Re: Testing of MVCC

Greg Stark <gsstark(at)mit(dot)edu> writes:
> So why bother with driving multiple invocations of psql under
> Expect. Just use DBD::Pg to open as many connections as you want and
> issue whatever queries you want.

The bit that I think is missing in DBI is "issue a command and don't
wait for the result just yet". Without that, you cannot for instance
stack up several waiters for the same lock, as you might wish to do to
verify that they get released in the correct order once the original
lock holder goes away. Or stack up some conflicting waiters and check
to see if deadlock is detected when it should be ... or contrariwise,
not signalled when it should not be. There's lots of stuff you can
do that isn't exactly probing for race conditions, yet would be awfully
nice to check for in a routine test suite.

I might be wrong though, not being exactly a DBI guru ... can this
sort of thing be done?

regards, tom lane