a mysqldump causes all other queries to be queued super slow. Any clue what is going on?

[Andres Salazar]

Hello,

Everytime i run a mysqldump (mysql-server-5.0.77) all the other
legitimate queries that are ocurring at that time pretty much sleep
and build up in the processlist untill I either stop the dump or wait
for it finish. The moment i do either one i can have about 8-15
queries waiting they all free up immediately.

What could be causing this? I know there might be many factors
involved but Id like to get some clues as to where to look.

Thanks

Andres