formdef storage: don't rewrite function uselessly (#64503)

wcs/sql.py

@@ -864,12 +864,7 @@ def recreate_trigger(formdef, cur, conn):
     formed_name_quotedstring = psycopg2.extensions.QuotedString(formdef.name)
     formed_name_quotedstring.encoding = 'utf8'
     formdef_name = formed_name_quotedstring.getquoted().decode()
-    cur.execute(
-        '''
-CREATE OR REPLACE FUNCTION {trg_fn_name}()
-RETURNS trigger
-LANGUAGE plpgsql
-AS $$
+    trigger_code = '''
 BEGIN
     IF TG_OP = 'DELETE' THEN
         DELETE FROM wcs_all_forms WHERE formdef_id = {formdef_id} AND id = OLD.id;
@@ -926,18 +921,34 @@ BEGIN
         RETURN NEW;
     END IF;
 END;
-$$;
-    '''.format(
-            trg_fn_name=get_formdef_trigger_function_name(formdef),
-            category_id=category_value,  # always valued ? need to handle null otherwise.
-            formdef_id=formdef.id,
-            geoloc_base_x=geoloc_base_x_query,
-            geoloc_base_y=geoloc_base_y_query,
-            formdef_name=formdef_name,
-            criticality_levels=criticality_levels,
-            endpoint_status=endpoint_status_filter,
-        )
+'''.format(
+        category_id=category_value,  # always valued ? need to handle null otherwise.
+        formdef_id=formdef.id,
+        geoloc_base_x=geoloc_base_x_query,
+        geoloc_base_y=geoloc_base_y_query,
+        formdef_name=formdef_name,
+        criticality_levels=criticality_levels,
+        endpoint_status=endpoint_status_filter,
     )
+    cur.execute(
+        '''SELECT prosrc FROM pg_proc
+            WHERE proname = '%s'
+        '''
+        % get_formdef_trigger_function_name(formdef)
+    )
+    function_row = cur.fetchone()
+    if function_row is None or function_row[0] != trigger_code:
+        cur.execute(
+            '''
+CREATE OR REPLACE FUNCTION {trg_fn_name}()
+RETURNS trigger
+LANGUAGE plpgsql
+AS $${code}$$;
+        '''.format(
+                trg_fn_name=get_formdef_trigger_function_name(formdef),
+                code=trigger_code,
+            )
+        )
 
     trg_name = get_formdef_trigger_name(formdef)
     cur.execute(