>"There are numerous use cases for stashing metadata into those unused bits. Memory allocators could use that space to track different memory pools, for example

>"There are numerous use cases for stashing metadata into those unused bits. Memory allocators could use that space to track different memory pools, for example, or for garbage collection. Database management systems have their own uses for that space." Can someone say which databases do this and what they're making use of those unused bits in the address for?