Merge bitcoin/bitcoin#27224: refactor: Remove CAddressBookData::destdata

a5986e82dd2b8f923d60f9e31760ef62b9010105 refactor: Remove CAddressBookData::destdata (Ryan Ofsky)
5938ad0bdb013953861c7cd15a95f00998a06f44 wallet: Add DatabaseBatch::ErasePrefix method (Ryan Ofsky)

Pull request description:

  This is cleanup that doesn't change external behavior. Benefits of the cleanup are:

  - Removes awkward `StringMap` intermediate representation for wallet address metadata.
  - Simplifies `CWallet`, deals with used address and received request serialization in `walletdb.cpp` instead of higher level wallet code
  - Adds test coverage and documentation

  This PR doesn't change externally observable behavior. Internally, the only change in behavior is that `EraseDestData` deletes rows directly from the database because they are no longer stored in memory. This is more direct and efficient because it uses a single lookup and scan instead of multiple lookups.

  Motivation for this cleanup is making changes like #18550, #18192, #13756 easier to reason about and less likely to result in unintended behavior and bugs

  ---

  This PR is a rebased copy of #18608. For some reason that PR is locked and couldn't be reopened or commented on.

  This PR is an alternative to #27215 with differences described in https://github.com/bitcoin/bitcoin/pull/27215#pullrequestreview-1329028143

ACKs for top commit:
  achow101:
    ACK a5986e82dd2b8f923d60f9e31760ef62b9010105
  furszy:
    Code ACK a5986e82

Tree-SHA512: 6bd3e402f1f60263fbd433760bdc29d04175ddaf8307207c4a67d59f6cffa732e176ba57886e02926f7a1615dce0ed9cda36c8cbc6430aa8e5b56934c23f3fe7

11 files changed, 215 insertions, 95 deletions

diff --git a/src/wallet/bdb.cpp b/src/wallet/bdb.cpp
index 4eab342495..fa6e56c6e4 100644
--- a/src/wallet/bdb.cpp
+++ b/src/wallet/bdb.cpp
@@ -668,12 +668,14 @@ void BerkeleyDatabase::ReloadDbEnv()
     env->ReloadDbEnv();
 }
 
-BerkeleyCursor::BerkeleyCursor(BerkeleyDatabase& database)
+BerkeleyCursor::BerkeleyCursor(BerkeleyDatabase& database, BerkeleyBatch* batch)
 {
     if (!database.m_db.get()) {
         throw std::runtime_error(STR_INTERNAL_BUG("BerkeleyDatabase does not exist"));
     }
-    int ret = database.m_db->cursor(nullptr, &m_cursor, 0);
+    // Transaction argument to cursor is only needed when using the cursor to
+    // write to the database. Read-only cursors do not need a txn pointer.
+    int ret = database.m_db->cursor(batch ? batch->txn() : nullptr, &m_cursor, 0);
     if (ret != 0) {
         throw std::runtime_error(STR_INTERNAL_BUG(strprintf("BDB Cursor could not be created. Returned %d", ret)));
     }
@@ -820,6 +822,25 @@ bool BerkeleyBatch::HasKey(DataStream&& key)
     return ret == 0;
 }
 
+bool BerkeleyBatch::ErasePrefix(Span<const std::byte> prefix)
+{
+    if (!TxnBegin()) return false;
+    auto cursor{std::make_unique<BerkeleyCursor>(m_database, this)};
+    // const_cast is safe below even though prefix_key is an in/out parameter,
+    // because we are not using the DB_DBT_USERMEM flag, so BDB will allocate
+    // and return a different output data pointer
+    Dbt prefix_key{const_cast<std::byte*>(prefix.data()), static_cast<uint32_t>(prefix.size())}, prefix_value{};
+    int ret{cursor->dbc()->get(&prefix_key, &prefix_value, DB_SET_RANGE)};
+    for (int flag{DB_CURRENT}; ret == 0; flag = DB_NEXT) {
+        SafeDbt key, value;
+        ret = cursor->dbc()->get(key, value, flag);
+        if (ret != 0 || key.get_size() < prefix.size() || memcmp(key.get_data(), prefix.data(), prefix.size()) != 0) break;
+        ret = cursor->dbc()->del(0);
+    }
+    cursor.reset();
+    return TxnCommit() && (ret == 0 || ret == DB_NOTFOUND);
+}
+
 void BerkeleyDatabase::AddRef()
 {
     LOCK(cs_db);
diff --git a/src/wallet/bdb.h b/src/wallet/bdb.h
index ff24081696..4fac128bf1 100644
--- a/src/wallet/bdb.h
+++ b/src/wallet/bdb.h
@@ -192,10 +192,11 @@ private:
     Dbc* m_cursor;
 
 public:
-    explicit BerkeleyCursor(BerkeleyDatabase& database);
+    explicit BerkeleyCursor(BerkeleyDatabase& database, BerkeleyBatch* batch=nullptr);
     ~BerkeleyCursor() override;
 
     Status Next(DataStream& key, DataStream& value) override;
+    Dbc* dbc() const { return m_cursor; }
 };
 
 /** RAII class that provides access to a Berkeley database */
@@ -206,6 +207,7 @@ private:
     bool WriteKey(DataStream&& key, DataStream&& value, bool overwrite = true) override;
     bool EraseKey(DataStream&& key) override;
     bool HasKey(DataStream&& key) override;
+    bool ErasePrefix(Span<const std::byte> prefix) override;
 
 protected:
     Db* pdb{nullptr};
@@ -230,6 +232,7 @@ public:
     bool TxnBegin() override;
     bool TxnCommit() override;
     bool TxnAbort() override;
+    DbTxn* txn() const { return activeTxn; }
 };
 
 std::string BerkeleyDatabaseVersion();
diff --git a/src/wallet/db.h b/src/wallet/db.h
index 2da94885be..6834ba6963 100644
--- a/src/wallet/db.h
+++ b/src/wallet/db.h
@@ -110,6 +110,7 @@ public:
 
         return HasKey(std::move(ssKey));
     }
+    virtual bool ErasePrefix(Span<const std::byte> prefix) = 0;
 
     virtual std::unique_ptr<DatabaseCursor> GetNewCursor() = 0;
     virtual bool TxnBegin() = 0;
@@ -186,6 +187,7 @@ private:
     bool WriteKey(DataStream&& key, DataStream&& value, bool overwrite = true) override { return true; }
     bool EraseKey(DataStream&& key) override { return true; }
     bool HasKey(DataStream&& key) override { return true; }
+    bool ErasePrefix(Span<const std::byte> prefix) override { return true; }
 
 public:
     void Flush() override {}
diff --git a/src/wallet/interfaces.cpp b/src/wallet/interfaces.cpp
index 1cde4207e2..cd438cfe2f 100644
--- a/src/wallet/interfaces.cpp
+++ b/src/wallet/interfaces.cpp
@@ -228,9 +228,22 @@ public:
         return m_wallet->GetAddressReceiveRequests();
     }
     bool setAddressReceiveRequest(const CTxDestination& dest, const std::string& id, const std::string& value) override {
+        // Note: The setAddressReceiveRequest interface used by the GUI to store
+        // receive requests is a little awkward and could be improved in the
+        // future:
+        //
+        // - The same method is used to save requests and erase them, but
+        //   having separate methods could be clearer and prevent bugs.
+        //
+        // - Request ids are passed as strings even though they are generated as
+        //   integers.
+        //
+        // - Multiple requests can be stored for the same address, but it might
+        //   be better to only allow one request or only keep the current one.
         LOCK(m_wallet->cs_wallet);
         WalletBatch batch{m_wallet->GetDatabase()};
-        return m_wallet->SetAddressReceiveRequest(batch, dest, id, value);
+        return value.empty() ? m_wallet->EraseAddressReceiveRequest(batch, dest, id)
+                             : m_wallet->SetAddressReceiveRequest(batch, dest, id, value);
     }
     bool displayAddress(const CTxDestination& dest) override
     {
diff --git a/src/wallet/sqlite.cpp b/src/wallet/sqlite.cpp
index d6259e095e..77e8a4e9c1 100644
--- a/src/wallet/sqlite.cpp
+++ b/src/wallet/sqlite.cpp
@@ -125,6 +125,7 @@ void SQLiteBatch::SetupSQLStatements()
         {&m_insert_stmt, "INSERT INTO main VALUES(?, ?)"},
         {&m_overwrite_stmt, "INSERT or REPLACE into main values(?, ?)"},
         {&m_delete_stmt, "DELETE FROM main WHERE key = ?"},
+        {&m_delete_prefix_stmt, "DELETE FROM main WHERE instr(key, ?) = 1"},
     };
 
     for (const auto& [stmt_prepared, stmt_text] : statements) {
@@ -375,6 +376,7 @@ void SQLiteBatch::Close()
         {&m_insert_stmt, "insert"},
         {&m_overwrite_stmt, "overwrite"},
         {&m_delete_stmt, "delete"},
+        {&m_delete_prefix_stmt, "delete prefix"},
     };
 
     for (const auto& [stmt_prepared, stmt_description] : statements) {
@@ -441,24 +443,34 @@ bool SQLiteBatch::WriteKey(DataStream&& key, DataStream&& value, bool overwrite)
     return res == SQLITE_DONE;
 }
 
-bool SQLiteBatch::EraseKey(DataStream&& key)
+bool SQLiteBatch::ExecStatement(sqlite3_stmt* stmt, Span<const std::byte> blob)
 {
     if (!m_database.m_db) return false;
-    assert(m_delete_stmt);
+    assert(stmt);
 
     // Bind: leftmost parameter in statement is index 1
-    if (!BindBlobToStatement(m_delete_stmt, 1, key, "key")) return false;
+    if (!BindBlobToStatement(stmt, 1, blob, "key")) return false;
 
     // Execute
-    int res = sqlite3_step(m_delete_stmt);
-    sqlite3_clear_bindings(m_delete_stmt);
-    sqlite3_reset(m_delete_stmt);
+    int res = sqlite3_step(stmt);
+    sqlite3_clear_bindings(stmt);
+    sqlite3_reset(stmt);
     if (res != SQLITE_DONE) {
         LogPrintf("%s: Unable to execute statement: %s\n", __func__, sqlite3_errstr(res));
     }
     return res == SQLITE_DONE;
 }
 
+bool SQLiteBatch::EraseKey(DataStream&& key)
+{
+    return ExecStatement(m_delete_stmt, key);
+}
+
+bool SQLiteBatch::ErasePrefix(Span<const std::byte> prefix)
+{
+    return ExecStatement(m_delete_prefix_stmt, prefix);
+}
+
 bool SQLiteBatch::HasKey(DataStream&& key)
 {
     if (!m_database.m_db) return false;
diff --git a/src/wallet/sqlite.h b/src/wallet/sqlite.h
index 5745a1d4cf..d9de40569b 100644
--- a/src/wallet/sqlite.h
+++ b/src/wallet/sqlite.h
@@ -36,13 +36,16 @@ private:
     sqlite3_stmt* m_insert_stmt{nullptr};
     sqlite3_stmt* m_overwrite_stmt{nullptr};
     sqlite3_stmt* m_delete_stmt{nullptr};
+    sqlite3_stmt* m_delete_prefix_stmt{nullptr};
 
     void SetupSQLStatements();
+    bool ExecStatement(sqlite3_stmt* stmt, Span<const std::byte> blob);
 
     bool ReadKey(DataStream&& key, DataStream& value) override;
     bool WriteKey(DataStream&& key, DataStream&& value, bool overwrite = true) override;
     bool EraseKey(DataStream&& key) override;
     bool HasKey(DataStream&& key) override;
+    bool ErasePrefix(Span<const std::byte> prefix) override;
 
 public:
     explicit SQLiteBatch(SQLiteDatabase& database);
diff --git a/src/wallet/test/wallet_tests.cpp b/src/wallet/test/wallet_tests.cpp
index edcfaa24e5..da4b553394 100644
--- a/src/wallet/test/wallet_tests.cpp
+++ b/src/wallet/test/wallet_tests.cpp
@@ -427,19 +427,63 @@ BOOST_AUTO_TEST_CASE(ComputeTimeSmart)
     BOOST_CHECK_EQUAL(AddTx(*m_node.chainman, m_wallet, 5, 50, 600), 300);
 }
 
-BOOST_AUTO_TEST_CASE(LoadReceiveRequests)
+static const DatabaseFormat DATABASE_FORMATS[] = {
+#ifdef USE_SQLITE
+    DatabaseFormat::SQLITE,
+#endif
+#ifdef USE_BDB
+    DatabaseFormat::BERKELEY,
+#endif
+};
+
+void TestLoadWallet(const std::string& name, DatabaseFormat format, std::function<void(std::shared_ptr<CWallet>)> f)
 {
-    CTxDestination dest = PKHash();
-    LOCK(m_wallet.cs_wallet);
-    WalletBatch batch{m_wallet.GetDatabase()};
-    m_wallet.SetAddressUsed(batch, dest, true);
-    m_wallet.SetAddressReceiveRequest(batch, dest, "0", "val_rr0");
-    m_wallet.SetAddressReceiveRequest(batch, dest, "1", "val_rr1");
-
-    auto values = m_wallet.GetAddressReceiveRequests();
-    BOOST_CHECK_EQUAL(values.size(), 2U);
-    BOOST_CHECK_EQUAL(values[0], "val_rr0");
-    BOOST_CHECK_EQUAL(values[1], "val_rr1");
+    node::NodeContext node;
+    auto chain{interfaces::MakeChain(node)};
+    DatabaseOptions options;
+    options.require_format = format;
+    DatabaseStatus status;
+    bilingual_str error;
+    std::vector<bilingual_str> warnings;
+    auto database{MakeWalletDatabase(name, options, status, error)};
+    auto wallet{std::make_shared<CWallet>(chain.get(), "", std::move(database))};
+    BOOST_CHECK_EQUAL(wallet->LoadWallet(), DBErrors::LOAD_OK);
+    WITH_LOCK(wallet->cs_wallet, f(wallet));
+}
+
+BOOST_FIXTURE_TEST_CASE(LoadReceiveRequests, TestingSetup)
+{
+    for (DatabaseFormat format : DATABASE_FORMATS) {
+        const std::string name{strprintf("receive-requests-%i", format)};
+        TestLoadWallet(name, format, [](std::shared_ptr<CWallet> wallet) EXCLUSIVE_LOCKS_REQUIRED(wallet->cs_wallet) {
+            BOOST_CHECK(!wallet->IsAddressPreviouslySpent(PKHash()));
+            WalletBatch batch{wallet->GetDatabase()};
+            BOOST_CHECK(batch.WriteAddressPreviouslySpent(PKHash(), true));
+            BOOST_CHECK(batch.WriteAddressPreviouslySpent(ScriptHash(), true));
+            BOOST_CHECK(wallet->SetAddressReceiveRequest(batch, PKHash(), "0", "val_rr00"));
+            BOOST_CHECK(wallet->EraseAddressReceiveRequest(batch, PKHash(), "0"));
+            BOOST_CHECK(wallet->SetAddressReceiveRequest(batch, PKHash(), "1", "val_rr10"));
+            BOOST_CHECK(wallet->SetAddressReceiveRequest(batch, PKHash(), "1", "val_rr11"));
+            BOOST_CHECK(wallet->SetAddressReceiveRequest(batch, ScriptHash(), "2", "val_rr20"));
+        });
+        TestLoadWallet(name, format, [](std::shared_ptr<CWallet> wallet) EXCLUSIVE_LOCKS_REQUIRED(wallet->cs_wallet) {
+            BOOST_CHECK(wallet->IsAddressPreviouslySpent(PKHash()));
+            BOOST_CHECK(wallet->IsAddressPreviouslySpent(ScriptHash()));
+            auto requests = wallet->GetAddressReceiveRequests();
+            auto erequests = {"val_rr11", "val_rr20"};
+            BOOST_CHECK_EQUAL_COLLECTIONS(requests.begin(), requests.end(), std::begin(erequests), std::end(erequests));
+            WalletBatch batch{wallet->GetDatabase()};
+            BOOST_CHECK(batch.WriteAddressPreviouslySpent(PKHash(), false));
+            BOOST_CHECK(batch.EraseAddressData(ScriptHash()));
+        });
+        TestLoadWallet(name, format, [](std::shared_ptr<CWallet> wallet) EXCLUSIVE_LOCKS_REQUIRED(wallet->cs_wallet) {
+            BOOST_CHECK(!wallet->IsAddressPreviouslySpent(PKHash()));
+            BOOST_CHECK(!wallet->IsAddressPreviouslySpent(ScriptHash()));
+            auto requests = wallet->GetAddressReceiveRequests();
+            auto erequests = {"val_rr11"};
+            BOOST_CHECK_EQUAL_COLLECTIONS(requests.begin(), requests.end(), std::begin(erequests), std::end(erequests));
+        });
+    }
 }
 
 // Test some watch-only LegacyScriptPubKeyMan methods by the procedure of loading (LoadWatchOnly),
@@ -922,6 +966,7 @@ private:
     bool WriteKey(DataStream&& key, DataStream&& value, bool overwrite = true) override { return m_pass; }
     bool EraseKey(DataStream&& key) override { return m_pass; }
     bool HasKey(DataStream&& key) override { return m_pass; }
+    bool ErasePrefix(Span<const std::byte> prefix) override { return m_pass; }
 
 public:
     explicit FailBatch(bool pass) : m_pass(pass) {}
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 56bd25b90a..caf95a3f03 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -967,11 +967,11 @@ void CWallet::SetSpentKeyState(WalletBatch& batch, const uint256& hash, unsigned
     CTxDestination dst;
     if (ExtractDestination(srctx->tx->vout[n].scriptPubKey, dst)) {
         if (IsMine(dst)) {
-            if (used != IsAddressUsed(dst)) {
+            if (used != IsAddressPreviouslySpent(dst)) {
                 if (used) {
                     tx_destinations.insert(dst);
                 }
-                SetAddressUsed(batch, dst, used);
+                SetAddressPreviouslySpent(batch, dst, used);
             }
         }
     }
@@ -984,7 +984,7 @@ bool CWallet::IsSpentKey(const CScript& scriptPubKey) const
     if (!ExtractDestination(scriptPubKey, dest)) {
         return false;
     }
-    if (IsAddressUsed(dest)) {
+    if (IsAddressPreviouslySpent(dest)) {
         return true;
     }
     if (IsLegacy()) {
@@ -992,15 +992,15 @@ bool CWallet::IsSpentKey(const CScript& scriptPubKey) const
         assert(spk_man != nullptr);
         for (const auto& keyid : GetAffectedKeys(scriptPubKey, *spk_man)) {
             WitnessV0KeyHash wpkh_dest(keyid);
-            if (IsAddressUsed(wpkh_dest)) {
+            if (IsAddressPreviouslySpent(wpkh_dest)) {
                 return true;
             }
             ScriptHash sh_wpkh_dest(GetScriptForDestination(wpkh_dest));
-            if (IsAddressUsed(sh_wpkh_dest)) {
+            if (IsAddressPreviouslySpent(sh_wpkh_dest)) {
                 return true;
             }
             PKHash pkh_dest(keyid);
-            if (IsAddressUsed(pkh_dest)) {
+            if (IsAddressPreviouslySpent(pkh_dest)) {
                 return true;
             }
         }
@@ -2403,19 +2403,15 @@ bool CWallet::DelAddressBook(const CTxDestination& address)
     WalletBatch batch(GetDatabase());
     {
         LOCK(cs_wallet);
-        // If we want to delete receiving addresses, we need to take care that DestData "used" (and possibly newer DestData) gets preserved (and the "deleted" address transformed into a change entry instead of actually being deleted)
-        // NOTE: This isn't a problem for sending addresses because they never have any DestData yet!
-        // When adding new DestData, it should be considered here whether to retain or delete it (or move it?).
+        // If we want to delete receiving addresses, we should avoid calling EraseAddressData because it will delete the previously_spent value. Could instead just erase the label so it becomes a change address, and keep the data.
+        // NOTE: This isn't a problem for sending addresses because they don't have any data that needs to be kept.
+        // When adding new address data, it should be considered here whether to retain or delete it.
         if (IsMine(address)) {
             WalletLogPrintf("%s called with IsMine address, NOT SUPPORTED. Please report this bug! %s\n", __func__, PACKAGE_BUGREPORT);
             return false;
         }
-        // Delete destdata tuples associated with address
-        std::string strAddress = EncodeDestination(address);
-        for (const std::pair<const std::string, std::string> &item : m_address_book[address].destdata)
-        {
-            batch.EraseDestData(strAddress, item.first);
-        }
+        // Delete data rows associated with this address
+        batch.EraseAddressData(address);
         m_address_book.erase(address);
     }
 
@@ -2790,51 +2786,42 @@ unsigned int CWallet::ComputeTimeSmart(const CWalletTx& wtx, bool rescanning_old
     return nTimeSmart;
 }
 
-bool CWallet::SetAddressUsed(WalletBatch& batch, const CTxDestination& dest, bool used)
+bool CWallet::SetAddressPreviouslySpent(WalletBatch& batch, const CTxDestination& dest, bool used)
 {
-    const std::string key{"used"};
     if (std::get_if<CNoDestination>(&dest))
         return false;
 
     if (!used) {
-        if (auto* data = util::FindKey(m_address_book, dest)) data->destdata.erase(key);
-        return batch.EraseDestData(EncodeDestination(dest), key);
+        if (auto* data{util::FindKey(m_address_book, dest)}) data->previously_spent = false;
+        return batch.WriteAddressPreviouslySpent(dest, false);
     }
 
-    const std::string value{"1"};
-    m_address_book[dest].destdata.insert(std::make_pair(key, value));
-    return batch.WriteDestData(EncodeDestination(dest), key, value);
+    LoadAddressPreviouslySpent(dest);
+    return batch.WriteAddressPreviouslySpent(dest, true);
 }
 
-void CWallet::LoadDestData(const CTxDestination &dest, const std::string &key, const std::string &value)
+void CWallet::LoadAddressPreviouslySpent(const CTxDestination& dest)
 {
-    m_address_book[dest].destdata.insert(std::make_pair(key, value));
+    m_address_book[dest].previously_spent = true;
 }
 
-bool CWallet::IsAddressUsed(const CTxDestination& dest) const
+void CWallet::LoadAddressReceiveRequest(const CTxDestination& dest, const std::string& id, const std::string& request)
 {
-    const std::string key{"used"};
-    std::map<CTxDestination, CAddressBookData>::const_iterator i = m_address_book.find(dest);
-    if(i != m_address_book.end())
-    {
-        CAddressBookData::StringMap::const_iterator j = i->second.destdata.find(key);
-        if(j != i->second.destdata.end())
-        {
-            return true;
-        }
-    }
+    m_address_book[dest].receive_requests[id] = request;
+}
+
+bool CWallet::IsAddressPreviouslySpent(const CTxDestination& dest) const
+{
+    if (auto* data{util::FindKey(m_address_book, dest)}) return data->previously_spent;
     return false;
 }
 
 std::vector<std::string> CWallet::GetAddressReceiveRequests() const
 {
-    const std::string prefix{"rr"};
     std::vector<std::string> values;
-    for (const auto& address : m_address_book) {
-        for (const auto& data : address.second.destdata) {
-            if (!data.first.compare(0, prefix.size(), prefix)) {
-                values.emplace_back(data.second);
-            }
+    for (const auto& [dest, entry] : m_address_book) {
+        for (const auto& [id, request] : entry.receive_requests) {
+            values.emplace_back(request);
         }
     }
     return values;
@@ -2842,15 +2829,15 @@ std::vector<std::string> CWallet::GetAddressReceiveRequests() const
 
 bool CWallet::SetAddressReceiveRequest(WalletBatch& batch, const CTxDestination& dest, const std::string& id, const std::string& value)
 {
-    const std::string key{"rr" + id}; // "rr" prefix = "receive request" in destdata
-    CAddressBookData& data = m_address_book.at(dest);
-    if (value.empty()) {
-        if (!batch.EraseDestData(EncodeDestination(dest), key)) return false;
-        data.destdata.erase(key);
-    } else {
-        if (!batch.WriteDestData(EncodeDestination(dest), key, value)) return false;
-        data.destdata[key] = value;
-    }
+    if (!batch.WriteAddressReceiveRequest(dest, id, value)) return false;
+    m_address_book[dest].receive_requests[id] = value;
+    return true;
+}
+
+bool CWallet::EraseAddressReceiveRequest(WalletBatch& batch, const CTxDestination& dest, const std::string& id)
+{
+    if (!batch.EraseAddressReceiveRequest(dest, id)) return false;
+    m_address_book[dest].receive_requests.erase(id);
     return true;
 }
 
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 581a6bd9cb..5252b46cdc 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -221,17 +221,22 @@ struct CAddressBookData
     std::optional<AddressPurpose> purpose;
 
     /**
-     * Additional address metadata map that can currently hold two types of keys:
-     *
-     *   "used" keys with values always set to "1" or "p" if present. This is set on
-     *       IsMine addresses that have already been spent from if the
-     *       avoid_reuse option is enabled
-     *
-     *   "rr##" keys where ## is a decimal number, with serialized
-     *       RecentRequestEntry objects as values
+     * Whether coins with this address have previously been spent. Set when the
+     * the wallet avoid_reuse option is enabled and this is an IsMine address
+     * that has already received funds and spent them. This is used during coin
+     * selection to increase privacy by not creating different transactions
+     * that spend from the same addresses.
+     */
+    bool previously_spent{false};
+
+    /**
+     * Map containing data about previously generated receive requests
+     * requesting funds to be sent to this address. Only present for IsMine
+     * addresses. Map keys are decimal numbers uniquely identifying each
+     * request, and map values are serialized RecentRequestEntry objects
+     * containing BIP21 URI information including message and amount.
      */
-    typedef std::map<std::string, std::string> StringMap;
-    StringMap destdata;
+    std::map<std::string, std::string> receive_requests{};
 
     /** Accessor methods. */
     bool IsChange() const { return !label.has_value(); }
@@ -511,8 +516,10 @@ public:
 
     bool LoadMinVersion(int nVersion) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet) { AssertLockHeld(cs_wallet); nWalletVersion = nVersion; return true; }
 
-    //! Adds a destination data tuple to the store, without saving it to disk
-    void LoadDestData(const CTxDestination& dest, const std::string& key, const std::string& value) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
+    //! Marks destination as previously spent.
+    void LoadAddressPreviouslySpent(const CTxDestination& dest) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
+    //! Appends payment request to destination.
+    void LoadAddressReceiveRequest(const CTxDestination& dest, const std::string& id, const std::string& request) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     //! Holds a timestamp at which point the wallet is scheduled (externally) to be relocked. Caller must arrange for actual relocking to occur via Lock().
     int64_t nRelockTime GUARDED_BY(cs_wallet){0};
@@ -739,11 +746,12 @@ public:
 
     bool DelAddressBook(const CTxDestination& address);
 
-    bool IsAddressUsed(const CTxDestination& dest) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
-    bool SetAddressUsed(WalletBatch& batch, const CTxDestination& dest, bool used) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
+    bool IsAddressPreviouslySpent(const CTxDestination& dest) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
+    bool SetAddressPreviouslySpent(WalletBatch& batch, const CTxDestination& dest, bool used) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     std::vector<std::string> GetAddressReceiveRequests() const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     bool SetAddressReceiveRequest(WalletBatch& batch, const CTxDestination& dest, const std::string& id, const std::string& value) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
+    bool EraseAddressReceiveRequest(WalletBatch& batch, const CTxDestination& dest, const std::string& id) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
     unsigned int GetKeyPoolSize() const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 
diff --git a/src/wallet/walletdb.cpp b/src/wallet/walletdb.cpp
index c8e8ce4614..005592d720 100644
--- a/src/wallet/walletdb.cpp
+++ b/src/wallet/walletdb.cpp
@@ -615,7 +615,20 @@ ReadKeyValue(CWallet* pwallet, DataStream& ssKey, CDataStream& ssValue,
             ssKey >> strAddress;
             ssKey >> strKey;
             ssValue >> strValue;
-            pwallet->LoadDestData(DecodeDestination(strAddress), strKey, strValue);
+            const CTxDestination& dest{DecodeDestination(strAddress)};
+            if (strKey.compare("used") == 0) {
+                // Load "used" key indicating if an IsMine address has
+                // previously been spent from with avoid_reuse option enabled.
+                // The strValue is not used for anything currently, but could
+                // hold more information in the future. Current values are just
+                // "1" or "p" for present (which was written prior to
+                // f5ba424cd44619d9b9be88b8593d69a7ba96db26).
+                pwallet->LoadAddressPreviouslySpent(dest);
+            } else if (strKey.compare(0, 2, "rr") == 0) {
+                // Load "rr##" keys where ## is a decimal number, and strValue
+                // is a serialized RecentRequestEntry object.
+                pwallet->LoadAddressReceiveRequest(dest, strKey.substr(2), strValue);
+            }
         } else if (strType == DBKeys::HDCHAIN) {
             CHDChain chain;
             ssValue >> chain;
@@ -1088,16 +1101,28 @@ void MaybeCompactWalletDB(WalletContext& context)
     fOneThread = false;
 }
 
-bool WalletBatch::WriteDestData(const std::string &address, const std::string &key, const std::string &value)
+bool WalletBatch::WriteAddressPreviouslySpent(const CTxDestination& dest, bool previously_spent)
+{
+    auto key{std::make_pair(DBKeys::DESTDATA, std::make_pair(EncodeDestination(dest), std::string("used")))};
+    return previously_spent ? WriteIC(key, std::string("1")) : EraseIC(key);
+}
+
+bool WalletBatch::WriteAddressReceiveRequest(const CTxDestination& dest, const std::string& id, const std::string& receive_request)
 {
-    return WriteIC(std::make_pair(DBKeys::DESTDATA, std::make_pair(address, key)), value);
+    return WriteIC(std::make_pair(DBKeys::DESTDATA, std::make_pair(EncodeDestination(dest), "rr" + id)), receive_request);
 }
 
-bool WalletBatch::EraseDestData(const std::string &address, const std::string &key)
+bool WalletBatch::EraseAddressReceiveRequest(const CTxDestination& dest, const std::string& id)
 {
-    return EraseIC(std::make_pair(DBKeys::DESTDATA, std::make_pair(address, key)));
+    return EraseIC(std::make_pair(DBKeys::DESTDATA, std::make_pair(EncodeDestination(dest), "rr" + id)));
 }
 
+bool WalletBatch::EraseAddressData(const CTxDestination& dest)
+{
+    DataStream prefix;
+    prefix << DBKeys::DESTDATA << EncodeDestination(dest);
+    return m_batch->ErasePrefix(prefix);
+}
 
 bool WalletBatch::WriteHDChain(const CHDChain& chain)
 {
diff --git a/src/wallet/walletdb.h b/src/wallet/walletdb.h
index c97356a71f..72086e950a 100644
--- a/src/wallet/walletdb.h
+++ b/src/wallet/walletdb.h
@@ -7,6 +7,7 @@
 #define BITCOIN_WALLET_WALLETDB_H
 
 #include <script/sign.h>
+#include <script/standard.h>
 #include <wallet/db.h>
 #include <wallet/walletutil.h>
 #include <key.h>
@@ -264,10 +265,10 @@ public:
     bool WriteLockedUTXO(const COutPoint& output);
     bool EraseLockedUTXO(const COutPoint& output);
 
-    /// Write destination data key,value tuple to database
-    bool WriteDestData(const std::string &address, const std::string &key, const std::string &value);
-    /// Erase destination data tuple from wallet database
-    bool EraseDestData(const std::string &address, const std::string &key);
+    bool WriteAddressPreviouslySpent(const CTxDestination& dest, bool previously_spent);
+    bool WriteAddressReceiveRequest(const CTxDestination& dest, const std::string& id, const std::string& receive_request);
+    bool EraseAddressReceiveRequest(const CTxDestination& dest, const std::string& id);
+    bool EraseAddressData(const CTxDestination& dest);
 
     bool WriteActiveScriptPubKeyMan(uint8_t type, const uint256& id, bool internal);
     bool EraseActiveScriptPubKeyMan(uint8_t type, bool internal);