XOJO cloud small load limits?

I have a completely quiet Xojo Cloud server.

Buy quiet I mean no database services, no Secure tunnel nothing running

I restarted the server to make sure there was nothing running.

I then put a very simple application on it one window with one label that says hello World

I then Open chrome and tried to open 10 instances of that application

The first four or five go off fine

After that everything seems to just hang. The browsers all hang within message “waiting for socket”

Is there some sort of bottleneck in chrome, safari, and IE that is causing this?


Ok first of all, keep in mind that all of your windows share the same cookie cache within the same browser, so technically all of these Windows are accessing the same exact session. Because of this, you’re likely confusing the back-end as to what the actual state of the front-end is supposed to be.

If you want to do something like this, I suggest using multiple browsers. If you need more, use virtual machines through Parallels, VMWare or VirtualBox.

I don’t use Xojo Cloud services, but we do test our server farm with a specially crafted Linux server running 50 VirtualBox containers with Linux and Windows instances. in each instance, we kick off each of that platform’s supported browser and that gives us around 170 connections to our web services - JS, PHP, Xojo, scripted CGI, and compiled tools.

That costs nothing but a machine powerful enough to run the sessions (we use a dual processor Xeon system with 64GB of RAM) and some time to configure things.


I would love to point your Xeon box at my XC instance…

I’d love to help others, but it’s in our green network and can’t chatter outside of our firewall.

@Greg O’Lone My users frequently run 3 or 4 tabs in their browsers. Is this bad? How to manage?

I assume third party services that are used to just looking at pages are not valid tests?


I can confirm that it is in fact as Greg says something other than the xojo cloud/rack space itself

We tried the same test on a number of different clinics-based providers and once you try to open up multiple tabs anything ever about five or six starts to stall out

That’s an interesting test. Given the above, I wonder if you find that things don’t stall out in the same way if you use multiple browsers in a similar usage scenario (like Safari/Firefox/Chrome/Edge/etc)- rather than multiple tabs.

If you set/use cookies- those are by definition per-browser and not per-tab and could be confusing things. Just another thing to keep in mind as you push through. Since cookies are per-browser, you could use a cookie to track how many active sessions (tabs) the person has in that browser (by incrementing/decrementing on session creation or login/logout) and limit them to 1 or 2 apiece. That way you and they aren’t running into any browser Javascript throttling limits either (which can impact you after a certain number of tabs to the same place- and unfortunately aren’t completely standard). Constant Javascript communication is the lifeblood of the Xojo web framework.

A few years ago i did test this and then i reported that this is a limitation of the browser. In my tests Safari was the first to stall with 5 to 6 tabs, FF could handle about 7 sometimes 8. However if you use seperate windows then you will see that the limit is per tab and not per window, every window then could handle about the same number of tabs, Safari every new window could handle about 5 sessions in different tabs and FF about 7.
In my case the server did accept and handle much more sessions than i could start in ca 5 different browsers all together.
Among those browsers were Safari, FF, IE, Chrome and Opera.
The best browser for handling many pictures (photo’s) upto about 750 was IE, even with that number of pictures in 5 scrolling container controls moving/scrolling still was in iE smooth while all others were stumbling from one picture to the next. Loading times however was in all browsers, as to be expected, extremely slow.

Yeah, in fact I think it was your (Andre’s) data that I was reminded of when reading this thread. Browsers have per-tab/per-location limits on rendering and Javascript execution which can impact all realtime web apps (not just Xojo).

Just to help with the testing, some browsers (FF and Chrome, at least) allow to do “private browsing” (or “incognito mode”) and I BELIEVE any new private window is independent of the previously open ones, though I must admit I know next to nothing about how the web works.

For example you can login to different outlook/hotmail accounts simultaneously using private browsing, which is not possible otherwise.



I just tried Julen’s process and I was able to open 15 tabs in Chrome to one of my servers when non-incognito tabs stalled at 6.

I never thought of that, but it could have saved us a lot of frustration in our testing and load environment back in 2011 …