Under some circumstances it is possible that zabbix server logs are populated with messages that value cache is fully used, however internal metrics and charts for value cache does not show any deviations and it remains on the same level before and after. The debug patch for Value Cache to be able troubleshoot, find root cause and prevent it in future was already introduced in the newer versions, but the possibility of enabling it before the Value Cache enters low memory mode with a run-time command, to observe overall performance constantly is not, though it may be a great benefit in preventive debugging.

Summary: Please introduce value cache debug runtime command option