I'm using postgresql 9.4 and here's extension details.
List of installed extensions
Name | Version | Schema | Description
--------------------+---------+------------+-----------------------------------------------------------
btree_gist | 1.0 | public | support for indexing common datatypes in GiST
pg_qualstats | 0.0.4 | public | An extension collecting statistics about quals
pg_stat_kcache | 2.0.2 | public | Kernel cache statistics gathering
pg_stat_statements | 1.2 | public | track execution statistics of all SQL statements executed
plpgsql | 1.0 | pg_catalog | PL/pgSQL procedural language
powa | 2.0 | public | PostgreSQL Workload Analyser-core
I'm using postgresql 9.4 and here's extension details.
postgresql.conf
The query details are empty and powaqualstats* tables are empty too.