A million of rows in ExtJS infinite grid (strange effect) - extjs

Question

I've made an application with ExtJS infinite grid like this example.
My application receives data from a database.
It worked perfectly with the small amounts of rows (by 100000).
But now a database contains one million of rows. And I observed a strange effect: data are not loaded completely. Each time the grid shows different number of rows (maximum 859176). But I need to load all rows from a database.
Does anybody know how to solve this problem?
My code:
Ext.require ([
'Ext.grid.*',
'Ext.data.*',
'Ext.util.*',
'Ext.grid.plugin.BufferedRenderer'
]);
Ext.onReady(function () {
Ext.define('DoctorsList', {
extend: 'Ext.data.Model',
fields: [
'id', 'fio', 'specialization', 'photo'
],
idProperty: 'id'
});
var store = Ext.create('Ext.data.Store', {
id: 'store',
model: 'DoctorsList',
buffered: true,
pageSize: 100,
proxy: {
type: 'ajax',
url: 'get_doctors.jsp',
reader: {
root: 'data',
totalProperty: 'total'
}
},
autoLoad: true
});
Ext.create('Ext.grid.Panel', {
height: 600,
title: 'Doctor\'s list',
collapsible: true,
store: store,
columns: [
{
text: 'ID',
dataIndex: 'id',
width: 50,
sortable: true
},
{
text: 'Full name',
dataIndex: 'fio',
width: 300,
sortable: true
},
{
text: 'Specialization',
dataIndex: 'specialization',
width: 150,
sortable: true
},
{
text: 'Photo',
dataIndex: 'photo',
width: 100,
sortable: false,
renderer: function(value) {
return '<img width="100" src="images/' + value + '" />';
}
}
],
renderTo: 'doctors-list'
});
});
ADDITION:
Here you can see last request and response to get_doctors.jsp. You can notice there that the field 'total' has number 1005000 but last row has ID 423165. And here is the screen of MS SQL database selection. You can see there that used table has 1005000 rows totally.
ADDITION 2:
This bug appears in Firefox and IE8, but it does not appear in Opera, Google Chrome and Safari.
Thanks!