Software performance matters… is a slightly unpopular view these days. There are plenty of reasons why you might care about performance. If you’re an engineer, you might care intrinsically about the beauty of your code: that craftsmanlike quality which permeates every line you write, it’s often tied to how fast your code will run. Most people, though, will care about performance insofar as it’s instrumental to their commercial goals, like serving users or winning market share.
One of the biggest open problems in databases is materialised views. Imagine you are repeatedly querying a database after any change. The result of your queries is the materialised view. This view must update as new data streams in. You shouldn’t have to pay the cost of a full query each time. The database should be clever enough to compute a minimal incremental change from the current state of your view. It seems reasonable, yet it’s too much to ask of current databases.