Doubling the Sorting Speed of Postgres Network Types with Abbreviated Keys

A deep dive into a PostgreSQL patch that adds SortSupport abbreviated keys for the inet and cidr network types, more than doubling their sorting speed. The post explains how inet/cidr values are structured (family, netmask bits, subnet bits), the non-obvious sort semantics (network bits compared first, then netmask size, then subnet), and how an abbreviated key is designed to pack sorting-relevant information into a pointer-sized datum. On 64-bit machines with IPv4, all four sort criteria fit into the key, enabling nearly full sort resolution without heap lookups. The implementation uses bitmasking, byte-swapping for endianness, and bitwise OR assembly. The patch benefits all Postgres installations sorting or indexing on network types.