Steps to reproduce:

1. Try to add a column to Item history widget on a system with 2000+ discovered hosts. Hosts should contain items.

Result:

PHP error log:

PHP Fatal error:  Allowed memory size of 134217728 bytes exhausted (tried to allocate 20480 bytes) in /home/test/work/review/7.0/ui/include/classes/api/CRelationMap.php

Expected:
No errors.