I have noted using IB 6.01 for Wndows(2000 or NT), the next problem:
If I issue a massive deletion of records from a table or several tables,
often IBServer stays using CPU in 100%, for many time(hours) after complete
the sql command. During this time, it no more accept whichever connections
from clients and stops to server all others client requests.

After some time, all come back to normal.

Is this a normal behaviour?

Thanks,

Luiz.