zabbix stopped sending e-mails. empty actions in events

[ShivaS]

Hello,

We have zabbix 2.0.10 (running zabbix since 1.0)

Suddenly zabbix stopped sending e-mails. Everything in Events -> "Message actions" remains empty.
zabbix can work that way forever. Once zabbix_server is restarted, all mails that should have been sent are sent, almost everything. We get a bunch of monitors we had to get before. And then after a few minutes no e-mails again. Triggers are working but all mails stop working again. nothing in mailq/mysql errors, web errors, nowhere. So we now checking web interface triggers once a few minutes to check for bad things.

We have around 50k items (triggers) and mails should arrive all the time.
Setting zabbix in debug mode is a real eyes torture..can't understand much. So at this moment we are trying to figure out what happened based on audit logs but already checked twice everything/fixed/disabled/deleted and still no idea...

Any help/inputs are appreciated!

[ShivaS]

Just to inform that I found the problem.
We had some action to send remote traceroute on some service failure, so we'll know (among other details) what is the trace to external resource at that very moment.
lately we had that monitoring going up/down because of some "external resource" works and looks like action queue was full of remote commands that haven't been sent/executed yet.
Disabled that action, disabled hosts it should have sent the remote commands to. Watched for an hour in zabbix_server.log notifications about cancelling actions, and then all emails started to work. Enabled hosts and now everything runs smooth as before, without that action of course.

It was hard to find that problem. Is there any table in DB that can give me more information on queued actions?