Activate pg_stat_statements on PostgreSQL

gistfile1.txt

1) Edit file postgresql.conf and add the next 3 lines (any where):

shared_preload_libraries = 'pg_stat_statements'
pg_stat_statements.max = 10000
pg_stat_statements.track = all

2) Restart PostgreSQL

3) Execute the next command on psql, pgAdmin or similar:

CREATE EXTENSION pg_stat_statements;

4) Checking some results:

SELECT query, calls, total_time, rows, 100.0 * shared_blks_hit / nullif(shared_blks_hit + shared_blks_read, 0) AS hit_percent FROM pg_stat_statements ORDER BY total_time DESC LIMIT 5;

SELECT 
  (total_time / 1000 / 60) as total_minutes, 
  (total_time/calls) as average_time, 
  query 
FROM pg_stat_statements 
ORDER BY 1 DESC 
LIMIT 100;

5) More information:
http://www.postgresql.org/docs/9.4/static/pgstatstatements.html