The Left-Prefix Index Rule
02/05/19 There’s an important heuristic in database indexing that I call the left-prefix rule. It helps you understand whether the database will be able to make the best use of a m…
02/05/19 There’s an important heuristic in database indexing that I call the left-prefix rule. It helps you understand whether the database will be able to make the best use of a m…
02/01/19 A covering index is a fantastic query performance optimization. An index covers a query when the index has all the data needed to execute the query, so the server can retr…
01/30/19 Databases have a kind of iron triangle for specific types of query plans, whereby they can pick between two out of three things but can’t get all three of them. (The “iron…
01/28/19 Databases are confusing! Not only are they complicated bits of software, but database jargon is really complicated. Part of this comes from the number of words with multip…
01/23/19 What’s an ORM? If you’re not familiar with ORMs, an ORM is an Object-Relational Mapper, which helps you map objects in your code to tables in your database, without writin…
09/12/18 If you use ACID transactional databases, you’ve probably heard of lock wait timeouts and deadlocks. What are these? And how are they different? Inevitably, many of us will…
07/30/18 I wrote a couple of “definitions and nuances” posts about terminology in databases recently (cardinality, selectivity), and today I want to write one about cardinality in …
07/18/18 I wrote recently about database cardinality, and there’s a closely related topic that is equally confusing and I want to explain too: index selectivity. Index selectivity …
04/26/18 You have to be careful what you wish for. The signal:noise ratio of finding out which indexes are “unused” is low. This isn’t obvious at first glance, but upon deeper insp…
01/04/18 It’s easy to observe (pun intended) in the rear-view mirror. Hindsight bias aside, 2017 was a big year for SolarWinds Database Performance Monitor (DPM) and our customers!…
12/03/17 Monitoring is a hopelessly overloaded term in tech culture. The term now carries decades of inaccurate and imprecise use. The result is that several people can be engaged …
11/07/17 I’ve written before about the minimal set of metrics that can serve effectively as application/service vital signs. One such set is the RED acronym, which stands for Reque…