There are a lot of languages available for authoring Postgres functions, but there’s nothing quite like the the classic PL/pgSQL. It’s SQL! It’s not SQL! It’s a kind of horrifying mutant crossbreed suitable only for terrifying small children and generating complex reports from a cavalcade of dubious sources! And deep within its twisted entrails is an often overlooked feature usually only available in far more mature entities.
That’s right, it’s obvious we’re referring to the ASSERT statement.
The United States held an election recently, and there has been some … mild controversy regarding the results. Many raised issues about this before the election itself, but what if we had used instant-runoff voting instead? More importantly, can we implement it with Postgres?
Well, the answer to the last question is a strong affirmative. So long as we don’t break the results down into voting districts, and make wild unsupported assumptions regarding rankings, that is.
Say hi to Princess Kittybutt. She’ll be our mascot (and subject) for today. We’ll get to her in a minute.
When the only tool you have is a hammer, everything becomes a nail, right? With Postgres becoming more of an environment than simply a database engine, this colloquialism is starting to resemble reality. Of course, that’s not necessarily a bad thing! As Postgres accumulates copious and varied extensions, its role as an adaptive middleware solidifies.
It’s no surprise Postgres does more than merely store data; you can’t do everything with SQL. Often, it’s often more beneficial to process data locally without transmitting it to a client interface. Local manipulation can save hours in network traffic alone, let alone client-side allocation and per-row processing. Databases like Postgres are specifically for bulk data operations, so why not take advantage?
But doing that requires functions—anonymous or otherwise—and a Turing-complete language to write them with.
Back in 2005, I started a new job with a company that did work for other businesses. Their data model was designed by developers and they had no DBA, as is pretty common in smaller organizations. A critical part of our main application relied on an event log that captured customer activity and relayed their final decision to the client for reconciliation. One day someone noticed that there was a bug in the system that resolved the final decision from the event stack, and panic ensued.