The problem I encountered is the following: After proxy regained connectivity with master - it sends all the data to master and sometimes some values are of enormous size. So if the value doesn't fit in numeric(16,4) of field value in history table that will cause an error on postgresql and zabbix seem to crash after such an error.

STATEMENT: insert into history (clock,itemid,value) values
(1222333152,57039,2116201402696920729566809079614523581888883513187920255187548513701881150912761229083068636761023595953604332
8121683934802731461179707531745324934682409728126379454099366052859610637647138178248453565087199461900288.000000)
ERROR: current transaction is aborted, commands ignored until end of transaction block

My current workaround is to change field type to numeric without any fixed scale/prescision. that helps, but numeric with arbitrary prescision is a lot slower, so I'll try to find smth else.