You could store it in a hash and flush it to disk using something like https://en.wikipedia.org/wiki/Cdb_(software) https://en.wikipedia.org/wiki/Cdb_(software)

You could store it in a hash and flush it to disk using something like https://en.wikipedia.org/wiki/Cdb_(software) https://en.wikipedia.org/wiki/Cdb_(software), there are a few variants and implementations that might do what you want.