I need to be notified when the table is full to launch a script whis dumps this table.
Please don't top post.
You are going to need to explain the entire process is greater detail if you want help. As Raymond said while I was writing, you at least need to define how you would know that the table is "full" before you can program something to detect the same.
You mention an external system - are you dealing with a push or pull oriented synchronization?