What is the proper way to separate queries from other messages while logging?
For example:
I have 'log_min_duration_statement' parameter in postgresql.conf . Therefore I get postgresql system messages and slow queries in one log file /var/log/postgresql/postgresql-9.3-main.log .
In order to simplify further reading I'd like to get slow queries in /var/log/postgresql/postgresql-slowqueries.log and all the rest in /var/log/postgresql/postgresql.log.
I tried to implement this by means of rsyslog but didn't manage to get any decent result.
AFAIK, there is no such mechanism which would help you log different types of messages to separate logfiles.
If you like to separate messages in the logfile - you need to either have an offline process (like perl or shell script) which would help you identify and separate the types of messages logged and generate two different logfiles.
In a much simpler way - if your only concern is to log slow queries, then reporting tools like pgbadger or pg_query_analyzer or pgsi would help you do so.