> Paul wrote: > > I can check whether user_version matches magic number without transaction. > > No. Executing "PRAGMA user_version" will start an automatic transaction > if you didn't already start an explicit one. > > > Only when user_version does not match magic number I start transaction. > > This will never be faster than just starting a transaction explicitly > and checking the version once. > > > The only thing I am worried about is whether > > > > pragma user_version=n; > > > > respects transactions and will be rolled back automatically in case > > if something happens between that statement and COMMIT. > > Please have a look at this sentence, which you quoted in your mail: > >> Please note that *all* accesses to the database file are done with > >> transactions, including reading and writing the user_version value. >
I suspect that no, not all accesses to the database file are done using transactions. What about read-only databases? Moreover, what about read-only medium? I am actually worried not of transaction per se but of its impact on HDD. My databases must be opened as fast as possilbe. And in 95% of cases all executed queries are SELECTs. I don't want sqlite to write anything to disk when, within single database session, data is only extracted and no modifications to database are made. Correct me if I have a wrong model of transaction in mind. Maybe sqlite does not write a byte to disk if inside a transaction there are only selects? _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
