> I can see a couple possible downsides: (a) the library might have some

> weird behavior across fork boundaries; (b) the additional memory space
> that has to be duplicated into child processes will cost something per
> child launch, even if the child never uses it.  But these are only
> arguments that it might not *always* be a prudent thing to do, not that
> we shouldn't give the DBA the tool to do it if he wants.  So fire away.

Here is a patch for the above, including a documentation update. It
creates a new GUC variable "preload_libraries", that accepts a list in
the form:

   preload_libraries = '$libdir/mylib1:initfunc,$libdir/mylib2'

If ":initfunc" is omitted or not found, no initialization function is
executed, but the library is still preloaded. If "$libdir/mylib" isn't
found, the postmaster refuses to start.

In my testing with PL/R, it reduces the first call to a PL/R function
(after connecting) from almost 2 seconds, down to about 8 ms.

Joe Conway

src/backend/utils/misc/guc.c

@@ -5,7 +5,7 @@
  * command, configuration file, and command line options.
  * See src/backend/utils/misc/README for more information.
  *
- * $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.116 2003/03/04 21:51:21 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/misc/guc.c,v 1.117 2003/03/20 04:51:44 momjian Exp $
  *
  * Copyright 2000 by PostgreSQL Global Development Group
  * Written by Peter Eisentraut <peter_e@gmx.net>.
@@ -60,6 +60,7 @@ extern int	CheckPointTimeout;
 extern bool autocommit;
 extern int	CommitDelay;
 extern int	CommitSiblings;
+extern char *preload_libraries_string;
 
 #ifdef HAVE_SYSLOG
 extern char *Syslog_facility;
@@ -814,6 +815,12 @@ static struct config_string
 		"C", locale_time_assign, NULL
 	},
 
+	{
+		{"preload_libraries", PGC_POSTMASTER, GUC_LIST_INPUT | GUC_LIST_QUOTE},
+		&preload_libraries_string,
+		"", NULL, NULL
+	},
+
 	{
 		{"regex_flavor", PGC_USERSET}, &regex_flavor_string,
 		"advanced", assign_regex_flavor, NULL