Since upgrade from 3.4.4. to 3.4.6 history syncer generates bigger load (see screenshots)
server was restarted at 16:21

Screenshot attached

In server logs there are slowlog infor about queries like:

"select distinct itemid from trends_uint where clock>=1516057200 and (itemid between 108506 and 108533 or itemid between 108839 and 108866 or itemid in (25806,26526,33366,49452,50826,52806,52866,55326,59318,59614,61686,68286,68706,70026,70086,70116,70146,70272,78145,80732,82761,82767,102354,102359,108501,108502,108503,108535,108834,108835,108836,108868,174126,186126,193236,200754,201066,244731,255343,300306,312666))"

besides zabbix upgrade no changes was made on the server and storage