On Mon, Oct 21, 2019 at 12:24 PM Pavel Stehule <pavel.steh...@gmail.com> wrote: > > po 21. 10. 2019 v 8:38 odesÃlatel Amit Kapila <amit.kapil...@gmail.com> > napsal: >> >> > If we don't wait in TerminateOtherDBBackends, then probably there should >> > be necessary some cycles inside CountOtherDBBackends. I think so code like >> > is correct >> > >> > 1. send SIGTERM to target processes >> > 2. put some time to processes for logout (100ms) >> > 3. check in loop (max 5 sec) on logout of all processes >> > >> > Maybe my feeling is wrong, but I think so it is good to wait few time >> > instead to call CountOtherDBBackends immediately - the first iteration >> > should to fail, and then first iteration is useless without chance on >> > success. >> > >> >> I think the way I am suggesting by skipping the second step will allow >> sleeping only when required. Consider a case where there are just one >> or two sessions connected to the database and they immediately exited >> after the signal is sent. In such a case you don't need to sleep at >> all whereas, under your proposal, it will always sleep. In the case >> where a large number of sessions are present and the first 100ms are >> not sufficient, we anyway need to wait dynamically. So, I think the >> second step not only looks odd but also seems to be redundant. > > > I checked the code, and I think so calling CountOtherDBBackends from > TerminateOtherDBBackends is not good idea. CountOtherDBBackends should be > called anywhere, TerminateOtherDBBackends only with FORCE flag. So I wouldn't > to change code. >
Sorry, but I am not able to understand the reason. Are you worried about the comments atop CountOtherDBBackends which says it is used in Drop Database and related commands? > But I can (and I have not any problem with it) remove or significantly > decrease sleeping time in TerminateOtherDBBackends. > > 100 ms is maybe very much - but zero is maybe too low. If there will not be > any time between TerminateOtherDBBackends and CountOtherDBBackends, then > probably CountOtherDBBackends hit waiting 100ms. > > What about only 5 ms sleeping in TerminateOtherDBBackends? > I am not completely sure about what is the most appropriate thing to do, but I favor removing sleep from TerminateOtherDBBackends. OTOH, there is nothing broken with the logic. Anyone else wants to weigh in here? -- With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com
