diff --git a/app/models/manager_refresh/save_collection/saver/base.rb b/app/models/manager_refresh/save_collection/saver/base.rb
index 4e56cada7ce..160ed3fde6f 100644
--- a/app/models/manager_refresh/save_collection/saver/base.rb
+++ b/app/models/manager_refresh/save_collection/saver/base.rb
@@ -250,26 +250,39 @@ def assign_attributes_for_create!(hash, create_time)
         assign_attributes_for_update!(hash, create_time)
       end
 
-      def unique_index_columns
-        return @unique_index_columns if @unique_index_columns
+      def unique_indexes
+        @unique_indexes_cache if @unique_indexes_cache
 
-        if model_class.respond_to?(:manager_refresh_unique_index_columns)
-          return @unique_index_columns = model_class.manager_refresh_unique_index_columns
-        end
-
-        unique_indexes = model_class.connection.indexes(model_class.table_name).select(&:unique)
-        if unique_indexes.count > 1
-          raise "Cannot infer unique index automatically, since the table #{model_class.table_name}"\
-                " of the #{inventory_collection} contains more than 1 unique index: '#{unique_indexes.collect(&:name)}'."\
-                " Please define the unique index columns explicitly on a model as a class method"\
-                " self.manager_refresh_unique_index_columns returning [:column1, :column2, etc.]"
-        end
+        @unique_indexes_cache = model_class.connection.indexes(model_class.table_name).select(&:unique)
 
-        if unique_indexes.blank?
+        if @unique_indexes_cache.blank?
           raise "#{inventory_collection} and its table #{model_class.table_name} must have a unique index defined, to"\
                 " be able to use saver_strategy :concurrent_safe or :concurrent_safe_batch."
         end
-        @unique_index_columns = unique_indexes.first.columns.map(&:to_sym)
+
+        @unique_indexes_cache
+      end
+
+      def unique_index_for(keys)
+        @unique_index_for_keys_cache ||= {}
+        @unique_index_for_keys_cache[keys] if @unique_index_for_keys_cache[keys]
+
+        # Find all uniq indexes that that are covering our keys
+        uniq_key_candidates = unique_indexes.each_with_object([]) { |i, obj| obj << i if (keys - i.columns.map(&:to_sym)).empty? }
+
+        if @unique_indexes_cache.blank?
+          raise "#{inventory_collection} and its table #{model_class.table_name} must have a unique index defined "\
+                "covering columns #{keys} to be able to use saver_strategy :concurrent_safe or :concurrent_safe_batch."
+        end
+
+        # Take the uniq key having the least number of columns
+        @unique_index_for_keys_cache[keys] = uniq_key_candidates.min_by { |x| x.columns.count }
+      end
+
+      def unique_index_columns
+        return @unique_index_columns if @unique_index_columns
+
+        @unique_index_columns = unique_index_for(unique_index_keys).columns.map(&:to_sym)
       end
 
       def supports_sti?
diff --git a/app/models/manager_refresh/save_collection/saver/sql_helper.rb b/app/models/manager_refresh/save_collection/saver/sql_helper.rb
index 796aaba166a..f009071b7a8 100644
--- a/app/models/manager_refresh/save_collection/saver/sql_helper.rb
+++ b/app/models/manager_refresh/save_collection/saver/sql_helper.rb
@@ -34,8 +34,11 @@ def build_insert_query(all_attribute_keys, hashes, on_conflict: nil)
               ON CONFLICT DO NOTHING
             }
           elsif on_conflict_update
+            index_where_condition = unique_index_for(unique_index_keys).where
+            where_to_sql = index_where_condition ? "WHERE #{index_where_condition}" : ""
+
             insert_query += %{
-              ON CONFLICT (#{unique_index_columns.map { |x| quote_column_name(x) }.join(",")})
+              ON CONFLICT (#{unique_index_columns.map { |x| quote_column_name(x) }.join(",")}) #{where_to_sql}
                 DO
                   UPDATE
                     SET #{all_attribute_keys_array.map { |key| build_insert_set_cols(key) }.join(", ")}
diff --git a/app/models/vm_or_template.rb b/app/models/vm_or_template.rb
index dedb1dcbd7d..789849dd4a1 100644
--- a/app/models/vm_or_template.rb
+++ b/app/models/vm_or_template.rb
@@ -294,10 +294,6 @@ def self.model_suffix
     manager_class.short_token
   end
 
-  def self.manager_refresh_unique_index_columns
-    [:ems_id, :ems_ref]
-  end
-
   def to_s
     name
   end