Index: openacs-4/packages/search/sql/postgresql/search-packages-create.sql
===================================================================
RCS file: /usr/local/cvsroot/openacs-4/packages/search/sql/postgresql/search-packages-create.sql,v
diff -u -N -r1.7 -r1.7.6.1
--- openacs-4/packages/search/sql/postgresql/search-packages-create.sql	30 Mar 2013 18:50:29 -0000	1.7
+++ openacs-4/packages/search/sql/postgresql/search-packages-create.sql	1 Mar 2021 18:20:47 -0000	1.7.6.1
@@ -1,35 +1,47 @@
 -- Search Observer Package
 --
--- @cvs-id $Id$ 
+-- @cvs-id $Id$
 
 
 
 --
 -- procedure search_observer__enqueue/2
 --
+select define_function_args('search_observer__enqueue','object_id,event');
+
 CREATE OR REPLACE FUNCTION search_observer__enqueue(
    p_object_id integer,
    p_event varchar
 ) RETURNS integer AS $$
 DECLARE
 BEGIN
+    --
+    -- We see cases, where the object to be removed from the observer
+    -- queue does not exist anymore. Probably, this is due to some
+    -- race condition.
+    --
+    if p_event = 'DELETE' then
+
+      IF NOT EXISTS (select 1 from acs_objects where object_id = p_object_id) then
+         return 0;
+      end if;
+
+    end if;
+
     insert into search_observer_queue (
-	object_id,
-	event
+        object_id,
+        event
     ) values (
         p_object_id,
-	p_event
+        p_event
     );
 
     return 0;
 
 END;
 $$ LANGUAGE plpgsql;
 
-select define_function_args('search_observer__enqueue','object_id,event');
 
-
-
 --
 -- procedure search_observer__dequeue/3
 --
@@ -41,8 +53,8 @@
 DECLARE
 BEGIN
 
-    delete from search_observer_queue 
-    where object_id = p_object_id 
+    delete from search_observer_queue
+    where object_id = p_object_id
     and event = p_event
     and to_char(event_date,'yyyy-mm-dd hh24:mi:ss.us-tz') = to_char(p_event_date,'yyyy-mm-dd hh24:mi:ss.us-tz');
 
@@ -52,4 +64,3 @@
 $$ LANGUAGE plpgsql;
 
 select define_function_args('search_observer__dequeue','object_id,event_date,event');
-