Does "vpmovzxbd" Scare You? Here's Why it Doesn't Have To

QuestDB is an open-source time-series database designed for high-performance workloads, offering ultra-low latency, high ingestion throughput, and leveraging a multi-tier storage engine with native support for Parquet and SQL to ensure data portability and readiness for AI applications. The database employs a Just-In-Time (JIT) compiler for SQL queries, utilizing hand-coded Single Instruction, Multiple Data (SIMD) instructions to optimize performance by processing multiple data points in parallel. The article delves into the intricacies of SIMD instructions, explaining their structure and evolution, and how they are used to enhance database operations by placing data of the same type close together, allowing for efficient parallel processing. It also introduces the AsmJit library, which facilitates the JIT compilation process by simplifying the emission of Intel instructions, and provides examples of how SIMD instructions can be applied to optimize SQL operations like null checking in VARCHAR and BINARY columns. The author shares personal insights and challenges faced when learning SIMD, emphasizing the importance of understanding the architecture and instruction sets, and concludes by reflecting on the niche appeal of handcoding SIMD despite its limited demand in the job market.