Multimap

cuprate_database does not currently have an abstraction for multimap tables.

All tables are single maps of keys to values.

This matters as this means some of cuprate_blockchain's tables differ from monerod's tables - the primary key is stored for all entries, compared to monerod only needing to store it once:

#![allow(unused)]
fn main() {
// `monerod` only stores `amount: 1` once,
// `cuprated` stores it each time it appears.
struct PreRctOutputId { amount: 1, amount_index: 0 }
struct PreRctOutputId { amount: 1, amount_index: 1 }
}

This means cuprated's database will be slightly larger than monerod's.

The current method cuprate_blockchain uses will be "good enough" as the multimap keys needed for now are fixed, e.g. pre-RCT outputs are no longer being produced.

This may need to change in the future when multimap is all but required, e.g. for FCMP++.

Until then, multimap tables are not implemented as they are tricky to implement across all backends.