Fast Search Using PostgreSQL Trigram Text Indexes

What this post added

This post details the implementation of PostgreSQL trigram indexes to improve search performance in GitLab. It explains how trigram indexes work by breaking text into 3-letter sequences and how they can be used with LIKE/ILIKE conditions. The post also covers the technical challenges of integrating this feature while maintaining MySQL compatibility, including modifications to `db/schema.rb` and the introduction of `postgresql_opclasses_support.rb` and `mysql_ignore_postgresql_options.rb` initializers. It also notes the switch to ILIKE on PostgreSQL for better performance.