PostgreSQL is an all round impressive Relational DataBase Management System which implements the SQL standard (see the very useful reference page Comparison of different SQL implementations for details). PostgreSQL also provides with unique solutions in the database market and has been leading innovation for some years now. Still, there’s no support for Autonomous Transactions within the server itself. Let’s have a look at how to easily implement them with PL/Proxy.
In our previous article about Loading Geolocation Data, we did load some data into PostgreSQL and saw the quite noticable impact of a user transformation. As it happens, the function that did the integer to IP representation was so naive as to scratch the micro optimisation itch of some Common Lisp hackers: thanks a lot guys, in particular stassats who came up with the solution we’re seeing now.
In our ongoing Tour of Extensions we played with earth distance in How far is the nearest pub? then with hstore in a series about trigger, first to generalize Trigger Parameters then to enable us to Auditing Changes with Hstore. Today we are going to work with pg_trgm which is the trigrams PostgreSQL extension: its usage got seriously enhanced in recent PostgreSQL releases and it’s now a poor’s man Full Text Search engine.
In a previous article about Trigger Parameters we have been using the extension hstore in order to compute some extra field in our records, where the fields used both for the computation and for storing the results were passed in as dynamic parameters. Today we’re going to see another trigger use case for hstore: we are going to record changes made to our tuples.