We are having a really interesting problem with our Postgres 9.3 instance in our infrastructure.
Few days ago our box started to show huge CPU spikes while the IO Wait is negligible on the box. After a while I have installed perf and started to monitor the Postgres master process and here is what I have found:
It seems that the box is using __strcoll a lot. The query performance is down, while previously the box was able to sustain with ~20 clients right now it is hardly able to keep up with 5.