On 11 August 2016 at 10:18, Shay Rojansky <r...@roji.org> wrote: > > > On Thu, Aug 11, 2016 at 1:22 PM, Vladimir Sitnikov < > sitnikov.vladi...@gmail.com> wrote: > > 2) The driver can use safepoints and autorollback to the good "right >> before failure" state in case of a known failure. Here's the >> implementation: https://github.com/pgjdbc/pgjdbc/pull/477 >> > As far as I can remember, performance overheads are close to zero (no >> extra roundtrips to create a safepoint) >> > > What? Do you mean you do implicit savepoints and autorollback too? How > does the driver decide when to do a savepoint? Is it on every single > command? If not, commands can get lost when an error is raised and you > automatically roll back? If you do a savepoint on every single command, > that surely would impact performance even without extra roundtrips...? > > You seem to have a very "unique" idea of what a database driver should do > under-the-hood for its users. At the very least I can say that your concept > is very far from almost any database driver I've seen up to now (PostgreSQL > JDBC, psycopg, Npgsql, libpq...). I'm not aware of other drivers that > implicitly prepare statements, and definitely of no drivers that internally > create savepoints and roll the back without explicit user APIs. At the very > least you should be aware (and also clearly admit!) that you're doing > something very different - not necessarily wrong - and not attempt to > impose your ideas on everyone as if it's the only true way to write a db > driver. >
A number of other drivers default to this behaviour, including at least MS-SQL and Oracle. psqlODBC also supports this behaviour with statement rollback mode. And obviously PostgreSQL JDBC which Vladimir is referring to. Dave Cramer da...@postgresintl.com www.postgresintl.com
