Keep in mind that each database handle is using its own
entirely
independent transaction. If you use db_transaction, it will not
work across multiple database handles from multiple pools (or even
from same pool, I think), but it won't throw a warning or error
either. It will just not enforce a transaction, because it can't.
I have personally never seen even one case where using two
database handles and pools at once via db_foreach was actually a good
idea. Don, do such cases exist at all in real life? Maybe OpenACS
should ship a default AOLserver config file that allows use of only
one database pool at a time?
After all, people can always configure a 2nd, 3rd, 4th, or Nth pool if
they really want to, and know what they're doing. The automatic
transparent grabbing of additional independent database handles via
db_foreach (introduced in or shortly before ACS 4.0) always seemed
like a dangerous feature to me, most especially because of the way it
breaks transactional semantics, which no one new to OpenACS is going
to realize. I suspect newbies would be better off just getting an
error message...
Hm, I wonder if any other database drivers (e.g., Oratcl, SQLite) let
you issue multiple concurrent SQL statements which are all part of the
same transaction, or if that's even possible with the Oracle OCI or
PostgreSQL C libraries. Anybody know?
