* Rename `block_by_height` to `block_header_by_height` in fin state
* Rename `tx_by_hash` to `tx_loc_by_hash` in both (non & fin) states
* Rename `utxo_by_outpoint` to `utxo_by_out_loc` in finalized state
* Reorder the column families so that they match the docs
* Update `struct Chain` in the RFCs
* Increment `DATABASE_FORMAT_VERSION` to 25
* Remove obsolete docs from `0004-asynchronous-script-verification.md`
* Remove an obsolete `TODO` from `disk_db.rs`
* Delete unused snapshots
Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
* Modify UTXO and state designs for transparent coinbase output checks
* Add missing word
* Clarify unspent transparent transaction outputs
And add a definition for OutPoint
* Fix coinbase flag derivation
* Rename SpendPools to SpendRestriction
* Replace coinbase_height with Coinbase.height
And clarify a height to spend_height
* Make block height italic to match spec formatting
* Provide a value for MIN_TRANSPARENT_COINBASE_MATURITY
* Add new v1-4 transaction ID consensus rule
* Make the design match the existing Utxo code
This minimises the changes we'll need to make.
* Add a justification for parallel coinbase verification
* Change to Response::SpendableUtxo
To avoid confusion.
* Update the state RFC to match the current design
* Move a change to another PR to avoid conflicts
* Fix spacing
* Clarify the future returned by `PendingUtxos::queue(u)`
* Add missing PendingUtxos::queue arguments
## Motivation
Prior to this PR we've been using `sled` as our database for storing persistent chain data on the disk between boots. We picked sled over rocksdb to minimize our c++ dependencies despite it being a less mature codebase. The theory was if it worked well enough we'd prefer to have a pure rust codebase, but if we ever ran into problems we knew we could easily swap it out with rocksdb.
Well, we ran into problems. Sled's memory usage was particularly high, and it seemed to be leaking memory. On top of all that, the performance for writes was pretty poor, causing us to become bottle-necked on sled instead of the network.
## Solution
This PR replaces `sled` with `rocksdb`. We've seen a 10x improvement in memory usage out of the box, no more leaking, and much better write performance. With this change writing chain data to disk is no longer a limiting factor in how quickly we can sync the chain.
The code in this pull request has:
- [x] Documentation Comments
- [x] Unit Tests and Property Tests
## Review
@hdevalence
* Begin work on RFC5 implementation
* I think this is necessary
* holy shit supertrait implemented via subtrait
* implement most of the chain functions
* change to slightly better name
* implement fork
* fix outpoint handling in Chain struct
* update expect for work
* resolve review comment
* split utxo into two sets
* update the Chain definition
* just a little more
* update comment
* Apply suggestions from code review
Co-authored-by: teor <teor@riseup.net>
* apply changes from code review
* remove allow attribute in zebra-state/lib.rs
* Update zebra-state/src/memory_state.rs
Co-authored-by: teor <teor@riseup.net>
* merge ChainSet type into MemoryState
* rename state impl types
* Add error messages to asserts
* add module doc comment
* update RFC for utxos
* add missing header
Co-authored-by: teor <teor@riseup.net>
Marek
Dimitris Apostolou
teor
Jane Lusby
Henry de Valence