ClickHouse Release 26.5

The ClickHouse 26.5 release introduces a range of enhancements, including 38 new features, 51 performance optimizations, and 224 bug fixes. Notably, this release optimizes the ORDER BY ... LIMIT pushdown through joins, offering up to a 20× speed increase and significantly reduced memory usage. It also introduces a GROUP BY ... LIMIT shortcut, a filesystem table function to run SQL against local file systems, and extends Top-N optimizations to GROUP BY queries. The release welcomes new contributors and highlights the growing community that supports ClickHouse's popularity. Additional features include the url_base setting for easier URL management, a negative LIMIT BY for selecting rows from the end of groups, and multi-path SQL/JSON capabilities. An experimental in-browser ClickHouse client is also introduced, and query caching can now be controlled on a per-subquery basis. These updates aim to enhance query performance, flexibility, and usability in ClickHouse, making it easier to manage and analyze large datasets.