How We Made Our MMDB Files a Third Smaller Without Changing a Byte of Data
Summary
IPinfo explains how they reduced MMDB file sizes by about 31% across 89 databases using hash-consing to share identical subtrees in the MMDB search tree. The optimization preserves the data section and maintains API compatibility, with significant reductions demonstrated (e.g., ipinfo_privacy shrinking from 789 MB to 155 MB). The effort is open source under Apache 2.0, with mmdbshrink available as a standalone tool and mmdbctl updates released to production.