--- loncom/lonnet/perl/lonnet.pm	2016/03/02 14:14:14	1.1301
+++ loncom/lonnet/perl/lonnet.pm	2016/03/02 18:23:17	1.1302
@@ -1,7 +1,7 @@
 # The LearningOnline Network
 # TCP networking package
 #
-# $Id: lonnet.pm,v 1.1301 2016/03/02 14:14:14 raeburn Exp $
+# $Id: lonnet.pm,v 1.1302 2016/03/02 18:23:17 raeburn Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -10341,7 +10341,7 @@ sub resdata {
         if ($item->[1] eq 'course') {
             if ((ref($recurseup) eq 'ARRAY') && (ref($recursed) eq 'SCALAR')) {
                 unless ($$recursed) {
-                    @{$recurseup} = &get_map_hierarchy($mapp);
+                    @{$recurseup} = &get_map_hierarchy($mapp,$courseid);
                     $$recursed = 1;
                 }
                 foreach my $item (@${recurseup}) {
@@ -10402,6 +10402,16 @@ sub get_numsuppfiles {
 # EXT resource caching routines
 #
 
+{
+# Cache (5 seconds) of map hierarchy for speedup of navmaps display
+#
+# The course for which we cache
+my $cachedmapkey='';
+# The cached recursive maps for this course
+my %cachedmaps=();
+# When this was last done
+my $cachedmaptime='';
+
 sub clear_EXT_cache_status {
     &delenv('cache.EXT.');
 }
@@ -10592,7 +10602,6 @@ sub EXT {
 # ----------------------------------------------------- Cascading lookup scheme
 	    my $symbp=$symbparm;
 	    $mapp=&deversion((&decode_symb($symbp))[0]);
-            @recurseup=();
 	    my $symbparm=$symbp.'.'.$spacequalifierrest;
             my $recurseparm=$mapp.'___(rec).'.$spacequalifierrest;
 	    my $mapparm=$mapp.'___(all).'.$spacequalifierrest;
@@ -10764,18 +10773,29 @@ sub check_group_parms {
 }
 
 sub get_map_hierarchy {
-    my ($mapname) = @_;
-    my @recurseup = (); 
+    my ($mapname,$courseid) = @_;
+    my @recurseup = ();
     if ($mapname) {
+        if (($cachedmapkey eq $courseid) &&
+            (abs($cachedmaptime-time)<5)) {
+            if (ref($cachedmaps{$mapname}) eq 'ARRAY') {
+                return @{$cachedmaps{$mapname}};
+            }
+        }
         my $navmap = Apache::lonnavmaps::navmap->new();
         if (ref($navmap)) {
             @recurseup = $navmap->recurseup_maps($mapname);
             undef($navmap);
+            $cachedmaps{$mapname} = \@recurseup;
+            $cachedmaptime=time;
+            $cachedmapkey=$courseid;
         }
     }
     return @recurseup;
 }
 
+}
+
 sub sort_course_groups { # Sort groups based on defined rankings. Default is sort().
     my ($courseid,@groups) = @_;
     @groups = sort(@groups);