freeze after pats disconnect

[zweistein]

Hello,

this is a follow up of an older thread

http://www.ninjatrader.com/support/forum/showthread.php?t=34349&highlight=pats

unfortunately the problem is not resolved.
Problem is a freeze a NT7 due to a disconnection of the PATS connection.
As we are in a holiday period in these days it seems that disconnects are more frequent and it happened twice to me in the last 2 days.

Here to reproduce (-not always-)

Connect to IB and connect to your pats account.

Use firewall ore router or packet sniffer and change the firewall/blocking such that your pats connection gets disturbed and fails.
Wait 5 - 10 minutes.

Then exit NT7.
This will cause NT7 to freeze and you must kill the process to close it.


In less reproducible scenarios this will cause NT7 to freeze during normal working (using the IB connection as the pats connection is down)

Please try to reproduce.
You will have to dedicate several hours to find a way to reproduce

and then please fix.

regards
Andreas

[NinjaTrader_Bertrand]

Hi Andreas, thanks for the post and details included here, different team members have been chasing this one but so far we were unfortunately not able to clealy reproduce a case - that being said I've got this on my list to look into and reproduce, with the added details you posted it's hopefully eaasier to catch.

Thanks,

[NinjaTrader_Bertrand]

Andreas, I tried reproducing here today but so far I was not able to - when the PATS connection is fully lost and I wait through the potential reconnection period (that willingly fails) then I could not see NT7 freezing up here. I will keep it on my list though to keep an eye on, if you spot any missing detail please let me know.

[zweistein]

Thank you so far...

Are you on a multi-broker NT7?

My config is 2 IB accounts and a 3rd pats account.

Is your pfgbest adapter better ? I am considering switching to that broker instead of Pats

andreas

[NinjaTrader_Bertrand]

Yes, I'm testing on a MultiBroker setup here, too - I could unfortunately not recommend you a specific technology to use, we have many valuable partners...

[zweistein]

Let us remember the facts:

1. Error difficult to reproduce ( I have tried many times to nail down the error scenario)
2. No error message in the log
3. plain freeze of NT
4. happens during reconnect after a connection error

In my view this is a typical case a a multithreading deadlock.
for example: IB adapter attempts to reconnect but it is waiting for the Patsadapter to release resources, butPatsadapter has locked its resources because it also started reconnect. Same is true for Patsadapter which is waiting: for IBadapter .
Result a deadlock:

Unfortunately I don't know your internal threading policy, so above scenario must be checked by someone with deep knowledge of NT7.

I would investigate the details of the reconnecting thread logic, maybe it is just sufficient to add a simple mutex...

regards
andreas

[NinjaTrader_Bertrand]

Andreas, thanks for the details and your testing, eventhough so far I've not been able to reproduce it cleanly here I'll forward your findings to our developers so they could review them.

[zweistein]

problem still around and not solved.

Here another test scenario:

Use multiple connections, IB 1, IB 2 and Pats.
Wait for Pats connection error (or generate yourself by tcp port blocking)

Then with pats connection in the orange state close NinjaTrader with save workspace option. NinjaTrader will not close and freeze instead.


regards
andreas

[NinjaTrader_Bertrand]

Hello Andreas, thanks again for providing those scenarios to us - after our analysis you unfortunately run into a current limitation here : we've added those cases to our list to look into and track them under # 855 now.