Index: openacs-4/packages/xotcl-request-monitor/tcl/throttle_mod-procs.tcl
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/xotcl-request-monitor/tcl/throttle_mod-procs.tcl,v
diff -u -r1.67.2.41 -r1.67.2.42
--- openacs-4/packages/xotcl-request-monitor/tcl/throttle_mod-procs.tcl	20 Apr 2021 09:37:11 -0000	1.67.2.41
+++ openacs-4/packages/xotcl-request-monitor/tcl/throttle_mod-procs.tcl	22 Apr 2021 12:37:01 -0000	1.67.2.42
@@ -1698,11 +1698,17 @@
   # :log "--t [info exists :context_initialized] url=[ns_conn url]"
   if {[info exists :context_initialized]} return
 
-  set url [string trimright [ns_conn url] "/"]
-  if {$url eq ""} {
-    set url "/"
+  #
+  # In case, the connection got terminated due to e.g. invalid URLs
+  # earlier, fall back to URL "/" to avoid hard DB errors resulting
+  # from the sitemap lookup of the URL.
+  #
+  if {[ns_conn isconnected]} {
+    set :url [ns_conn url]
+    ns_log notice "URL <${:url}> invalid? [regexp  {[^[:print:]]} ${:url}]"
+  } else {
+    set :url /
   }
-  set :url $url
   set :method [ns_conn method]
 
   set :community_id 0