Migrate to most recent PostgreSQL version
It is EOL for PostgreSQL 9.2 next year and we had a lot of issues with locking and high CPU load on database. It is time to upgrade. Also, migrating from 9.2 to 9.4/9.5 will give 10%-20% increase in performance.
Additional links:
https://www.postgresql.org/support/versioning/
https://wiki.postgresql.org/wiki/What's_new_in_PostgreSQL_9.5#Lock_scalability_improvements - could it be our case???
https://wiki.postgresql.org/wiki/What's_new_in_PostgreSQL_9.3#Replication_Improvements