pg_stat_statements not found even with "shared_preload_libraries = 'pg_stat_statements'

I have followed the instructions given below:

http://www.postgresql.org/docs/9.3/static/pgstatstatements.html

... to the effect of adding the following lines:

# postgresql.conf
shared_preload_libraries = 'pg_stat_statements'
pg_stat_statements.max = 10000
pg_stat_statements.track = all

In file postgresql.conf and then restarting the server but the table pg_stat_statements is still not visible:

$ cat /usr/share/postgresql/9.3/postgresql.conf | grep -A3 ^shared_preload_libraries
shared_preload_libraries = 'pg_stat_statements' # (change requires restart)
pg_stat_statements.max = 10000
pg_stat_statements.track = all

$ sudo /etc/init.d/postgresql restart
* Restarting PostgreSQL 9.3 database server          [ OK ] 

$ psql -U postgres
psql (9.3.10)
Type "help" for help.

postgres=# select count(*) from pg_stat_activity;
count 
-------
      1
(1 row)

postgres=# select count(*) from pg_stat_statements;
ERROR:  relation "pg_stat_statements" does not exist

update

After executing:

sudo apt-get install postgresql-contrib-9.3

And then doing:

$ psql -U postgres
psql (9.4.5, server 9.3.10)
Type "help" for help.

postgres=# create extension pg_stat_statements;
CREATE EXTENSION
postgres=# \dx
                                     List of installed extensions
         Name        | Version |   Schema   |                        Description                        
--------------------+---------+------------+-----------------------------------------------------------
 pg_stat_statements | 1.1     | public     | track execution statistics of all SQL statements executed
 plpgsql            | 1.0     | pg_catalog | PL/pgSQL procedural language
 (2 rows)

 postgres=# \quit
$ sudo /etc/init.d/postgresql restart
 * Restarting PostgreSQL 9.3 database server  [OK]

... I now get:

postgres=# select * from pg_stat_statements ;
ERROR:  pg_stat_statements must be loaded via shared_preload_libraries

system details

I am running on `Ubuntu 14.

Recent versions of Postgres install conf files in different locations than they used to be in. There is sometimes a template .conf file that exists (but is not actually used), and then also an active .conf file (in a completely different location). I discovered this by scouring through the /etc/init.d files. It's possible that the .conf file you edited is not actually the one that is being used by the database.

You can find the location of the conf file used by your database by connecting to the database and querying SHOW config_file

Here is a link to your follow up question (in case anyone in the future finds it useful)

StackExchange Database Administrators Q#124054, answer score: 6