Nagios algorithms and architecture

[elif]

I am looking for documents describing the core of Nagios.

I mean architecture and algorithms of the Nagios "Event" module.

1. How does the nagios mechanism checking the service?
2. to make the the change from Soft-State to Hard-State how Nagios check it? I can't believe that nagios reads the all table of nagios.servicestatus by SQL query(select * from) every time..
3. It supposed to be "real time" event, so the time the event occurs and shows should be as fast as possible to notify - how this works on noagios?
If you can give me documents that describe all that I will be grateful.

Thank!
Eli

[Box293]

1. How does the nagios mechanism checking the service?

This might help: https://assets.nagios.com/downloads/nag ... ios-XI.pdf

2. to make the the change from Soft-State to Hard-State how Nagios check it? I can't believe that nagios reads the all table of nagios.servicestatus by SQL query(select * from) every time..

/usr/local/nagios/var/status.dat and /usr/local/nagios/var/retention.dat

3. It supposed to be "real time" event, so the time the event occurs and shows should be as fast as possible to notify - how this works on noagios?
If you can give me documents that describe all that I will be grateful.

https://assets.nagios.com/downloads/nag ... tions.html