I am getting Streambase LiveView session channel error. Anyone can help?

I am getting Streambase LiveView session channel error when access my application from the browser. I have also noticed that LiveView performance is degradign over the period if we don't restart the LiveView server.

Brief description about the application:

It's a Real-Time dashboad application and users will be using this 24/7. We are using Streambase 7.6.0 version and LiveView 2.1.0. The LiveView API is used to fetch the data from LiveView datamart.

Please let me know if anyone can help on this. 

2 Comments

Hi Mic Hussey,

Thank you very much for your response. Sorry for the late reply. We understand that the session channel error and LiveView performance degrading issues are occuring while number of Liveview connections are getting increased. We have noticed the performance is good upto 70 Liveview connections. After that we started getting 'Session channel doesnot exist' errors and performance is degrading. I have killded few old sessions and noticed the performance is better. I have killed all the 'Cancelled-Query' sessions.

We have also changed the default session time out value from 10 hours to 1 minute. This helped in clear the connections after users closed the dashboard. However, i am still seeing many cancel-query sessions when i check in LVSessions table from LiveView web console. I suspect that some of these cancel-query sessions are not clearing. May i know at what scenarios these cancel-query sessions will be created?

Thanks in advance.

Regards,

Kiran.

yourkiran2007 - Jul 04, 2016 - 2:17am

Can you post the text of the error here  - it might help us figure out more exactly what's going on.

If the performance is gradually degrading over time it's usually worth looking at the queries you are using. Ordering full tables using timestamps is inefficient (equivalent to a full table scan) whereas queries comparing to now() are optimised. (eg "WHERE timeField BETWEEN now() - hours(2) AND now()").

You should also consider upgrading to LDM 2.1.3/SB 7.6.3 there was an issue closed which sounds similar to what you describe (from the release notes)

CQS‑3573

If a client connection session to LiveView Server timed out when there were active queries (generally due to the browser being closed when a LiveView Web instance was active), an UnknownSessionException error showed in the server console, and the session state was not correctly released. This was fixed.

Mic Hussey - Jun 10, 2016 - 6:32am
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