Add more information about avoiding Linux OOM killer.

by Toru SHIMOGAKI

diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index 57e46927107057619311f54dc8e7bdc1b065c2bf..1e2b5adb300d01c3ee89a4921c56a2d2fa94d642 100644 (file)
--- a/doc/src/sgml/runtime.sgml
+++ b/doc/src/sgml/runtime.sgml
@@ -1,4 +1,4 @@
-
+
 
 
  Operating System Environment
@@ -1201,15 +1201,21 @@ Out of Memory: Killed process 12345 (postgres).
 
    
     One way to avoid this problem is to run
-    PostgreSQL
-    on a machine where you can be sure that other processes will not
-    run the machine out of memory.
+    PostgreSQL on a machine where you can
+    be sure that other processes will not run the machine out of
+    memory.  If memory is tight, increasing the swap space of the
+    operating system can help avoiding the problem, because the
+    out-of-memory (OOM) killer is invoked whenever physical memory and
+    swap space are exhausted.
    
 
    
-    On Linux 2.6 and later, a better solution is to modify the kernel's
-    behavior so that it will not overcommit memory.  This is
-    done by selecting strict overcommit mode via sysctl:
+    On Linux 2.6 and later, an additional measure is to modify the
+    kernel's behavior so that it will not overcommit memory.
+    Although this setting will not prevent the OOM killer from
+    invoking altogether, it will lower the chances significantly and
+    will therefore lead to more robust system behavior.  This is done
+    by selecting strict overcommit mode via sysctl:
 
 sysctl -w vm.overcommit_memory=2