* Changed: We have migrated to Postgresql 9.3 (from 9.1), giving us the speed benefits of the latest version.
* Optimised: We have turned off Postgresql's synchronous_commit (but left fsync on), which means the database isn't trying to write to the database on disk at the end of every single transaction. With this we get a massive speed boost. The trade off is the fact we could lose a tiny fraction of data from current transactions if there is a server crash (somewhere between 200ms and 1 second worth of transactions at most). Postgresql's Write Ahead Logs and the Battery Backup Unit on our disk controller make even this loss unlikely.
* Optimised: GreenReaper did some fantastic work tuning our Postgresql database settings to get the query planner to be way more efficient. This has eliminated a long running issue where users might occasionally get slow or failed searches, especially if they have a lot of blocked keywords.
* Optimised: GreenReaper and starling did lots of database refactoring and optimisation including dropping superfluous columns and unused indexes, using more appropriate data types in places, etc. These changes have given us more speed and a smaller database. Read more about that here!
* Optimised: We have implemented a bunch of filesystem tuning tricks to get the maximum speed out of our SATA storage disk array and the SSDs where the Database lives.
* Fixed: Backslash character no longer breaks some searches if it appears at the start of a search string.
* Fixed: Various other minor bugs and security issues have been squashed.