> > I am not familiar with the python library, but that looks correct > > to me. You can always test it by adding a sleep between your two > > queries and modifying the database from a console connection > > during the sleep. > > > Note that I'm assuming your 5 queries are all read-only selects. > > If you're modifying data during your queries, and another > > concurrent database connection modifies the same data during your > > transaction, the later modifications will fail under serializable > > isolation. > > Which one will fail? the second query or the serializable > transaction. > > My understanding was that the serializable transaction will fail. > Yes, serializable transactions fail if they attempt to modify data which has changed since the beginning of the transaction. If the OP's ajax call kicks off 5 queries in a serializable transaction, there is the potential for failure if two ajax calls initiate simultaneous serializable transactions modifying data.
