How to set 'timing on' permanently in PostgreSQL?
\timing is specific to the client psql, not to the database server. You need to put that into the configuration file for psql which is ~/.psqlrc

See the manual for details: https://www.postgresql.org/docs/current/static/app-psql.html#AEN100589


  psql attempts to read and execute commands from the system-wide startup file (psqlrc) and then the user's personal startup file (~/.psqlrc), after connecting to the database but before accepting normal commands