We started to encounter a weird issue with one of the Zabbix internal processes. The zabbix history syncer process started to go above 50% and at times spikes all the way to 100%. We notice that when that happens, the zabbix queue backs up immensely. We also notice that the zabbix server and zabbix db server are barely breaking a sweat in terms of cpu load average and overall mem usage. They are on blade servers with 16 cpu cores 16/32 gigs of ram.

We tried bumping up the cache sizes, different poller starter counts. Issue continues to occur.
We are running Zabbix 2.0.3 and postgres 9.1.4.
Attached is the zabbix_server, postgres configuration files, snapshot of zabbix_queue, snapshot of zabbix history syncer graph.