Not a lot of people remember what Postgres was like before version 8.4. In many ways, this was the first “modern” release of the database engine. CTEs, Window Functions, column level permissions, in-place upgrade compatible with subsequent versions, collation support, continuous query statistic collection; it was just a smorgasbord of functionality.
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?
With the release of PostgreSQL 8.4, the community gained the ability to use CTE syntax. As such, this is a fairly old feature, yet it’s still misunderstood in a lot of ways. At the same time, the query planner has been advancing incrementally since that time. Most recently, PostgreSQL has gained the ability to perform index-only scans, making it possible to fetch results straight from the index, without confirming rows with the table data.