Add utxo_by_transparent_addr_loc index to the finalized state

[teor2345]

Motivation

We want to answer transparent address RPCs quickly, so we need new indexes in the finalized state.

Designs

utxo_by_transparent_addr_loc stores unspent transparent output locations by address. UTXO locations are appended by each block.

This list includes the AddressLocation, if it has not been spent.

When a block write deletes a UTXO from utxo_by_out_loc, that UTXO location should be deleted from utxo_by_transparent_addr_loc. The OutputLocations are in order, so the deleted UTXO can be removed efficiently. This is an index optimisation, which does not affect query results. It also simplifies the lookup code.

Types

AddressLocation: the first OutputLocation used by a transparent::Address. Always has the same value for each address, even if the first output is spent.

https://github.com/ZcashFoundation/zebra/blob/main/book/src/dev/rfcs/0005-state-updates.md#rocksdb-data-structures

Tasks

Implementation:

• Add the new column family to the finalized state
• When a block write deletes a UTXO, also delete it from the column family
• Query the finalized index in the ReadRequest for ReadState, if it has already been implemented in:
  • getaddressutxos JSON-RPC method #3158
• Increment the database version

Testing:

• Update raw data snapshot tests
• Add struct data snapshot tests

CI:

• If you added new Rust module files, make sure the paths in the regenerate state job are up to date