pg_dump and very slow database

Greetings,

I started a process last night that is reading records from one table,
applying some business rules (validation) and then moving some data to
another table.

I had a cron job which I forgot about that ran last night too. This
simply executes pg_dump :

/usr/local/pgsql/bin/pg_dump -U postgres -b -f
/home/backup/postgres_db/mydatabase.pgd -Fc mydatabase

The backup has been running for more than 140 minutes, according to
"ps". The processing of the records is still going but it is very slow
compared to when I first started it. I suspect there to be a problem
with running my process and this backup running at the same time. The
"locks" tab on the pgAdmin Server Status screen is full of locks for the
pg_dump command.

I do not have to have this backup done now, I can run it later today
manually.

Is it safe for me to just "kill -9" the pg_dump process? Or is there a
more graceful way to stop the pg_dump process.

Thanks in advance,
James