Improve memory usage when rebuilding a catalog

CHANGES.rst

@@ -4,6 +4,7 @@ Changelog
 2.5.0 (unreleased)
 ------------------
 
+- #2387 Improve memory usage when rebuilding a catalog
 - #2386 Add dynamic search index lookup for referencewidget and added default catalog metadata columns
 - #2385 Fix referencefield dependencies in sample add
 - #2384 Fix reference widget lookups

src/senaite/core/catalog/base_catalog.py

@@ -150,8 +150,18 @@ def log_progress(self):
                         .format(self.progress_counter, self.id))
 
         if self.progress_counter % 10000 == 0:
+            logger.info("Creating transaction savepoint after {} objects"
+                        .format(self.progress_counter))
             transaction.savepoint(optimistic=True)
 
+    def deactivate_object(self, obj):
+        """Deactivate the object to save memory
+        """
+        try:
+            obj._p_deactivate()
+        except AttributeError:
+            pass
+
     @security.protected(ManageZCatalogEntries)
     def clearFindAndRebuild(self):
         """Considers only mapped types when reindexing the whole catalog
@@ -176,6 +186,8 @@ def indexObject(obj, path):
                 if self.is_obj_indexable(obj, portal_type, mapped_types):
                     self._reindexObject(obj, idxs=idxs)  # bypass queue
                     self.log_progress()
+                # flush object from memory
+                self.deactivate_object(obj)
             except TypeError:
                 # Catalogs have 'indexObject' as well, but they
                 # take different args, and will fail