Fabien COELHO <coe...@cri.ensmp.fr> writes: >>> Is a connection per transaction really a sane case to consider?
>> Yes, I would think. This case reveals the connection overhead. We >> already are able to handle the simple query cases. Why not for >> extended query cases? > Probably it can be made to work, but it is much less useful to prepare a > statement which is known to be needed just once, so I think it would be > fine to simply forbid "-M prepared" and "-C" together. It's certainly a bug that the combination of the switches doesn't work, and I already fixed it (47211af17a). My question was more towards whether -C is a useful benchmarking option at all. I cannot imagine a situation in which, if someone said "I'm doing only one transaction per session, and I have a performance problem", I would not answer "yes, and you just explained why". What I found out when I looked into it was that pgbench had simply failed to consider *at all* whether it needed to reset any state when dropping a connection and replacing it with a new one. That's a really fundamental problem, even if the only symptom we've found so far is "-M prepared" not working. And it's been there since -C was invented, AFAICT. The fact that the bug went undetected this long says a lot about the amount of real-world use the switch gets. So I think it's fair to consider whether we should not eliminate a whole class of future bugs by removing a switch that gets no use. regards, tom lane -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers