> 1) How could i determine what is the problem and how could i solve this problem?

Use IBAnalyst when DB is slow.

> 2) I use events. Events to cause this problem?

Very unlikely, but it depends on your application code, i.e. what
does it do on event arrival.

> 3) if i upgrade Firebird 2.1.1, this help solve the problem?

I doubt so, because I believe that the problem is in transaction
handling in your application.

SY, SD.