edbed31066 chainparams: add signet assumeutxo param at height 160_000 (Sjors Provoost)
b8cafe3871 chainparams: add testnet assumeutxo param at height 2_500_000 (Sjors Provoost)
99839bbfa7 doc: add note about confusing HaveTxsDownloaded name (James O'Beirne)
7ee46a755f contrib: add script to demo/test assumeutxo (James O'Beirne)
42cae39356 test: add feature_assumeutxo functional test (James O'Beirne)
0f64bac603 rpc: add getchainstates (James O'Beirne)
bb05857794 refuse to activate a UTXO snapshot if mempool not empty (James O'Beirne)
ce585a9a15 rpc: add loadtxoutset (James O'Beirne)
62ac519e71 validation: do not activate snapshot if behind active chain (James O'Beirne)
9511fb3616 validation: assumeutxo: swap m_mempool on snapshot activation (James O'Beirne)
7fcd21544a blockstorage: segment normal/assumedvalid blockfiles (James O'Beirne)
4c3b8ca35c validation: populate nChainTx value for assumedvalid chainstates (James O'Beirne)
49ef778158 test: adjust chainstate tests to use recognized snapshot base (James O'Beirne)
1019c39982 validation: pruning for multiple chainstates (James O'Beirne)
373cf91531 validation: indexing changes for assumeutxo (James O'Beirne)
1fffdd76a1 net_processing: validationinterface: ignore some events for bg chain (James O'Beirne)
fbe0a7d7ca wallet: validationinterface: only handle active chain notifications (James O'Beirne)
f073917a9e validationinterface: only send zmq notifications for active (James O'Beirne)
4d8f4dcb45 validation: pass ChainstateRole for validationinterface calls (James O'Beirne)
1e59acdf17 validation: only call UpdatedBlockTip for active chainstate (James O'Beirne)
c6af23c517 validation: add ChainstateRole (James O'Beirne)
9f2318c76c validation: MaybeRebalanceCaches when chain leaves IBD (James O'Beirne)
434495a8c1 chainparams: add blockhash to AssumeutxoData (James O'Beirne)
c711ca186f assumeutxo: remove snapshot during -reindex{-chainstate} (James O'Beirne)
c93ef43e4f bugfix: correct is_snapshot_cs in VerifyDB (James O'Beirne)
b73d3bbd23 net_processing: Request assumeutxo background chain blocks (Suhas Daftuar)
Pull request description:
- Background and FAQ: https://github.com/jamesob/assumeutxo-docs/tree/2019-04-proposal/proposal
- Prior progress/project: https://github.com/bitcoin/bitcoin/projects/11
- Replaces https://github.com/bitcoin/bitcoin/pull/15606, which was closed due to Github slowness. Original description and commentary can be found there.
---
This changeset finishes the first phase of the assumeutxo project. It makes UTXO snapshots loadable via RPC (`loadtxoutset`) and adds `assumeutxo` parameters to chainparams. It contains all the remaining changes necessary to both use an assumedvalid snapshot chainstate and do a full validation sync in the background.
This may look like a lot to review, but note that
- ~200 lines are a (non-essential) demo shell script
- Many lines are functional test, documentation, and relatively dilute RPC code.
So it shouldn't be as burdensome to review as the linecount might suggest.
- **P2P**: minor changes are made to `init.cpp` and `net_processing.cpp` to make simultaneous IBD across multiple chainstates work.
- **Pruning**: implement correct pruning behavior when using a background chainstate
- **Blockfile separation**: to prevent "fragmentation" in blockfile storage, have background chainstates use separate blockfiles from active snapshot chainstates to avoid interleaving heights and impairing pruning.
- **Indexing**: some `CValidationInterface` events are given with an additional parameter, ChainstateRole, and all indexers ignore events from ChainstateRole::ASSUMEDVALID so that indexation only happens sequentially.
- Have `-reindex` properly wipe snapshot chainstates.
- **RPC**: introduce RPC commands `loadtxoutset` and (hidden) `getchainstates`.
- **Release docs & first assumeutxo commitment**: add notes and a particular assumeutxo hash value for first AU-enabled release.
- This will complete the project and allow use of UTXO snapshots for faster node bootstrap.
The next phase, if it were to be pursued, would be coming up with a way to distribute the UTXO snapshots over the P2P network.
---
### UTXO snapshots
Create your own with `./contrib/devtools/utxo_snapshot.sh`, e.g.
```shell
./contrib/devtools/utxo_snapshot.sh 788000 utxo.dat ./src/bitcoin-cli -datadir=$(pwd)/testdata`)
```
or use the pre-generated ones listed below.
- Testnet: **2'500'000** (Sjors):
- torrent: `magnet:?xt=urn:btih:511e09f4bf853aefab00de5c070b1e031f0ecbe9&dn=utxo-testnet-2500000.dat&tr=udp%3A%2F%2Ftracker.bitcoin.sprovoost.nl%3A6969`
- sha256: `79db4b025448cc0ac388d8589a28eab02de53055d181e34eb47391717aa16388`
- Signet: **160'000** (Sjors):
- torrent: `magnet:?xt=urn:btih:9da986cb27b3980ea7fd06b21e199b148d486880&dn=utxo-signet-160000.dat&tr=udp%3A%2F%2Ftracker.bitcoin.sprovoost.nl%3A6969`
- sha256: `eeeca845385ba91e84ef58c09d38f98f246a24feadaad57fe1e5874f3f92ef8c`
- Mainnet: **800'000** (Sjors):
- Note: this needs the following commit cherry-picked in: 24deb2022b
- torrent: `magnet:?xt=urn:btih:50ee955bef37f5ec3e5b0df4cf0288af3d715a2e&dn=utxo-800000.dat&tr=udp%3A%2F%2Ftracker.bitcoin.sprovoost.nl%3A6969`
### Testing
#### For fun (~5min)
If you want to do a quick test, you can run `./contrib/devtools/test_utxo_snapshots.sh` and follow the instructions. This is mostly obviated by the functional tests, though.
#### For real (longer)
If you'd like to experience a real usage of assumeutxo, you can do that too.
I've cut a new snapshot at height 788'000 (http://img.jameso.be/utxo-788000.dat - but you can do it yourself with `./contrib/devtools/utxo_snapshot.sh` if you want). Download that, and then create a datadir for testing:
```sh
$ cd ~/src/bitcoin # or whatever
# get the snapshot
$ curl http://img.jameso.be/utxo-788000.dat > utxo-788000.dat
# you'll want to do this if you like copy/pasting
$ export AU_DATADIR=/home/${USER}/au-test # or wherever
$ mkdir ${AU_DATADIR}
$ vim ${AU_DATADIR}/bitcoin.conf
dbcache=8000 # or, you know, something high
blockfilterindex=1
coinstatsindex=1
prune=3000
logthreadnames=1
```
Obtain this branch, build it, and then start bitcoind:
```sh
$ git remote add jamesob https://github.com/jamesob/bitcoin
$ git fetch jamesob assumeutxo
$ git checkout jamesob/assumeutxo
$ ./configure $conf_args && make # (whatever you like to do here)
# start 'er up and watch the logs
$ ./src/bitcoind -datadir=${AU_DATADIR}
```
Then, in some other window, load the snapshot
```sh
$ ./src/bitcoin-cli -datadir=${AU_DATADIR} loadtxoutset $(pwd)/utxo-788000.dat
```
You'll see some log messages about headers retrieval and waiting to see the snapshot in the headers chain. Once you get the full headers chain, you'll spend a decent amount of time (~10min) loading the snapshot, checking it, and flushing it to disk. After all that happens, you should be syncing to tip in pretty short order, and you'll see the occasional `[background validation]` log message go by.
In yet another window, you can check out chainstate status with
```sh
$ ./src/bitcoin-cli -datadir=${AU_DATADIR} getchainstates
```
as well as usual favorites like `getblockchaininfo`.
ACKs for top commit:
achow101:
ACK edbed31066
Tree-SHA512: 6086fb9a38dc7df85fedc76b30084dd8154617a2a91e89a84fb41326d34ef8e7d7ea593107afba01369093bf8cc91770621d98f0ea42a5b3b99db868d2f14dc2
and remove m_snapshot_validated. This state can now be inferred by the
number of isUsable chainstates.
m_disabled is used to signal that a chainstate should no longer be used
by validation logic; it is used as a sentinel when background validation
completes or if the snapshot chainstate is found to be invalid.
isUsable is a convenience method that incorporates m_disabled.
