Hannu has been working with PostgreSQL since it was called Postgres95 (and also played around with Postgres 4.2 - without the "SQL" - a little before that)
Hannu was the first DBA at Skype, where he wrote patches for making VACUUM able to work on more than one table in parallel and invented the sharding and remote call language pl/proxy to enable using PostgreSQL in infinitely scalable way and also participated in design of other 24/7 enterprise features.
After Skype he did 10+ years of PostgreSQL consulting all over the world as part of 2ndQuadrant.
Currently works as a Database Engineer at Google