On MySQL side, or should I say MariaDB one :
- Google swaps out MySQL, moves to MariaDB : beyond the significative reference for MariaDB and the fact that Google will sustain his effort to patch MariaDB as they did for MySQL, the question that raised for me was : how long will Percona go with MySQL ? Percona's server was seen as an advanced version of MySQL with the inclusion of some patches (like Google's one for performance, etc) and for the tools they provide with/aside (like Percona toolkit or Xtrabackup). It does not seem they plan to make the switch so far...
- Scaling your database via InnoDB table compression : where you can eliminate slow queries via innodb table compression. Constraints and limits are explained in the post.
On Postgres side :
- As planned, Postgres 9.3 was released on 9th september :
Testing new Postgresql versions without messing up your existing install : as you could guess, article describes on how to compile postgres so that you can have several versions on your server, without impacting your production instance.
4 tips for working with dates in Postgresql : an introduction to what you can do with dates in Postgres.
If you are more a beginner in Postgres world, you may be interested by Postgresql basics by example, which is more about how to connect, how to create a user, etc.
If you come from MySQL world, you may want to know what are the postgres equivalents of "show databases", "show tables", "show columns", "describe table".
You want to strengthen the traffic between your app servers and your postgres ones, you may want to use SSL encryption and certificates.
If you are a NoSQL addict, you can consider Postgres as a good solution for your next project as you can store and validate schemaless content and that you can use either the JSON or Hstore module of Postgres (PDF) for this.
More generally and even if it's a postgres example which is used, you should use UUIDs for your keys instead of traditionnal keys. Beyond unicity, if you are to use distributed systems, it would be one (or the only ?) way to avoid conflicts.