ClickHouse Release 26.3

ClickHouse version 26.3 introduces numerous enhancements, including 27 new features, 40 performance optimizations, and 202 bug fixes, with significant contributions from a growing community of developers. This release enables asynchronous inserts by default, substantially improving throughput by batching data on the server side rather than relying on client-side operations. The MATERIALIZED clause for Common Table Expressions (CTEs) now optimizes query performance by evaluating subqueries once and storing results in temporary tables, while the naturalSortKey function enhances sorting capabilities for more intuitive data organization. Additionally, JOIN reordering has been extended to support more join types, such as ANTI, SEMI, and FULL, improving execution efficiency across complex join scenarios. Enhancements to the Map data type's storage format reduce data processing time by implementing hash-based bucketing, which accelerates single-key lookups. New settings for the EXPLAIN clause, such as pretty=1 for indented output and compact=1 for collapsing expression steps, help users better understand query execution plans. These improvements collectively aim to boost ClickHouse's performance, efficiency, and user experience, particularly in handling large datasets and complex queries.