Prometheus version 2.17 introduced an important update by adding isolation to its time series database (TSDB), addressing a key issue with concurrent queries and data scrapes that could previously result in inconsistent and unexpected data outputs, particularly affecting histogram functions. Isolation, part of the ACID principles critical for database transaction integrity, had been missing in Prometheus, leading to potential discrepancies in queries such as histogram_quantile when samples from different scrapes were involved. The implementation of isolation was initially proposed by Prometheus team member Brian Brazil and later picked up by Goutham Veeramachaneni before being finalized by Björn Rabenstein. Although the addition of isolation slightly increases CPU and memory usage, as well as query latency, these changes are generally negligible under normal circumstances. While the release of Prometheus 2.17 initially raised concerns due to performance issues, these were unrelated to the isolation feature and were quickly addressed in version 2.17.1. This update ensures that queries now produce more reliable results, marking a significant improvement in the Prometheus query process.