wallet: sqlite migration, write multi

src/wallet/bdb.h

@@ -206,6 +206,7 @@ class BerkeleyBatch : public DatabaseBatch
     bool TxnCommit() override;
     bool TxnAbort() override;
     DbTxn* txn() const { return activeTxn; }
+    bool WriteMulti(const std::vector<std::pair<SerializeData, SerializeData>>& records) override { return false; }
 };
 
 std::string BerkeleyDatabaseVersion();

src/wallet/db.h

@@ -116,6 +116,8 @@ class DatabaseBatch
     virtual bool TxnBegin() = 0;
     virtual bool TxnCommit() = 0;
     virtual bool TxnAbort() = 0;
+
+    virtual bool WriteMulti(const std::vector<std::pair<SerializeData, SerializeData>>& records) = 0;
 };
 
 /** An instance of this class represents one database.

src/wallet/salvage.cpp

@@ -44,6 +44,7 @@ class DummyBatch : public DatabaseBatch
     bool TxnBegin() override { return true; }
     bool TxnCommit() override { return true; }
     bool TxnAbort() override { return true; }
+    bool WriteMulti(const std::vector<std::pair<SerializeData, SerializeData>>& records) override { return false; }
 };
 
 /** A dummy WalletDatabase that does nothing and never fails. Only used by salvage.

src/wallet/sqlite.cpp

@@ -646,6 +646,49 @@ std::unique_ptr<DatabaseCursor> SQLiteBatch::GetNewPrefixCursor(Span<const std::
     return cursor;
 }
 
+bool SQLiteBatch::WriteMulti(const std::vector<std::pair<SerializeData, SerializeData>>& records)
+{
+    LogPrintf("###### WriteMulti, records size %d #######\n", records.size());
+    // Prepare statement
+    std::string multi_line_insert = "INSERT INTO main VALUES(?, ?)";
+    for (size_t i=1; i<records.size(); i++) multi_line_insert += ", (?, ?)";
+    multi_line_insert += ";";
+
+    sqlite3_stmt* stmt{nullptr};
+    int res = sqlite3_prepare_v2(m_database.m_db, multi_line_insert.c_str(), -1, &stmt, nullptr);
+    if (res != SQLITE_OK) {
+        LogPrintf("Failed to prepare multi insert statement\n");
+        return false;
+    }
+
+    // Bind data
+    int pos = 0;
+    for (size_t i = 0; i < records.size(); i++) {
+        const auto& [key, value] = records.at(i);
+        assert(BindBlobToStatement(stmt, ++pos, key, "key"));
+        assert(BindBlobToStatement(stmt, ++pos, value, "value"));
+    }
+
+    // Execute
+    res = sqlite3_step(stmt);
+    sqlite3_clear_bindings(stmt);
+    sqlite3_reset(stmt);
+    if (res != SQLITE_DONE) {
+        LogPrintf("Failed to insert multi insert statement, res: %s, code %d\n", sqlite3_errstr(res), res);
+        return false;
+    }
+
+    // Clear
+    res = sqlite3_finalize(stmt);
+    if (res != SQLITE_OK) {
+        LogPrintf("Failed to finalize multi insert statement\n");
+        return false;
+    }
+    stmt = nullptr;
+
+    return true;
+}
+
 bool SQLiteBatch::TxnBegin()
 {
     if (!m_database.m_db || m_txn) return false;

src/wallet/sqlite.h

@@ -95,6 +95,8 @@ class SQLiteBatch : public DatabaseBatch
     bool TxnBegin() override;
     bool TxnCommit() override;
     bool TxnAbort() override;
+
+    bool WriteMulti(const std::vector<std::pair<SerializeData, SerializeData>>& records) override;
 };
 
 /** An instance of this class represents one SQLite3 database.

src/wallet/test/util.h

@@ -93,6 +93,8 @@ class MockableBatch : public DatabaseBatch
     bool TxnBegin() override { return m_pass; }
     bool TxnCommit() override { return m_pass; }
     bool TxnAbort() override { return m_pass; }
+    bool WriteMulti(const std::vector<std::pair<SerializeData, SerializeData>>& records) override { return false; }
+
 };
 
 /** A WalletDatabase whose contents and return values can be modified as needed for testing

src/wallet/wallet.cpp

@@ -3907,13 +3907,11 @@ bool CWallet::MigrateToSQLite(bilingual_str& error)
     batch = m_database->MakeBatch();
     bool began = batch->TxnBegin();
     assert(began); // This is a critical error, the new db could not be written to. The original db exists as a backup, but we should not continue execution.
-    for (const auto& [key, value] : records) {
-        if (!batch->Write(Span{key}, Span{value})) {
-            batch->TxnAbort();
-            m_database->Close();
-            fs::remove(m_database->Filename());
-            assert(false); // This is a critical error, the new db could not be written to. The original db exists as a backup, but we should not continue execution.
-        }
+    if (!batch->WriteMulti(records)) {
+        batch->TxnAbort();
+        m_database->Close();
+        fs::remove(m_database->Filename());
+        assert(false); // This is a critical error, the new db could not be written to. The original db exists as a backup, but we should not continue execution.
     }
     bool committed = batch->TxnCommit();
     assert(committed); // This is a critical error, the new db could not be written to. The original db exists as a backup, but we should not continue execution.