Access Path Selection in a Relational Database Management System - Notes Through Chapter 3

Fri, 10 Apr 2026 00:00:00 +0000

This post is a study dump. I’ve been reading Access Path Selection in a Relational Database Management System (Selinger et al., 1979) and stopped at chapter 3 to consolidate what I learned. I used available internet resource and tools to go deeper on the examples and make the concepts more concrete.

What the paper covers

The paper describes how System R, an experimental relational database built at IBM in the 1970s, chooses access paths to execute SQL queries. You write SQL declaratively, without specifying how data is accessed or in what order joins happen. The optimizer decides both, minimizing total access cost.

What fork() actually copies and how it impact your celery service

Sat, 28 Mar 2026 00:00:00 +0000

Shallow changes can have consequences at the bottom of the ocean. This post is an account of something that happened to me recently, and the story is still open. The services are stable, the revert held, and a pull request is sitting there waiting for the team to review. The proposed solution makes sense on paper. Whether it fully solves the problem in practice is something we’ll only know after thorough testing in staging next week.

Postgresql on Daniel's Tech Blog

Access Path Selection in a Relational Database Management System - Notes Through Chapter 3

What the paper covers

What fork() actually copies and how it impact your celery service