On Tue, Dec 11, 2007 at 09:23:38AM +0100, Listaccount wrote: > I don't want to start the discussion what is the rigth thing todo, Then you shouldn't ask here. The manual was changed to say what it does after considerable community discussion. In my view, the Linux kernel's behaviour is completely unacceptable, and exactly the sort of amateur design foolishness that people are complaining about when they say Linux is a toy. > What i would like to see in the documentation is the easy hint to > check if you get i trouble with this setting so one can prepare. >From the point of view of Postgres, "getting in trouble" means "postmaster shot in head by surprise." If you feel otherwise, then you have to learn how to tune your operating system correctly. The PostgreSQL manual is not a place for general wisdom about how to tune various kernels. I think the advice is correctly worded as it is. > A simple "see if your "CommitLimit - Commited_AS" from /proc/meminfo > come close to 0 after some uptime and if so don't use it. That's not good enough, because the case where you really get into trouble might be an unusual case. It's in fact exactly the condition where your machine is facing surprising loads where memory overcommit will bite you. So following your advice will still lead people to be surprised when their postmaster goes away because they were Slashdotted or something. > only like to see a hint how to check *before* you get in trouble. "Am I using Linux with overcommit?" would be one such check. The only reliable one. (Also, "Am I using AIX?" just in case anyone thinks this is some sort of anti-Linux bias I have. Malloc lying ranks with system sins right up there with fsync returning before the bits are on the platter.) A ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
