* Tom Lane: >> IIRC, the idea is to get the machine out of OOM land with one killed >> process, even if it causes dependent processes to fail. > > You're just parroting the reasoning given on the cited webpage, which > is loony because it takes no account whatsoever of actual practice.
Oops, I hadn't actually read it (I can't reach the Web from this terminal). > Postgres is hardly the only daemon for which killing the parent results > in far worse DOS than not doing so. sendmail, sshd, inetd, and mysqld > are examples that come to mind immediately, and I am fairly sure that > it's true for apache as well. Historically, the OOM killer was mainly there to avoid a total lock-up or straight reboot on single-user machines with text-mode console and the occassional broken shell script. For example, it used to kill the X server, too. Anyway, a dead SSH session or database server is less of a DoS than a lock-up due to the OOM killer's inability to recover resources in a reasonable time frame. (I'd need to check if it prefers killing the main sshd daemon. That would be rather inconvenient.) And let me repeat: If some shell script à la for x in *; do foo $x; done is causing the trouble, you need to kill the parent (the shell) to bring the system back. Killing foo brings only very short-term relief. Fortunately, it's possible to turn off overcommitment nowadays, so it's not such a huge issue anymore (for me, at least). Some applications are still not fully compatible with this mode (SBCL, for instance, and the Sun JVM doesn't perform as well as it could, either), but there are astonishingly few problems with vm.overcommit_memory=2. -- Florian Weimer <[EMAIL PROTECTED]> BFK edv-consulting GmbH http://www.bfk.de/ Kriegsstraße 100 tel: +49-721-96201-1 D-76133 Karlsruhe fax: +49-721-96201-99 ---------------------------(end of broadcast)--------------------------- TIP 1: 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
