Thoth is a real-time Solr monitoring system developed at Trulia to understand search infrastructure without accessing logs. It collects Solr request data, indexes it in another Solr core for search and analysis, and provides a dashboard and APIs for monitoring metrics. It also uses machine learning to predict query times and identify query patterns through topic modeling. The system was designed to be modular and its components like data collection, indexing, dashboard and monitoring are open-sourced.