title: Qt widget for displaying large amount of data rows
body: <p>I am trying to display a large amount of columnar records in a scrollable view using Qt (5.1).</p>
  
  <p>The number of rows I would like to be able to browse can vary from 100 million to 1 Billion, say. </p>
  
  <p>The QTableWidget with a custom model works a few million rows, but the QTableWidget allocates data for each row because you can re-size the rows height, and so it must store data for this, which can use megabytes or even gigabytes of memory with 100M rows. </p>
  
  <p>I do not require the re-sizeable rows functionality just a multi-column list would be ideal, but QTreeCtrl doesnt seem to work with many rows, and QList seems to only support single columns.</p>
  
  <p>Should I be implementing a custom widget from  QAbstractItemView for this purpose?</p>
  
  <p>For those familiar with wxwidgets/wepython it can be done like this, and works well with billions of rows:</p>
  
  <pre><code>import wx
  
  class VirtualList(wx.ListCtrl):
  
      def __init__(self, parent, id, pos, size, flags):
          wx.ListCtrl.__init__(self, parent, id, pos, size, flags)
  
      def OnGetItemText(self, item, column):
          return "Row %d, Column %d" % (item, column)
  </code></pre>