In Rails 7, the Marginalia gem has been replaced by a native feature that adds comments to queries, making it easier to track down slow queries and improve performance. The new format is sqlcommenter#, which is machine-readable and more valuable in logging and performance monitoring tools. A gem for Rails 7 enables this feature, allowing developers to add comments to queries using the sqlcommenter# format. This gem also introduces a new method called annotate, which lets developers add specific comments to queries. The combination of Rails + sqlcommenter# + PlanetScale Query Insights can greatly improve query debugging experience and is recommended for Rails applications. PlanetScale's built-in query debugging and analysis tool is compatible with the sqlcommenter# format, allowing developers to quickly find and fix issues in their application.