[Summary]

In Zabbix Proxy environment, history value is always missing when Zabbix server is stopped. The missing value is only one after stop Zabbis server.

Please see screenshot "Latest 500 value"

[Reproduce]

1. Setup agent, server, proxy
2. Add proxy server
3. Add host using above proxy
4. Add icmpping item (60 sec interval) to above host
5. Wait after receive new value
6. Stop Zabbix server
7. Wait 5 minutes
8. Start Zabbix server

The value at "2012.Feb.21 09:00:22" (unixtime : 1329782482) is missing. This value is exists on Proxy database, but not exists on Server database.

However, there is strange value at "2012.Feb.21 09:05:32" (unixtime : 1329782732). This value is not exists on Proxy database, but exists on Server database.

Please see zabbix_server_debug.log and zabbix_proxy_debug.log.
Proxy send 1329782482 data to Server, and Server receive the data. but Server store the data with 1329782732 timestamp.

[history value on Zabbix Proxy database]

1. mysql -uroot zabbix_proxy -e 'select clock, from_unixtime(clock), value from proxy_history order by clock desc;'
   -------------------------------------

   clock

   from_unixtime(clock)

   value

   -------------------------------------

   1329782962	2012-02-21 09:09:22	1
   1329782902	2012-02-21 09:08:22	1
   1329782842	2012-02-21 09:07:22	1
   1329782782	2012-02-21 09:06:22	1
   1329782722	2012-02-21 09:05:22	1
   1329782662	2012-02-21 09:04:22	1
   1329782602	2012-02-21 09:03:22	1
   1329782542	2012-02-21 09:02:22	1
   1329782482	2012-02-21 09:01:22	1
   1329782422	2012-02-21 09:00:22	1
   1329782362	2012-02-21 08:59:22	1
   1329782302	2012-02-21 08:58:22	1
   1329782242	2012-02-21 08:57:22	1

   -------------------------------------

[history value on Zabbix Server database]

1. mysql -uroot zabbix -e 'select clock, from_unixtime(clock), value from history_uint order by clock desc'
   -------------------------------------

   clock

   from_unixtime(clock)

   value

   -------------------------------------

   1329782962	2012-02-21 09:09:22	1
   1329782902	2012-02-21 09:08:22	1
   1329782842	2012-02-21 09:07:22	1
   1329782782	2012-02-21 09:06:22	1
   1329782732	2012-02-21 09:05:32	1
   1329782722	2012-02-21 09:05:22	1
   1329782662	2012-02-21 09:04:22	1
   1329782602	2012-02-21 09:03:22	1
   1329782542	2012-02-21 09:02:22	1
   1329782422	2012-02-21 09:00:22	1
   1329782362	2012-02-21 08:59:22	1
   1329782302	2012-02-21 08:58:22	1
   1329782242	2012-02-21 08:57:22	1

   -------------------------------------