kill - postgresql

Hi guys.

I was was designing a simple database in postgresql. I wrote a perl function in postgresql and execute it. suddenly i saw that it is running in an infinite loop. After i stopped executing of the query, i saw that CPU is in 90%+ load. I looked at process list and there it was. postgresql was eating CPU :D.
I tried to restart the postgresql service but it says FAILED. I tried to kill the postgresql process again failed(it shows that it is killed but the postmaster process was in the list) then i tried to reboot but again failed(waiting for long time) so i reboot it manually. Anybody could explain what is happening?

I am using fedora 14.

Often runaway RDBMS commands have to be killed by another session, as they do not come back to the client socket for data until they finish. It helps to have an extra client open. Sometimes you have to be dba/sa to kill the bad session. Sometimes the RDBMS can be configured with limits so they clear themselves eventually.