Amir Sheffer, a Product Manager, discusses the complexities of data querying as groundcover develops a migration tool from legacy vendors to its platform. The effort involved revisiting their querying framework to handle every edge case and translate queries from other observability vendors into groundcover's languages. Utilizing ClickHouse for logs, traces, and events, and VictoriaMetrics for metrics, they settled on MetricsQL for metrics querying due to its power and expressiveness. They introduced a MetricsQL query builder that seamlessly switches between builder and code modes to enhance user experience. For logs, traces, and events, they created a middleware query language inspired by Victoria's LogsQL to optimize both simple and complex queries, ensuring the entire platform speaks the same language. The development process involved extensive optimization and deep-dive sessions, resulting in a robust framework that serves 95% of use cases while providing flexibility for the remaining 5%. As they continue to expand the framework's reach into areas like RUM session analytics and security use cases, they acknowledge that data querying remains an unsolved problem, but believe they have crafted a strong solution.