Add rudimentary section about controlling kernel's file and process limits.

diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index 1a86b5c9bb9242d9b6d6495e9576820156d53abe..81d0846e00a10394a550981c51d13c1e00d193c5 100644 (file)
--- a/doc/src/sgml/runtime.sgml
+++ b/doc/src/sgml/runtime.sgml
@@ -1,5 +1,5 @@
 
 
 
@@ -1536,7 +1536,8 @@ options "SEMMNU=120"
 
 
      
-      FreeBSD
+      FreeBSD
+      OpenBSD
       
        
         The options SYSVSHM and SYSVSEM need
@@ -1545,14 +1546,14 @@ options "SEMMNU=120"
         the option SHMMAXPGS (in pages). The following
         shows an example of how to set the various parameters:
 
-options         SYSVSHM                                                           
-options         SHMMAXPGS=4096                                                    
-options         SHMSEG=256                                                        
-                                                                                  
-options         SYSVSEM                                                           
-options         SEMMNI=256                                                        
-options         SEMMNS=512                                                        
-options         SEMMNU=256                                                        
+options         SYSVSHM
+options         SHMMAXPGS=4096
+options         SHMSEG=256
+
+options         SYSVSEM
+options         SEMMNI=256
+options         SEMMNS=512
+options         SEMMNU=256
 options         SEMMAP=256
 
        
@@ -1711,24 +1712,82 @@ set semsys:seminfo_semmsl=32
 
     
 
-    
-     
-      If your platform is not listed here, please consider
-      contributing some information.
-     
-    
    
   
 
- 
+
+  
+   Resource Limits
+
+   
+    Unix-like operating systems enforce various kinds of resource
+    limits that might interfere with the operation of your
+    Postgres server.  Of importance are
+    especially the limits on the number of processes per user, the
+    number of open files per process, and the amount of memory
+    available to a process.  Each of these have a hard
+    and a soft limit.  The soft limit is what actually
+    counts but it can be changed by the user up to the hard limit.
+    The hard limit can only be changed by the root user.  The system
+    call setrlimit is responsible for setting
+    these parameters.  The shell the built-in command
+    ulimit (Bourne shells) or
+    limit (csh) is used to control the resource
+    limits from the command line.  On BSD-derived systems the file
+    /etc/login.conf controls what values the
+    various resource limits are set to upon login.  See
+    login.conf
+    5 for details.  The relevant
+    parameters are maxproc,
+    openfiles, and datasize.
+    For example:
+
+default:\
+...
+        :datasize-cur=256M:\
+        :maxproc-cur=256:\
+        :openfiles-cur=256:\
+...
+
+    (-cur is the soft limit.  Append
+    -max to set the hard limit.)
+   
+
+   
+    Kernels generally also have an implementation-dependent
+    system-wide limit on some resources.
+    
+     
+      On Linux
+      /proc/sys/fs/file-max determines the
+      maximum number of files that the kernel will allocate.  It can
+      be changed by writing a different number into the file or by
+      adding an assignment in /etc/sysctl.conf.
+      The maximum limit of files per process is fixed at the time the
+      kernel is compiled; see
+      /usr/src/linux/Documentation/proc.txt for
+      more information.
+     
+    
+   
+
+   
+    The Postgres server uses one process
+    per connection so you should provide for at least as many processes
+    as allowed connections, in addition to what you need for the rest
+    of your system.  This is usually not a problem but if you run
+    several servers on one machine things might get tight.
+   
+
+   
+    The factory default limit on open files is often set to
+    socially friendly values that allow many users to
+    coexist on a machine without using an inappropriate fraction of
+    the system resources.  If you run many servers on a machine this
+    is perhaps what you want, but on dedicated servers you may want to
+    raise this limit.
+   
+  
 
  
 
@@ -1819,19 +1878,18 @@ set semsys:seminfo_semmsl=32
    can be started with the argument -l (ell) to enable
    SSL connections. When starting in SSL mode, the postmaster will look
    for the files server.key and server.crt in
-   the data directory (pointed to by PGDATA).
-    These files should contain the server private key
+   the data directory.  These files should contain the server private key
    and certificate respectively. These files must be set up correctly
    before an SSL-enabled server can start. If the private key is protected
    with a passphrase, the postmaster will prompt for the passphrase and will
-   not start until it has been provided.
+   not start until it has been entered.
   
 
   
    The postmaster will listen for both standard and SSL connections
    on the same TCP/IP port, and will negotiate with any connecting
    client whether or not to use SSL.
-    See 
+   See 
    about how to force on the server side the use of SSL for certain
    connections.
   
@@ -1843,27 +1901,27 @@ set semsys:seminfo_semmsl=32
    by a CA (either one of the global CAs or a local one) should be used in 
    production so the client can verify the servers identity. To create
    a quick self-signed certificate, use the following OpenSSL command:
-    
-     openssl req -new -text -out cert.req
-    
+
+openssl req -new -text -out cert.req
+
    Fill out the information that openssl asks for. Make sure that you enter
    the local host name as Common Name; the challenge password can be
-   left blank. The script will generate a key that is passphrase protected;
-   it will not accept a pass phrase that is less than four characters long.
-   To remove the passphrase (as you must if you want automatic start-up of
-   the postmaster), run the commands
-    
-     mv privkey.pem cert.pem.pw
-     openssl rsa -in cert.pem.pw -out cert.pem 
-    
+   left blank. The script will generate a key that is passphrase protected;
+   it will not accept a pass phrase that is less than four characters long.
+   To remove the passphrase (as you must if you want automatic start-up of
+   the postmaster), run the commands
+
+mv privkey.pem cert.pem.pw
+openssl rsa -in cert.pem.pw -out cert.pem 
+
    Enter the old passphrase to unlock the existing key. Now do
-    
-     openssl req -x509 -in cert.req -text -key cert.pem -out cert.cert
-     cp cert.pem $PGDATA/server.key
-     cp cert.cert $PGDATA/server.crt
-    
+
+openssl req -x509 -in cert.req -text -key cert.pem -out cert.cert
+cp cert.pem $PGDATA/server.key
+cp cert.cert $PGDATA/server.crt
+
    to turn the certificate into a self-signed certificate and to copy the
-   key and certificate to where the postmaster will look for them.
+   key and certificate to where the postmaster will look for them.