PGLOG problem

A simple question but since I'm not very conversant with PG if someone can help me about how to reduce the size of the "pg_log" file I have on my mail server database.

 

I have a box with RH7.1 for the mail server and a PG database for the mail users and a memory resident program which keeps on polling with the help of the database.  This keeps on increasing the size of the pg_log (which goes till probably the disk will be full) after which I suppose I will be in a total soup.

 

I tried deleting it once (obviously after taking backup) but then the system could not access the database and I had to restore the original.

 

Please all help will be welcomed before the system goes down.  Currently the size of the "pg_log" is approx. 300MB.  So it is pretty urgent.

 

Thanks in advance

 

-Uday