Bitcoin Core Update Trims Transaction Index Database by 40 GB

A major update has been merged into Bitcoin Core's master branch that could significantly reduce the size of an optional transaction index database. The change, which affects nodes that use the -txindex option, was tested by one contributor and resulted in a reduction from around 66 GB to 26 GB.

This represents a roughly 61% reduction in the size of the database, but operators will need to rebuild their index to capture the full savings. The change is designed to make it easier for nodes to store and retrieve transactions by their full transaction ID.

The redesign stores a shorter lookup key, which is then verified against the full transaction ID to prevent collisions. Lookups are still performed in under 0.2 milliseconds, and the mainnet rebuild took around an hour and 19 minutes in the contributor's test.