Create log file only for my executed queries
The log_statement in postgresql.conf applies to all users and all databases, but if it's not what you want, you may provide per-database and per-user values, with:

ALTER USER someuser SET log_statement='all';


and/or

ALTER DATABASE dbname SET log_statement='all';


and leave log_statement to 'none' in the global configuration file postgresql.conf.

Also when you're superuser, you can enable logging anytime just for your session with:

SET log_statement='all';


As to what is logged, it can be configured with log_line_prefix but it doesn't go as far as logging tables and columns names. To log which columns are affected by UPDATEs you'd need to do that in triggers in every table, as in tablelog