaps >you are doing so accidentally by failing to sqlite3_reset() or >sqlite3_finalize() a prepared statement. You can perhaps figure out >which statement that is by running: > > SELECT sql FROM sqlite_stmt WHERE busy; That is very interesting. We definitely don't expect a read transaction to be open at that point. This is super helpful. I'll check on this next week. Thank you! Ben On Fri, Aug 16, 2019 at 12:49 PM Ben Asher <benashe...@gmail.com> wrote: > To clarify, we add a column on our writer connection, and then "SELECT * > FROM table" on the reader connection does not include the column that was > added. > > Ben > > On Fri, Aug 16, 2019 at 11:32 AM Ben Asher <benashe...@gmail.com> wrote: > >> Hi folks! We're running (sqlite 3.27.2) into an issue where we make a >> schema update (adding a column to a table) on our writer connection, but >> then the schema update isn't immediately available on the read-only >> connections that we use on other threads, which causes a crash in our >> application (app expects the column to exist at that point). I've verified >> that the column does indeed get added, and everything works fine after >> restarting the application (i.e. all connections loaded fresh pickup the >> schema update). >> >> Is there something we need to do proactively to ensure that schema update >> appears immediately from other threads? >> >> Some notes about our setup: >> >> sqlite 3.27.2 >> Using multithread mode (SQLITE_OPEN_NOMUTEX) >> Using WAL mode >> >> Thanks! >> >> Ben >> > > > -- > Ben > -- Ben _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
