Thanks. Interesting. Hard to imagine what they were thinking when they put this code in.
--------------------------------------------------------------------------- Andrew Dunstan wrote: > The current developer docs say this: > > ------------------- > Linux has poor default memory overcommit behavior. Rather than failing if it > can not reserve enough memory, it returns success, but later fails when the > memory can't be mapped and terminates the application with kill -9. To > prevent unpredictable process termination, use: > > sysctl -w vm.overcommit_memory=3 > --------------------- > > This would be true if the kernel being used had the paranoid mode compiled > in. This is not true, AFAICS, of either the stock 2.4 kernels nor of the > latest RH kernels. It is true of 2.4.21 *with* the -ac4 (and posibly earlier > -ac*) patch. In fact, Alan's patch apparently allows tuning of the amount of > overcommitting allowed. As I read the kernel source I got from RH today > (2.4.20-19.9), doing this will in fact make the kernel freely allow > overcommiting of memory, rather than it trying in a rather unsatisfactory > way to avoid it. IOW, with many kernels the advice would make things worse, > not better - e.g. the RH source says this in mm/mmap.c: > > if (sysctl_overcommit_memory) > return 1; > > > Rather than give bad advice, it might be better to advise users (1) to run > Pg on machines that are likely to be stable and not run into OOM situations, > and (2) to check with their vendors about proper overcommit handling. > > Personally, my advice would be to avoid Linux for mission critical apps > until this is fixed, but that's just my opinion, and I'm happily developing > on Linux, albeit for something that is not mission critical. > > cheers > > andrew > > > > > ---------------------------(end of broadcast)--------------------------- > TIP 3: if posting/reading through Usenet, please send an appropriate > subscribe-nomail command to [EMAIL PROTECTED] so that your > message can get through to the mailing list cleanly > -- Bruce Momjian | http://candle.pha.pa.us [EMAIL PROTECTED] | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073 ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
