gui: Optimize OverviewPage::updateTransactions()

src/qt/overviewpage.cpp

@@ -161,16 +161,46 @@ void OverviewPage::showEvent(QShowEvent *event)
     updateTransactions();
 }
 
+int OverviewPage::getNumTransactionsForView()
+{
+    // Compute the maximum number of transactions the transaction list widget
+    // can hold without overflowing.
+    const size_t itemHeight = DECORATION_SIZE + ui->listTransactions->spacing();
+    const size_t contentsHeight = ui->listTransactions->height();
+    const int numItems = contentsHeight / itemHeight;
+
+    return numItems;
+}
+
+
 void OverviewPage::updateTransactions()
 {
-    if(filter)
+    if (filter)
     {
-        // Show the maximum number of transactions the transaction list widget
-        // can hold without overflowing.
-        const size_t itemHeight = DECORATION_SIZE + ui->listTransactions->spacing();
-        const size_t contentsHeight = ui->listTransactions->height();
-        const size_t numItems = contentsHeight / itemHeight;
-        filter->setLimit(numItems);
+        int numItems = getNumTransactionsForView();
+
+        // This is a "stairstep" approach, using x3 to x6 factors to size the setLimit.
+        // Based on testing with a wallet with a large number of transactions (40k+)
+        // Using a factor of three is a good balance between the setRowHidden loop
+        // and the very high expense of the getLimit call, which invalidates the filter
+        // and sort, and implicitly redoes the sort, which can take seconds for a large
+        // wallet.
+
+        // Most main window resizes will be done without an actual call to setLimit.
+        if (filter->getLimit() < numItems)
+        {
+            filter->setLimit(numItems * 3);
+        }
+        else if (filter->getLimit() > numItems * 6)
+        {
+            filter->setLimit(numItems * 3);
+        }
+
+        for (int i = 0; i <= filter->getLimit(); ++i)
+        {
+            ui->listTransactions->setRowHidden(i, i >= numItems);
+        }
+
         ui->listTransactions->update();
     }
 }
@@ -240,8 +270,8 @@ void OverviewPage::setWalletModel(WalletModel *model)
         filter->setDynamicSortFilter(true);
         filter->setSortRole(Qt::EditRole);
         filter->setShowInactive(false);
+        filter->setLimit(getNumTransactionsForView());
         filter->sort(TransactionTableModel::Status, Qt::DescendingOrder);
-
         ui->listTransactions->setModel(filter.get());
         ui->listTransactions->setModelColumn(TransactionTableModel::ToAddress);
 
@@ -250,6 +280,9 @@ void OverviewPage::setWalletModel(WalletModel *model)
         connect(model, SIGNAL(balanceChanged(qint64, qint64, qint64, qint64)), this, SLOT(setBalance(qint64, qint64, qint64, qint64)));
 
         connect(model->getOptionsModel(), SIGNAL(displayUnitChanged(int)), this, SLOT(updateDisplayUnit()));
+
+        connect(model, SIGNAL(transactionUpdated()), this, SLOT(updateTransactions()));
+
         UpdateBoincUtilization();
     }
 

src/qt/overviewpage.h

@@ -47,7 +47,7 @@ public slots:
     void showEvent(QShowEvent *event);
 
 private:
-    void updateTransactions();
+    int getNumTransactionsForView();
 
     Ui::OverviewPage *ui;
     ResearcherModel *researcherModel;
@@ -62,6 +62,7 @@ public slots:
 
 private slots:
     void updateDisplayUnit();
+    void updateTransactions();
     void updateResearcherStatus();
     void updateMagnitude();
     void updatePendingAccrual();

src/qt/transactionfilterproxy.cpp

@@ -87,6 +87,11 @@ void TransactionFilterProxy::setLimit(int limit)
     invalidate();
 }
 
+int TransactionFilterProxy::getLimit()
+{
+    return this->limitRows;
+}
+
 void TransactionFilterProxy::setShowInactive(bool showInactive)
 {
     this->showInactive = showInactive;

src/qt/transactionfilterproxy.h

@@ -31,6 +31,9 @@ class TransactionFilterProxy : public QSortFilterProxyModel
     /** Set maximum number of rows returned, -1 if unlimited. */
     void setLimit(int limit);
 
+    /** Get maximum number of rows returned, -1 if unlimited. */
+    int getLimit();
+
     /** Set whether to show conflicted transactions. */
     void setShowInactive(bool showInactive);
 

src/qt/transactiontablemodel.cpp

@@ -115,7 +115,8 @@ class TransactionTablePriv
                     status = CT_DELETED; /* In model, but want to hide, treat as deleted */
             }
 
-            LogPrint(BCLog::LogFlags::VERBOSE, "   inWallet=%i inModel=%i Index=%i-%i showTransaction=%i derivedStatus=%i",                     inWallet, inModel, lowerIndex, upperIndex, showTransaction, status);
+            LogPrint(BCLog::LogFlags::VERBOSE, "   inWallet=%i inModel=%i Index=%i-%i showTransaction=%i derivedStatus=%i",
+                     inWallet, inModel, lowerIndex, upperIndex, showTransaction, status);
 
 
             switch(status)

src/qt/walletmodel.cpp

@@ -126,16 +126,24 @@ void WalletModel::checkBalanceChanged()
 
 void WalletModel::updateTransaction(const QString &hash, int status)
 {
-    if(transactionTableModel)
+    if (transactionTableModel)
+    {
         transactionTableModel->updateTransaction(hash, status);
 
+        // Note this is subtly different than the below. If a resync is being done on a wallet
+        // that already has transactions, the numTransactionsChanged will not be emitted after the
+        // wallet is loaded because the size() does not change. See the comments in the header file.
+        emit transactionUpdated();
+    }
+
     // Balance and number of transactions might have changed
     checkBalanceChanged();
 
     int newNumTransactions = getNumTransactions();
-    if(cachedNumTransactions != newNumTransactions)
+    if (cachedNumTransactions != newNumTransactions)
     {
         cachedNumTransactions = newNumTransactions;
+
         emit numTransactionsChanged(newNumTransactions);
     }
 }

src/qt/walletmodel.h

@@ -163,6 +163,11 @@ public slots:
     void pollBalanceChanged();
 
 signals:
+    // Transaction updated. This is necessary because on a resync from zero with an existing wallet.
+    // the numTransactionsChanged signal will not be emitted, and therefore the overpage transaction list
+    // needs this signal instead.
+    void transactionUpdated();
+
     // Signal that balance in wallet changed
     void balanceChanged(qint64 balance, qint64 stake, qint64 unconfirmedBalance, qint64 immatureBalance);