Gatsby 4 introduces a significant optimization in its build process through parallel query running, resulting in a 40% reduction in build times for some sites. This improvement addresses a common bottleneck identified in the Gatsby build process, which involves running queries after sourcing site content. The rearchitected data layer now allows page and static queries to occur in parallel, enhancing performance for both developers and site visitors. Historically, Gatsby's data store, based on Redux, was limited to single-thread access, but the new architecture employs lmdb-store for efficient cross-CPU query execution. This change enables the main process to coordinate multiple content query workers, optimizing the build process by leveraging available CPU resources. To benefit from these enhancements, users can update to Gatsby 4 and access detailed documentation for implementation guidance.