Merge bitcoin/bitcoin#27469: wallet: improve IBD sync time by skipping block scanning prior birth time

82bb7831fa6052620998c7eef47e48ed594248a8 wallet: skip block scan if block was created before wallet birthday (furszy)
a082434d122754ec1a10e0e08a35bdb1f47989e6 refactor: single method to append new spkm to the wallet (furszy)

Pull request description:

  During initial block download, the node's wallet(s) scans every arriving block looking for data that it owns.
  This process can be resource-intensive, as it involves sequentially scanning all transactions within each
  arriving block.

  To avoid wasting processing power, we can skip blocks that occurred before the wallet's creation time,
  since these blocks are guaranteed not to contain any relevant wallet data.

  This has direct implications (an speed improvement) on the underlying blockchain synchronization process
  as well. The reason is that the validation interface queue is limited to 10 tasks per time. This means that no
  more than 10 blocks can be waiting for the wallet(s) to be processed while we are synchronizing the chain
  (activating the best chain to be more precise).
  Which can be a bottleneck if blocks arrive and are processed faster from the network than what they are
  processed by the wallet(s).

  So, by skipping not relevant blocks in the wallet's IBD scanning process, we will also improve the chain
  synchronization time.

ACKs for top commit:
  ishaanam:
    re-ACK 82bb7831fa6052620998c7eef47e48ed594248a8
  achow101:
    re-ACK 82bb7831fa6052620998c7eef47e48ed594248a8
  pinheadmz:
    ACK 82bb7831fa6052620998c7eef47e48ed594248a8

Tree-SHA512: 70158c9657f1fcc396badad2c4410b7b7f439466142640b31a9b1a8cea4555e45ea254e48043c9b27f783d5e4d24d91855f0d79d42f0484b8aa83cdbf3d6c50b

7 files changed, 68 insertions, 12 deletions

diff --git a/src/bench/wallet_balance.cpp b/src/bench/wallet_balance.cpp
index 2c77b9b22b..6cf71f4b83 100644
--- a/src/bench/wallet_balance.cpp
+++ b/src/bench/wallet_balance.cpp
@@ -4,6 +4,7 @@
 
 #include <bench/bench.h>
 #include <interfaces/chain.h>
+#include <node/chainstate.h>
 #include <node/context.h>
 #include <test/util/mining.h>
 #include <test/util/setup_common.h>
@@ -28,6 +29,9 @@ static void WalletBalance(benchmark::Bench& bench, const bool set_dirty, const b
 
     const auto& ADDRESS_WATCHONLY = ADDRESS_BCRT1_UNSPENDABLE;
 
+    // Set clock to genesis block, so the descriptors/keys creation time don't interfere with the blocks scanning process.
+    // The reason is 'generatetoaddress', which creates a chain with deterministic timestamps in the past.
+    SetMockTime(test_setup->m_node.chainman->GetParams().GenesisBlock().nTime);
     CWallet wallet{test_setup->m_node.chain.get(), "", CreateMockableWalletDatabase()};
     {
         LOCK(wallet.cs_wallet);
diff --git a/src/interfaces/chain.h b/src/interfaces/chain.h
index a3fa753a98..40bf0b680c 100644
--- a/src/interfaces/chain.h
+++ b/src/interfaces/chain.h
@@ -87,6 +87,9 @@ struct BlockInfo {
     unsigned data_pos = 0;
     const CBlock* data = nullptr;
     const CBlockUndo* undo_data = nullptr;
+    // The maximum time in the chain up to and including this block.
+    // A timestamp that can only move forward.
+    unsigned int chain_time_max{0};
 
     BlockInfo(const uint256& hash LIFETIMEBOUND) : hash(hash) {}
 };
diff --git a/src/kernel/chain.cpp b/src/kernel/chain.cpp
index 82e77125d7..1c877866d0 100644
--- a/src/kernel/chain.cpp
+++ b/src/kernel/chain.cpp
@@ -16,6 +16,7 @@ interfaces::BlockInfo MakeBlockInfo(const CBlockIndex* index, const CBlock* data
     if (index) {
         info.prev_hash = index->pprev ? index->pprev->phashBlock : nullptr;
         info.height = index->nHeight;
+        info.chain_time_max = index->GetBlockTimeMax();
         LOCK(::cs_main);
         info.file_number = index->nFile;
         info.data_pos = index->nDataPos;
diff --git a/src/wallet/scriptpubkeyman.cpp b/src/wallet/scriptpubkeyman.cpp
index 953fdb63b6..1c8d65c583 100644
--- a/src/wallet/scriptpubkeyman.cpp
+++ b/src/wallet/scriptpubkeyman.cpp
@@ -710,6 +710,8 @@ void LegacyScriptPubKeyMan::UpdateTimeFirstKey(int64_t nCreateTime)
     } else if (!nTimeFirstKey || nCreateTime < nTimeFirstKey) {
         nTimeFirstKey = nCreateTime;
     }
+
+    NotifyFirstKeyTimeChanged(this, nTimeFirstKey);
 }
 
 bool LegacyScriptPubKeyMan::LoadKey(const CKey& key, const CPubKey &pubkey)
@@ -2736,6 +2738,8 @@ void DescriptorScriptPubKeyMan::UpdateWalletDescriptor(WalletDescriptor& descrip
     m_map_script_pub_keys.clear();
     m_max_cached_index = -1;
     m_wallet_descriptor = descriptor;
+
+    NotifyFirstKeyTimeChanged(this, m_wallet_descriptor.creation_time);
 }
 
 bool DescriptorScriptPubKeyMan::CanUpdateToWalletDescriptor(const WalletDescriptor& descriptor, std::string& error)
diff --git a/src/wallet/scriptpubkeyman.h b/src/wallet/scriptpubkeyman.h
index 22b67c88e9..5c7240823f 100644
--- a/src/wallet/scriptpubkeyman.h
+++ b/src/wallet/scriptpubkeyman.h
@@ -256,6 +256,9 @@ public:
 
     /** Keypool has new keys */
     boost::signals2::signal<void ()> NotifyCanGetAddressesChanged;
+
+    /** Birth time changed */
+    boost::signals2::signal<void (const ScriptPubKeyMan* spkm, int64_t new_birth_time)> NotifyFirstKeyTimeChanged;
 };
 
 /** OutputTypes supported by the LegacyScriptPubKeyMan */
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index b3eed8abc7..d5268afbf6 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -1436,6 +1436,12 @@ void CWallet::blockConnected(const interfaces::BlockInfo& block)
 
     m_last_block_processed_height = block.height;
     m_last_block_processed = block.hash;
+
+    // No need to scan block if it was created before the wallet birthday.
+    // Uses chain max time and twice the grace period to adjust time for block time variability.
+    if (block.chain_time_max < m_birth_time.load() - (TIMESTAMP_WINDOW * 2)) return;
+
+    // Scan block
     for (size_t index = 0; index < block.data->vtx.size(); index++) {
         SyncTransaction(block.data->vtx[index], TxStateConfirmed{block.hash, block.height, static_cast<int>(index)});
         transactionRemovedFromMempool(block.data->vtx[index], MemPoolRemovalReason::BLOCK);
@@ -1779,6 +1785,14 @@ bool CWallet::ImportScriptPubKeys(const std::string& label, const std::set<CScri
     return true;
 }
 
+void CWallet::FirstKeyTimeChanged(const ScriptPubKeyMan* spkm, int64_t new_birth_time)
+{
+    int64_t birthtime = m_birth_time.load();
+    if (new_birth_time < birthtime) {
+        m_birth_time = new_birth_time;
+    }
+}
+
 /**
  * Scan active chain for relevant transactions after importing keys. This should
  * be called whenever new keys are added to the wallet, with the oldest key
@@ -3107,6 +3121,14 @@ std::shared_ptr<CWallet> CWallet::Create(WalletContext& context, const std::stri
     // Try to top up keypool. No-op if the wallet is locked.
     walletInstance->TopUpKeyPool();
 
+    // Cache the first key time
+    std::optional<int64_t> time_first_key;
+    for (auto spk_man : walletInstance->GetAllScriptPubKeyMans()) {
+        int64_t time = spk_man->GetTimeFirstKey();
+        if (!time_first_key || time < *time_first_key) time_first_key = time;
+    }
+    if (time_first_key) walletInstance->m_birth_time = *time_first_key;
+
     if (chain && !AttachChain(walletInstance, *chain, rescan_required, error, warnings)) {
         return nullptr;
     }
@@ -3182,11 +3204,7 @@ bool CWallet::AttachChain(const std::shared_ptr<CWallet>& walletInstance, interf
     {
         // No need to read and scan block if block was created before
         // our wallet birthday (as adjusted for block time variability)
-        std::optional<int64_t> time_first_key;
-        for (auto spk_man : walletInstance->GetAllScriptPubKeyMans()) {
-            int64_t time = spk_man->GetTimeFirstKey();
-            if (!time_first_key || time < *time_first_key) time_first_key = time;
-        }
+        std::optional<int64_t> time_first_key = walletInstance->m_birth_time.load();
         if (time_first_key) {
             FoundBlock found = FoundBlock().height(rescan_height);
             chain.findFirstBlockWithTimeAndHeight(*time_first_key - TIMESTAMP_WINDOW, rescan_height, found);
@@ -3498,6 +3516,14 @@ LegacyScriptPubKeyMan* CWallet::GetOrCreateLegacyScriptPubKeyMan()
     return GetLegacyScriptPubKeyMan();
 }
 
+void CWallet::AddScriptPubKeyMan(const uint256& id, std::unique_ptr<ScriptPubKeyMan> spkm_man)
+{
+    const auto& spkm = m_spk_managers[id] = std::move(spkm_man);
+
+    // Update birth time if needed
+    FirstKeyTimeChanged(spkm.get(), spkm->GetTimeFirstKey());
+}
+
 void CWallet::SetupLegacyScriptPubKeyMan()
 {
     if (!m_internal_spk_managers.empty() || !m_external_spk_managers.empty() || !m_spk_managers.empty() || IsWalletFlagSet(WALLET_FLAG_DESCRIPTORS)) {
@@ -3509,7 +3535,8 @@ void CWallet::SetupLegacyScriptPubKeyMan()
         m_internal_spk_managers[type] = spk_manager.get();
         m_external_spk_managers[type] = spk_manager.get();
     }
-    m_spk_managers[spk_manager->GetID()] = std::move(spk_manager);
+    uint256 id = spk_manager->GetID();
+    AddScriptPubKeyMan(id, std::move(spk_manager));
 }
 
 const CKeyingMaterial& CWallet::GetEncryptionKey() const
@@ -3527,6 +3554,7 @@ void CWallet::ConnectScriptPubKeyManNotifiers()
     for (const auto& spk_man : GetActiveScriptPubKeyMans()) {
         spk_man->NotifyWatchonlyChanged.connect(NotifyWatchonlyChanged);
         spk_man->NotifyCanGetAddressesChanged.connect(NotifyCanGetAddressesChanged);
+        spk_man->NotifyFirstKeyTimeChanged.connect(std::bind(&CWallet::FirstKeyTimeChanged, this, std::placeholders::_1, std::placeholders::_2));
     }
 }
 
@@ -3534,10 +3562,10 @@ void CWallet::LoadDescriptorScriptPubKeyMan(uint256 id, WalletDescriptor& desc)
 {
     if (IsWalletFlagSet(WALLET_FLAG_EXTERNAL_SIGNER)) {
         auto spk_manager = std::unique_ptr<ScriptPubKeyMan>(new ExternalSignerScriptPubKeyMan(*this, desc, m_keypool_size));
-        m_spk_managers[id] = std::move(spk_manager);
+        AddScriptPubKeyMan(id, std::move(spk_manager));
     } else {
         auto spk_manager = std::unique_ptr<ScriptPubKeyMan>(new DescriptorScriptPubKeyMan(*this, desc, m_keypool_size));
-        m_spk_managers[id] = std::move(spk_manager);
+        AddScriptPubKeyMan(id, std::move(spk_manager));
     }
 }
 
@@ -3558,7 +3586,7 @@ void CWallet::SetupDescriptorScriptPubKeyMans(const CExtKey& master_key)
             }
             spk_manager->SetupDescriptorGeneration(master_key, t, internal);
             uint256 id = spk_manager->GetID();
-            m_spk_managers[id] = std::move(spk_manager);
+            AddScriptPubKeyMan(id, std::move(spk_manager));
             AddActiveScriptPubKeyMan(id, t, internal);
         }
     }
@@ -3606,7 +3634,7 @@ void CWallet::SetupDescriptorScriptPubKeyMans()
                 auto spk_manager = std::unique_ptr<ExternalSignerScriptPubKeyMan>(new ExternalSignerScriptPubKeyMan(*this, m_keypool_size));
                 spk_manager->SetupDescriptor(std::move(desc));
                 uint256 id = spk_manager->GetID();
-                m_spk_managers[id] = std::move(spk_manager);
+                AddScriptPubKeyMan(id, std::move(spk_manager));
                 AddActiveScriptPubKeyMan(id, t, internal);
             }
         }
@@ -3723,7 +3751,8 @@ ScriptPubKeyMan* CWallet::AddWalletDescriptor(WalletDescriptor& desc, const Flat
         spk_man = new_spk_man.get();
 
         // Save the descriptor to memory
-        m_spk_managers[new_spk_man->GetID()] = std::move(new_spk_man);
+        uint256 id = new_spk_man->GetID();
+        AddScriptPubKeyMan(id, std::move(new_spk_man));
     }
 
     // Add the private keys to the descriptor
@@ -3866,7 +3895,8 @@ bool CWallet::ApplyMigrationData(MigrationData& data, bilingual_str& error)
             error = _("Error: Duplicate descriptors created during migration. Your wallet may be corrupted.");
             return false;
         }
-        m_spk_managers[desc_spkm->GetID()] = std::move(desc_spkm);
+        uint256 id = desc_spkm->GetID();
+        AddScriptPubKeyMan(id, std::move(desc_spkm));
     }
 
     // Remove the LegacyScriptPubKeyMan from disk
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 79f4c43456..e74eeb0a99 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -299,6 +299,10 @@ private:
     // Local time that the tip block was received. Used to schedule wallet rebroadcasts.
     std::atomic<int64_t> m_best_block_time {0};
 
+    // First created key time. Used to skip blocks prior to this time.
+    // 'std::numeric_limits<int64_t>::max()' if wallet is blank.
+    std::atomic<int64_t> m_birth_time{std::numeric_limits<int64_t>::max()};
+
     /**
      * Used to keep track of spent outpoints, and
      * detect and report conflicts (double-spends or
@@ -380,6 +384,10 @@ private:
     // ScriptPubKeyMan::GetID. In many cases it will be the hash of an internal structure
     std::map<uint256, std::unique_ptr<ScriptPubKeyMan>> m_spk_managers;
 
+    // Appends spk managers into the main 'm_spk_managers'.
+    // Must be the only method adding data to it.
+    void AddScriptPubKeyMan(const uint256& id, std::unique_ptr<ScriptPubKeyMan> spkm_man);
+
     /**
      * Catch wallet up to current chain, scanning new blocks, updating the best
      * block locator and m_last_block_processed, and registering for
@@ -641,6 +649,9 @@ public:
     bool ImportPubKeys(const std::vector<CKeyID>& ordered_pubkeys, const std::map<CKeyID, CPubKey>& pubkey_map, const std::map<CKeyID, std::pair<CPubKey, KeyOriginInfo>>& key_origins, const bool add_keypool, const bool internal, const int64_t timestamp) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     bool ImportScriptPubKeys(const std::string& label, const std::set<CScript>& script_pub_keys, const bool have_solving_data, const bool apply_label, const int64_t timestamp) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
+    /** Updates wallet birth time if 'new_birth_time' is below it */
+    void FirstKeyTimeChanged(const ScriptPubKeyMan* spkm, int64_t new_birth_time);
+
     CFeeRate m_pay_tx_fee{DEFAULT_PAY_TX_FEE};
     unsigned int m_confirm_target{DEFAULT_TX_CONFIRM_TARGET};
     /** Allow Coin Selection to pick unconfirmed UTXOs that were sent from our own wallet if it