Before and after upgrade to Percona 5.6

Last week we had a production server that wasn't doing so well on MySQL Oracle Community 5.5. Upgraded it to MySQL Percona 5.6 with the thread pool enabled. Here is the before and after looking at threads:

BEFORE:

AFTER:

Huge difference eh? The after graph has looked the same with no spikes in threads_running or slow queries for three days now. CPU has also lowered a lot. We did double the number of connections allowed from 1200 to 2400. The next day we never got close to that but RAM usage did increase.

The server only had 32 GB of RAM before and after the upgrade. Even though the server was doing much better with Percona Server 5.6, memory started to swap. Doubled it to 64 GB.

Here is CPU before and after: