--- a/schema/gemma.sql	Wed Jul 31 19:08:53 2019 +0200
+++ b/schema/gemma.sql	Thu Aug 01 17:07:01 2019 +0200
@@ -883,9 +883,13 @@
     tmp RECORD;
 BEGIN
     FOR tmp IN
-        SELECT * FROM import.track_imports WHERE import_id = imp_id AND NOT deletion
+        SELECT relation, array_agg(key) AS keys
+            FROM import.track_imports
+            WHERE import_id = imp_id AND NOT deletion
+            GROUP BY relation
     LOOP
-        EXECUTE format('DELETE FROM %s WHERE id = $1', tmp.relation) USING tmp.key;
+        EXECUTE format('DELETE FROM %s WHERE id = ANY($1)', tmp.relation)
+            USING tmp.keys;
     END LOOP;
 END;
 $$