Using Datadog APM to improve the performance of Homebrew

As a Software Engineering Intern at Datadog, the author contributed to open source projects using Application Performance Monitoring (APM) tools to identify performance bottlenecks and compare different implementations. They initially worked on optimizing Homebrew, a package management system for macOS extensively used by Datadog's engineering teams. The author identified the slowest part of the 'brew linkage' command and implemented caching using SQLite3, which significantly improved performance. They also tried pstore and DBM as alternative caching mechanisms but found SQLite3 to be faster. Their optimizations met the requirements specification by processing over 50 packages in under 5 seconds. The author recommended proceeding with the DBM implementation due to its benefits such as not requiring a third-party gem, cleaner code structure, and Ruby's native Hash get/set conventions.