Hi guys,
>>FWIW you still haven't explained how the upgrade was performed. That might be a very important piece of information,
becausethe 9.4 cluster might have hint bits set and/or the data may be mostly frozen, but the
>>9.6 cluster may not have that yet, resulting in higher CPU usage.
We upgraded the database with a pg_dumpall from 8.4.22 and then a psql < BACKUP.SAV command!
Thank you again!
Francesco