The storage engine of Prometheus 2.x, known as TSDB, has undergone significant advancements over the past year, highlighted at PromCon 2019 by Ganesh Vernekar. Initially developed independently, TSDB has now been integrated into the Prometheus repository and has seen contributions from over 60 developers. Key developments include the resolution of overlapping TSDB blocks that enabled backfilling, the use of Google's Snappy algorithm for WAL compression reducing WAL size by up to 50%, and various optimizations that have improved query execution time and reduced memory usage. Enhancements also include a new TSDB CLI command for analyzing data churn and cardinality, and the introduction of a read-only mode. Future plans involve implementing isolation in TSDB to achieve full ACID compliance, lifting index size limits to accommodate larger data sets, and improving WAL checkpointing to enhance performance and reduce memory usage. These innovations aim to make Prometheus more efficient and scalable, with ongoing community contributions playing a crucial role in its development.