Christmas gifts from the ClickHouse engineering team

At the end of each year, the ClickHouse engineering team introduces new features as "Christmas gifts," which include usability improvements and long-awaited updates. Some notable developments highlighted in the blog post include the ability to highlight digit groups in query prompts for better readability, and the enhancement of numeric hints for large numbers in query results. Additionally, the optimization of the distinctJSONPaths function in ClickHouse 25.12 significantly improves performance by utilizing pre-existing metadata, resulting in processing times that are over 50 times faster compared to previous versions. Similarly, DISTINCT queries on LowCardinality columns are now optimized to leverage dictionary encoding, providing faster query execution except in cases where unique values are dispersed. Furthermore, the optimization of SEMI JOIN queries through filter pushdown in ClickHouse 25.12 allows for more efficient data processing by reducing the amount of data scanned and read from disk, achieving approximately 30% faster query execution and data read reduction.