Inconsistent data corruption in a store loaded through a proxy reader - ajax

Question

We're experiencing inconsistent data corruption in a store loaded through a proxy reader.
It's browser dependant.
Works fine in Chrome and Safari on the desktop all the time.
On our two testing iPhones it intermittently breaks depending on the data the store has loaded, larger data volume seems to cause more breaks. We can't see any errors or patterns in the JSON data where it breaks.
Symptoms:
data loads, but some of the data belonging to the last few items is missing
a read listener attached to the store doesn't fire when this data loss occurs, it does fire on the desktop browser where we experience not data loss
The piece of data that always seems to be lost is the start_time.
We've been trying to debug this one for a while now and are really stumped.
Thank you for any ideas you might have as to why this is occurring.
Our regModel
Ext.regModel('Booking', {
fields: ['id', 'start', 'end', 'title', 'service', 'service_id', 'client_note', 'stylist_note', 'utc_start','day_date', 'start_time', 'end_time', "home_ph", "mobile_ph", 'work_ph', 'work_ext', 'email', 'utc_end']
});
Our store
var store = new Ext.data.JsonStore({
model : 'Booking',
sorters: 'utc_start',
autoLoad: false,
proxy: {
type: 'ajax',
url: '../includes/get_appointments.php',
extraParams: {
req_start: '1295251200',
req_end: '1295856000'
},
reader: {
type: 'json',
root: 'events'
}
},
listeners: {
load:function(store, records, success) {
bookings.setLoading(false);
// check to see length of records, start i from there
for (var i = 0; i < records.length; i++){
utc_start = records[i].get('utc_start');
utc_end = records[i].get('utc_end');
// create day of week
// y,m,d
// time
var this_start_date = new Date((utc_start * 1000));
var this_end_date = new Date((utc_end * 1000));
var day_of_week = days_of_week[this_start_date.getDay()];
var date_of_month = this_start_date.getDate();
var month_of_year = month_names[this_start_date.getMonth()];
var full_year = this_start_date.getFullYear();
var start_military_hours = this_start_date.getHours();
var this_start_minutes = this_start_date.getMinutes();
var end_military_hours = this_end_date.getHours();
var this_end_minutes = this_end_date.getMinutes();
if(this_start_minutes == "0")
{
this_start_minutes = "00";
}
if(parseInt(start_military_hours) < 12)
{
var start_time = start_military_hours + ":" + this_start_minutes + " AM";
}
else if(parseInt(start_military_hours) == 12)
{
var start_time = start_military_hours + ":" + this_start_minutes + " PM";
}
else
{
var start_time = (parseInt(start_military_hours) - 12) + ":" + this_start_minutes + " PM";
}
if(this_end_minutes == "0")
{
this_end_minutes = "00";
}
if(parseInt(end_military_hours) < 12)
{
var end_time = end_military_hours + ":" + this_end_minutes + " AM";
}
else if(parseInt(end_military_hours) == 12)
{
var end_time = end_military_hours + ":" + this_end_minutes + " PM";
}
else
{
var end_time = (parseInt(end_military_hours) - 12) + ":" + this_end_minutes + " PM";
}
var day_date = day_of_week + ", " + full_year + " " + month_of_year + " " + date_of_month;
if(records[i].get('service_id') == 0)
{
records[i].set('title', 'Booked off');
records[i].set('service', '');
}
records[i].set('day_date', day_date);
records[i].set('start_time', start_time);
records[i].set('end_time', end_time);
}
if(store.proxy.reader.rawData.next_page_num == undefined)
{
store.start = store.proxy.reader.rawData.prev_page_num;
}
else
{
store.currentPage = store.proxy.reader.rawData.next_page_num;
}
}, read:function(store,records,success){
Ext.Msg.alert('data read');
}
},
getGroupString : function(record) {
return record.get('day_date'); // optional char from array removed
}
});
Our JSON
{"events":[{"id":"3739","start":"2011-01-18T10:00:00-08:00","end":"2011-01-18T11:45:00-08:00","title":"Jen Cannor","service":"Haircut & Highlights","service_id":"67","client_note":"","stylist_note":"Looking forward to seeing Jen when she comes in next.","utc_start":"1295373600","email":"jen.c#cannorfarms.net","home_ph":"232-433-2222","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1295379900"},{"id":"3740","start":"2011-01-18T12:00:00-08:00","end":"2011-01-18T13:30:00-08:00","title":"Michelle Steves","service":"Root Colour","service_id":"69","client_note":"","stylist_note":"","utc_start":"1295380800","email":"michelle5b64#telus.net","home_ph":"604-555-5555","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1295386200"},{"id":"3741","start":"2011-01-18T13:30:00-08:00","end":"2011-01-18T14:00:00-08:00","title":"Amanda Brenner","service":"Wash & blow dry","service_id":"70","client_note":"","stylist_note":"","utc_start":"1295386200","email":"amandab#coastfitness.com","home_ph":"555-235-2366","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1295388000"},{"id":"3742","start":"2011-01-18T14:00:00-08:00","end":"2011-01-18T15:45:00-08:00","title":"Janice Potters","service":"Haircut & Colour","service_id":"66","client_note":"","stylist_note":"","utc_start":"1295388000","email":"","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1295394300"},{"id":"3743","start":"2011-01-18T15:45:00-08:00","end":"2011-01-18T16:45:00-08:00","title":"Angus Middleton","service":"Men's haircut","service_id":"61","client_note":"","stylist_note":"","utc_start":"1295394300","email":"angusman#hotmaile.com","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1295397900"},{"id":"3025","start":"2011-01-19T08:00:00-08:00","end":"2011-01-19T09:45:00-08:00","title":"Jen Cannor","service":"Haircut & Highlights","service_id":"67","client_note":"","stylist_note":"","utc_start":"1295452800","email":"jen.c#cannorfarms.net","home_ph":"232-433-2222","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1295459100"},{"id":"3026","start":"2011-01-19T10:00:00-08:00","end":"2011-01-19T11:45:00-08:00","title":"Karen Walker","service":"Haircut & Colour","service_id":"66","client_note":"","stylist_note":"","utc_start":"1295460000","email":"karenwalker#officesurplusdirect.net","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1295466300"},{"id":"3027","start":"2011-01-19T11:45:00-08:00","end":"2011-01-19T12:45:00-08:00","title":"Amanda Brenner","service":"Women's Haircut","service_id":"65","client_note":"","stylist_note":"","utc_start":"1295466300","email":"amandab#coastfitness.com","home_ph":"555-235-2366","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1295469900"},{"id":"3028","start":"2011-01-19T13:00:00-08:00","end":"2011-01-19T14:30:00-08:00","title":"Mary Thacker","service":"Root Colour","service_id":"69","client_note":"","stylist_note":"","utc_start":"1295470800","email":"","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1295476200"},{"id":"3029","start":"2011-01-19T14:30:00-08:00","end":"2011-01-19T15:00:00-08:00","title":"Malcolm Anderson","service":"Men's haircut","service_id":"61","client_note":"","stylist_note":"","utc_start":"1295476200","email":"malcolm#testserveraddy.com","home_ph":"240-444-4444","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1295478000"},{"id":"4856","start":"2011-03-09T09:00:00-08:00","end":"2011-03-09T10:00:00-08:00","title":"Simon Chalk","service":"Men's haircut","service_id":"61","client_note":"","stylist_note":"","utc_start":"1299690000","email":"","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299693600"},{"id":"4858","start":"2011-03-09T10:00:00-08:00","end":"2011-03-09T10:15:00-08:00","title":"Brian Lytton","service":"Men's haircut","service_id":"61","client_note":"","stylist_note":"","utc_start":"1299693600","email":"","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299694500"},{"id":"4859","start":"2011-03-09T10:15:00-08:00","end":"2011-03-09T10:30:00-08:00","title":"Brad Wicker","service":"Men's haircut","service_id":"61","client_note":"","stylist_note":"","utc_start":"1299694500","email":"","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299695400"},{"id":"4860","start":"2011-03-09T10:30:00-08:00","end":"2011-03-09T10:45:00-08:00","title":"Brad Wicker","service":"Men's haircut","service_id":"61","client_note":"","stylist_note":"","utc_start":"1299695400","email":"","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299696300"},{"id":"4861","start":"2011-03-09T10:45:00-08:00","end":"2011-03-09T11:00:00-08:00","title":"Brian Lytton","service":"Men's haircut","service_id":"61","client_note":"","stylist_note":"","utc_start":"1299696300","email":"","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299697200"},{"id":"4862","start":"2011-03-09T11:00:00-08:00","end":"2011-03-09T11:15:00-08:00","title":"Brian Lytton","service":"Men's haircut","service_id":"61","client_note":"","stylist_note":"","utc_start":"1299697200","email":"","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299698100"},{"id":"4863","start":"2011-03-09T11:15:00-08:00","end":"2011-03-09T11:30:00-08:00","title":"Simon Chalk","service":"Men's haircut","service_id":"61","client_note":"","stylist_note":"","utc_start":"1299698100","email":"","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299699000"},{"id":"4864","start":"2011-03-09T11:30:00-08:00","end":"2011-03-09T11:45:00-08:00","title":"Chester Welling","service":"Men's haircut","service_id":"61","client_note":"","stylist_note":"","utc_start":"1299699000","email":"chester#eastern.pharma.net","home_ph":"604-555-5555","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299699900"},{"id":"4865","start":"2011-03-09T11:45:00-08:00","end":"2011-03-09T12:00:00-08:00","title":"Brad Wicker","service":"Men's haircut","service_id":"61","client_note":"","stylist_note":"","utc_start":"1299699900","email":"","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299700800"},{"id":"4866","start":"2011-03-09T12:00:00-08:00","end":"2011-03-09T13:00:00-08:00","title":"Janice Potters","service":"Women's Haircut","service_id":"65","client_note":"","stylist_note":"","utc_start":"1299700800","email":"","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299704400"},{"id":"4867","start":"2011-03-09T13:00:00-08:00","end":"2011-03-09T13:15:00-08:00","title":"Jacqui Chan","service":"Women's Haircut","service_id":"65","client_note":"","stylist_note":"","utc_start":"1299704400","email":"jc#rebelfrontier.net","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299705300"},{"id":"4876","start":"2011-03-09T13:15:00-08:00","end":"2011-03-09T13:30:00-08:00","title":"Mary Thacker","service":"Women's Haircut","service_id":"65","client_note":"","stylist_note":"","utc_start":"1299705300","email":"","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299706200"},{"id":"4868","start":"2011-03-10T10:15:00-08:00","end":"2011-03-10T11:15:00-08:00","title":"Trisha Roberts","service":"Women's Haircut","service_id":"65","client_note":"","stylist_note":"","utc_start":"1299780900","email":"trb483408#gmail.com","home_ph":"604-555-5555","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299784500"},{"id":"4870","start":"2011-03-10T11:30:00-08:00","end":"2011-03-10T12:30:00-08:00","title":"Jenson Bryant","service":"Women's Haircut","service_id":"65","client_note":"","stylist_note":"","utc_start":"1299785400","email":"","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299789000"},{"id":"4872","start":"2011-03-10T12:45:00-08:00","end":"2011-03-10T13:00:00-08:00","title":"Jenson Bryant","service":"Women's Haircut","service_id":"65","client_note":"","stylist_note":"","utc_start":"1299789900","email":"","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299790800"},{"id":"4873","start":"2011-03-10T13:00:00-08:00","end":"2011-03-10T13:15:00-08:00","title":"Jenson Bryant","service":"Women's Haircut","service_id":"65","client_note":"","stylist_note":"","utc_start":"1299790800","email":"","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299791700"},{"id":"4874","start":"2011-03-10T13:15:00-08:00","end":"2011-03-10T14:15:00-08:00","title":"Simon Chalk","service":"Men's haircut","service_id":"61","client_note":"","stylist_note":"","utc_start":"1299791700","email":"","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299795300"},{"id":"4875","start":"2011-03-11T10:15:00-08:00","end":"2011-03-11T11:15:00-08:00","title":"Karen Walker","service":"Women's Haircut","service_id":"65","client_note":"","stylist_note":"","utc_start":"1299867300","email":"karenwalker#officesurplusdirect.net","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299870900"},{"id":"4877","start":"2011-03-11T12:00:00-08:00","end":"2011-03-11T12:15:00-08:00","title":"Amanda Brenner","service":"Women's Haircut","service_id":"65","client_note":"","stylist_note":"","utc_start":"1299873600","email":"amandab#coastfitness.com","home_ph":"555-235-2366","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299874500"},{"id":"4878","start":"2011-03-11T12:30:00-08:00","end":"2011-03-11T13:30:00-08:00","title":"Arnold Fieldman","service":"Men's haircut","service_id":"61","client_note":"","stylist_note":"","utc_start":"1299875400","email":"","home_ph":"","mobile_ph":"","work_ph":"","work_ext":"","utc_end":"1299879000"}], "next_page_num":"7"}

Answer 1

This is not a Sencha Touch specific issue: there are limits on the size of Ajax response that mobile safari can handle: see Too large an AJAX response for mobile safari?
Update: apparently this is not a mobile safari problem, this is a cellular network problem. Some networks will helpfully "paginate" the Ajax call -- thinking it's a regular web page download. Can you check to see if this is still the case on a wifi network?

Answer 2

After much head banging it appears that Sencha Touch stores only work well with up to approximately 10,000 characters I'm guess 8192 + the json delimiters?
After that it seems to start losing part of the data for us.
Can anyone else corroborate this?