sql_trace

Ever wondered where do those SQL calls come from in your Rails app?

sql_trace allows to trace code that makes ActiveRecord SQL queries that appear in development server's log. It also allows to filter them in order to trace heavy ones or ones with matching SQL.

This makes it very useful during app-db optimizations.

Add to Gemfile:

gem 'sql_trace', group: :development

Then run:

bundle install

Start development server like this:

SQL_TRACE=1 rails server

This way you'll get 5-line traces for all SQL queries. You can customize that using options described below.

You can write options when invoking Rails server or store them in .env file and use dotenv or foreman gems to load them.

Following options are available:

Changes the stack size to N (must be at least 2, defaults to 5).

Uses colorize gem to make traces look distinct within server log. The gem must be installed separately.

Only prints traces for queries that take at least specified duration. Duration is in ms.

Only prints traces for queries whose SQL match given string or /regex/