Backtest runner very flaky?

I know the feeling, but it's usually something trivial.

Assuming 1) you are using the cloud backtester, and 2) running in chrome it's likely an error in the code somewhere. Hard to say what's going wrong without seeing it.

Also, is the issue happening with every single strategy you try to run, or just yours?

I recommend cloning a few of the many backtests shared in the forum and trying to run them.

Like this one that Derek just recently shared:

https://www.quantconnect.com/forum/discussion/14220/donchian-channel-breakout-strategy/p1

Just click clone to copy it, then run it.

Report back and let us know if they work (and also confirm assumptions above) If they all are inconsistent, please share more details.

Hey John Gillespie,

.ekz. is right, it happens to all of us.

There's a few things you can do to have less problems assuming that your code is correct. If you have the ‘waiting for chart’ error you can simply deselect and select again the box that wont load in the CHART box(where all boxes are listed). Also make sure to not run your backtests right after you already run one. Give it some time and click the build project button before running another test. 

Thanks for the responses .ekz. and Nico Xenox .

1. I am using cloud backtester via Chrome.
2. The exact same code will work fine, then it won't work, then it will work, etc etc.

What Nico has described is exactly what I'm seeing, if I deselect the check box and reselect, the chart will then load. But the Orders list won't load and I have to redo the backtest. 

It feels like some sort of sequencing/threading problem in the underlying backtester results display code.

Honestly was very excited to use QuantConnect but feeling very deflated at the minute, if we can't even get the backtester rock solid then it doesn't give me much hope.

Sorry that's happening. What you are both describing  doesn't actually happen to me. It could be the backtest node that I'm using, perhaps. Don't know.

I'm sure one of the staff should be able to step in and help, though.

You can also ask in the discord.

Good luck.

Thanks .ekz.. I'm using the free node currently as didn't want to pay for anything until I'm confident it'll work. 

Anyone from QuantConnect got any ideas? 

Will happily subscribe in future if the platform does what I need.

Hi John,

Please provide the following information:

• Number and resolution of subscriptions
• Date range
• Trade frequency
• Number of custom charts

If the algorithm creates a lot of data, when the algorithm tries to upload it to view, it can time out.

Best,
Derek Melchin

Want to invest in QuantConnect as we build the Linux of quant finance? Checkout our Wefunder campaign to join the revolution.

Hi Derek Melchin. I was only using 1 subscription, a Dow Jones Future. I was testing at minute resolution for timespans around 2-4 years and wasn't using any charts. Only approximately 30 orders a year, A very simple backtest to get myself familiar with QuantConnect. 

I'd expect to see some sort of error message when something times out but didn't see anything. 

As Nico previously mentioned, the “waiting for chart” error can be resolved by unchecking and rechecking the chart button.

Hi John,

If a backtest produces more than 700 MB of data, then Lean can't upload the results and the backtest results page appears empty. The algorithm above sounds like it doesn't exceed 700 MB of data. Please share the algorithm so we can reproduce the issue.

Best,
Derek Melchin

Want to invest in QuantConnect as we build the Linux of quant finance? Checkout our Wefunder campaign to join the revolution.

Derek Melchin Thank you Derek. I'm trying it tonight again and it's working flawlessly, typical :) I will let you know when I see this again.

I have had fairly consistent “Waiting for chart” messages. If you are patient “and click around”, some of them start to show up, but not all. I am hoping this is because I am not yet a paying custom and am getting low CPU priority. But, dare I buy-in only to find that the problem has not gone away?

Happened to me a few times. Usually, I was running a backtest with a short time frame so it ran very quickly. I suspect the comment above about not running backtest too quickly back to back may be on to something. 

Sorry its been flakey Bill! Its definitely slower with the free tier; and occasionally very short backtests take a few seconds to load up. If you're not happy after upgrading we'll refund or credit any expense to your account.

I upgraded to the paid tier. It's been okay for me so far thankfully. Would be good to try and get this fixed if possible Jared Broad. As a first impression it nearly put me off and I'd imagine it might do the same for others. 

I made this comment elsewhere…. If a run has finished, you can not leave visible charts that state they are waiting for data (that will never come) based on the type of analysis that was run. It gives a clear impression that the run is not over. Either remove all evidence of the unused charts or, perhaps, change the comment to: This chart was not used by the latest run.

Latest scenario. Ran a test. It started to draw bars in the Strategy Equity chart. Then apparently the test completed and now all chart windows are blank. Tried to copy/paste from the “cloud terminal” output tab (in case it contained any helpful diagnostics), but that does not work (even though the pop-up menu offers Copy). This all needs to be fixed. Off to eat turkey.

Ok. The work around is to press the browser “Reload this page” button and then reselect the analysis tab with the cheeky name. Excuse me if this has been observed and reported somewhere else.
Then all of the results, charts etc are filled. This was not expected. Needs to be fixed.

Thanks Bill. To keep forums focused on strategy development and appropriately file and track bug reports we ask they're submitted as support messages to support@quantconnect.com If you can send in a screenshot with the report it would be helpful.