The blog post by George Utsin discusses the vectorization of the merge join operator in CockroachDB, a SQL database designed for global business applications. The traditional merge join algorithm, which efficiently processes sorted data, often underperforms due to the overhead of its integration into a database system. To address this, the vectorized approach processes data a column at a time, reducing the need for repeated type checks and conversions, thereby boosting efficiency. CockroachDB's vectorized merge join operator incorporates probing and building phases to handle data one column at a time, optimizing performance and supporting various join types and data types. The vectorized merge joiner has demonstrated a significant performance improvement, offering up to a 20x increase in speed for certain queries compared to the traditional row-by-row approach. This development moves CockroachDB closer to a production-ready vectorized execution engine, freeing up CPU resources for other queries.