Merge bitcoin/bitcoin#19521: Coinstats Index

5f96d7d22d8e05876c6fc014e70488699950fe38 rpc: gettxoutsetinfo rejects hash_serialized_2 for specific height (Fabian Jahr)
23fe50436be641d7417152adc683192649ba206a test: Add test for coinstatsindex behavior in reorgs (Fabian Jahr)
90c966b0f3cfbd6bce5883f46d8527c6853a86a2 rpc: Allow gettxoutsetinfo and getblockstats for stale blocks (Fabian Jahr)
b9362392aef2689bc106c20925859ede555d082b index, rpc: Add use_index option for gettxoutsetinfo (Fabian Jahr)
bb7788b121a30489bc81a1f46dde6a9b19ae4ec1 test: Test coinstatsindex robustness across restarts (Fabian Jahr)
e0938c29099635150014ffc9bb0cafa8049ec55a test: Add tests for block_info in gettxoutsetinfo (Fabian Jahr)
2501576eccb08af80471c7b7b843b189ad6758c0 rpc, index: Add verbose amounts tracking to Coinstats index (Fabian Jahr)
655d929836a71af23d2035d2e2e99ad8b8c340c3 test: add coinstatsindex getindexinfo coverage, improve current tests (Jon Atack)
ca01bb8d689f93e1c7669b0ba7a4994c0206dabd rpc: Add Coinstats index to getindexinfo (Fabian Jahr)
57a026c30fef3138bb8db46e6865acb9dc2674f8 test: Add unit test for Coinstats index (Fabian Jahr)
6a4c0c09ab4d073a26c3c4a02783d5dcd88f6eef test: Add functional test for Coinstats index (Fabian Jahr)
3f166ecc125fce6ccd995687fa16572090a5d099 rpc: gettxoutsetinfo can be requested for specific blockheights (Fabian Jahr)
3c914d58ff323255b32e717d0ce28209ec0abdaa index: Coinstats index can be activated with command line flag (Fabian Jahr)
dd58a4de21469d6d848ae309edc47f558628221d index: Add Coinstats index (Fabian Jahr)
a8a46c4b3cfda4b95c92a36f8cebd3606377e57d refactor: Simplify ApplyStats and ApplyHash (Fabian Jahr)
9c8a265fd21a87228c18a1661df99fedc1866baf refactor: Pass hash_type to CoinsStats in stats object (Fabian Jahr)
2e2648a9021dfbb6e17dfa81472f057dacbc34e0 crypto: Make MuHash Remove method efficient (Fabian Jahr)

Pull request description:

  This is part of the coinstats index project tracked in #18000

  While the review of the new UTXO set hash algorithm (MuHash) takes longer recently #19328 was merged which added the possibility to run `gettxoutsetinfo` with a specific hash type. As the first type it added `hash_type=none` which skips the hashing of the UTXO set altogether. This alone did not make `gettxoutsetinfo` much faster but it allows the use of an index for the remaining coin statistics even before a new hashing algorithm has been added. Credit to Sjors for the idea to take this intermediate step.

  Features summary:
  - Users can start their node with the option `-coinstatsindex` which syncs the index in the background
  - After the index is synced the user can  use `gettxoutsetinfo` with `hash_type=none` or `hash_type=muhash` and will get the response instantly out of the index
  - The user can specify a height or block hash when calling `gettxoutsetinfo` to see coin statistics at a specific block height

ACKs for top commit:
  Sjors:
    re-tACK 5f96d7d22d8e05876c6fc014e70488699950fe38
  jonatack:
    Code review re-ACK 5f96d7d22d8e05876c6fc014e70488699950fe38 per `git range-diff 13d27b4 07201d3 5f96d7d`
  promag:
    Tested ACK 5f96d7d22d8e05876c6fc014e70488699950fe38. Light code review ACK 5f96d7d22d8e05876c6fc014e70488699950fe38.

Tree-SHA512: cbca78bee8e9605c19da4fbcd184625fb280200718396c694a56c7daab6f44ad23ca9fb5456d09f245d8b8d9659fdc2b3f3ce5e953c1c6cf4003dbc74c0463c2

1 files changed, 1 insertions, 0 deletions

diff --git a/src/validation.h b/src/validation.h
index ed1ba4310c..63a8bdc096 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -79,6 +79,7 @@ static const int DEFAULT_SCRIPTCHECK_THREADS = 0;
 static const int64_t DEFAULT_MAX_TIP_AGE = 24 * 60 * 60;
 static const bool DEFAULT_CHECKPOINTS_ENABLED = true;
 static const bool DEFAULT_TXINDEX = false;
+static constexpr bool DEFAULT_COINSTATSINDEX{false};
 static const char* const DEFAULT_BLOCKFILTERINDEX = "0";
 /** Default for -persistmempool */
 static const bool DEFAULT_PERSIST_MEMPOOL = true;