After ZBXNEXT-1689 to return the values for the lastvalue and lastclock properties item.get needs to perform a separate request to the history table. That means that unnecessary use of output extend may significantly impact performance.

The following places in the frontend must be corrected to not use output extend for item.get:

history.php
popup_trexpr.php
configuration.screen.constructor.edit.php

CApplication::massAdd()
CDiscoveryRule::copyGraphPrototypes()
CGraph::validateItems()
CGraphPrototype::validateCreate()
CGraphPrototype::validateUpdate()
CItem::delete()

CScreenClock::get()
CScreenHistory::__construct()

We should also check if there are other places with this problem.