Zabbix Server doesn't raise an action of events that have duration 0 sec.

This applies for logfiles were several matches appears within one second. For these no warning messages is raised.

The trigger used in example:

{hostname:trap.matchSCG[unsuccessful]. count( 600 ) }

=1

This should only sent a warning for the first appearence of match within a 10 minutes interval. This trigger works if single matches appears or there's a delay between the matches > 1sec.

zabbix event log:
of 2009.Jun.15 13:42:47 Logwatch - Match "unsuccessful" PROBLEM Warning 0s No -

As soon as count(600) returns 2 within the same second no action is sent.