ClickHouse Release 24.4

ClickHouse, a free and open-source columnar DBMS (Database Management System), has released version 24.4 with several new features and improvements. These include support for the QUALIFY clause in SQL queries, better performance for specific JOIN use cases, and more efficient memory usage during query execution. The QUALIFY clause allows users to filter data based on window functions without needing to introduce a Common Table Expression (CTE). This can make certain types of queries simpler and easier to understand. In terms of join performance improvements, there are two main changes in 24.4. The first is better predicate pushdown, which means that the analyzer works out when a filter condition can be applied to both sides of a JOIN. This can lead to significant speedups for certain types of queries. The second improvement involves automatically converting an OUTER JOIN to an INNER JOIN if the predicate after the JOIN filters out any non-joined rows. This can also result in faster query execution times. Overall, these enhancements aim to make ClickHouse even more powerful and efficient for handling large datasets and complex queries.