gdb debugging with postgres

I am trying to attach a postgres process to gdb, Since I am using only 1 client , I am using the script give by Tom Lane posted in the mailing list.

I started running the client by following command psql test where test is my database.

But When I am running that script I am getting two client processes.

Could any one tell me what is checkpointer process and is there any way of running the script without that process.

Thank you,

K.Ravikiran