QSortFilterProxyModel invalidate is slow when there's a large number of persistent indicies

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class&amp;gt;MainWindow</class&amp;gt;
 <widget class="QMainWindow" name="MainWindow">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>800</width>
    <height>600</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>MainWindow</string>
  </property>
  <widget class="QWidget" name="centralwidget">
   <layout class="QVBoxLayout" name="verticalLayout">
    <item>
     <widget class="QTableView" name="tableView">
      <property name="selectionBehavior">
       <enum>QAbstractItemView::SelectRows</enum>
      </property>
     </widget>
    </item>
    <item>
     <widget class="QPushButton" name="pushButton">
      <property name="text">
       <string>Invalidate</string>
      </property>
     </widget>
    </item>
   </layout>
  </widget>
 </widget>
 <resources/>
 <connections/>
</ui> 

#ifndef TESTTABLE_H
#define TESTTABLE_H

#include <QAbstractTableModel>

class TestTable : public QAbstractTableModel
{
    Q_OBJECT

public:
    explicit TestTable(QObject *parent = nullptr);

    // Header:
    QVariant headerData(int section, Qt::Orientation orientation, int role = Qt::DisplayRole) const override;

    // Basic functionality:
    int rowCount(const QModelIndex &parent = QModelIndex()) const override;
    int columnCount(const QModelIndex &parent = QModelIndex()) const override;

    QVariant data(const QModelIndex &index, int role = Qt::DisplayRole) const override;

private:
};

#endif // TESTTABLE_H

#include "testtable.h"

TestTable::TestTable(QObject *parent)
    : QAbstractTableModel(parent)
{
}

QVariant TestTable::headerData(int section, Qt::Orientation orientation, int role) const
{
    return QString::number(section);
}

int TestTable::rowCount(const QModelIndex &parent) const
{
    if (parent.isValid())
        return 0;

    return 200;
}

int TestTable::columnCount(const QModelIndex &parent) const
{
    if (parent.isValid())
        return 0;

    return 200;
}

QVariant TestTable::data(const QModelIndex &index, int role) const
{
    if (!index.isValid())
        return QVariant();

    return QString("%1 - %2").arg(index.row()).arg(index.column());
} 

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE
class TestTable;
class QSortFilterProxyModel;

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;
    TestTable *model;
    QSortFilterProxyModel *proxy;
};
#endif // MAINWINDOW_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "testtable.h"

#include <QSortFilterProxyModel>

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
    , model(new TestTable)
    , proxy(new QSortFilterProxyModel)
{
    ui->setupUi(this);

    proxy->setSourceModel(model);
    ui->tableView->setModel(proxy);

    QObject::connect(ui->pushButton, &QPushButton::clicked, proxy, &QSortFilterProxyModel::invalidate);
}

MainWindow::~MainWindow()
{
    delete ui;
} 

#include "mainwindow.h"

#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
}