[ part 1 | part 2 | part 3 ] In the previous article I explained that the main requirement for high-speed in-memory data scanning is column-oriented storage format for in-memory data. SIMD instruction processing is just icing on the cake. Let’s dig deeper. This is a long post, you’ve been warned. Test Environment I will cover full test results in the next article in this series. First, let’s look into the test setup, environment and what tools I used for peeking inside CPU hardware. I...| tanelpoder.com
Here’s a list of reasons why SELECT * is bad for SQL performance, assuming that your application doesn’t actually need all the columns. When I write production code, I explicitly specify the columns of interest in the select-list (projection), not only for performance reasons, but also for application reliability reasons. For example, will your application’s data processing code suddenly break when a new column has been added or the column order has changed in a table? - Linux, Oracle, ...| tanelpoder.com