Bitcoin Core Upgrade Trims Transaction Index by 40 GB
A major upgrade to Bitcoin's optional transaction index has reduced its size by approximately 40 GB in one contributor's test, from about 66 GB to 26 GB. The redesign, which was merged into Bitcoin Core's master branch on August 15, uses a more compact format that stores only a five-byte prefix and six-byte suffix with full-ID verification to avoid collisions.
The new format, which is intended to improve Bitcoin node storage and performance, requires manual recreation of the index for operators using -txindex. This process reduces rebuild time from 1 hour and 50 minutes to 1 hour and 19 minutes while lookups remain near 0.2 milliseconds.
While the savings are substantial within its narrow scope, capturing them requires planned recreation of the database, plus another rebuild if a rollback becomes necessary. The code is now upstream, but stable binaries follow a separate release process, and migration notes will be available for the release that ships it.