Visualizations intermittently fail to load

[greenawayr]

Hi,

We're experiencing an issue with PowerBI Report Server (Jan 19). In particular one report, where, if I save the report from PBI Desktop to the report server, and then open up the report from report server, the report loads fine. However, if opening the report up after a scheduled refresh, some of the visualizations will fail to load. If I allow the visualizations to error, and then CTRL+F5 then they tend to load ok the second time, but this is not acceptable for our users obviously.

I'm presuming it's some sort of timeout, but it'll be different visualizations failing each time.

The data is  being queried from a few SharePoint (on prem) lists.

The scheduled refresh itself, doesn't take long to run. I don't really want to extend the timeout as it already takes 20 seconds or before the visuals fail, shouldn't have to wait that long for a dashboard to load. We have other dashboards that have more data in  that load fine. 

One other thought is that this dashboard has a scheduled refresh for every 10 minutes, whereas our other dashboards refresh hourly. Could this have an impact?

Thanks  

[ITGeek555]

Hi greenawayr,

1. Are you seeing any errors in the PBIRS logs?
2. When you ctrl+F5 the refreshed report with the failed visuals, does the report show updated data (indicating that the refresh succeeded)
3. Are the visualizations that fail custom visuals? If so, change them for visuals that come with PBI desktop and see if the issue remains. If the issue goes away it may be that the custom visuals have an issue.

[greenawayr]

Thanks for the reply.

1. Here are the errors I appear to be getting in the logs

2019-05-17 09:45:42.6240|INFO|42|Sending response. Response code Domain\loginname 500, Elapsed time 0:00:01.3707313| RequestID = 9280c85f-b127-343d-ef60-32909af51001 ClientSessionID = 2ada3353-ae02-1703-5fe2-a6ce677b484f
2019-05-17 09:45:58.7011|INFO|36|Received request POST /api/explore/reports/5d568d16-57bd-40a1-a115-7f1368843a7b/querydata| RequestID = 134c059b-921f-d3dc-4760-b93df4b83d5e ClientSessionID = 2ada3353-ae02-1703-5fe2-a6ce677b484f
2019-05-17 09:45:58.8104|ERROR|40|Failed to get connection string for model | RequestID = 134c059b-921f-d3dc-4760-b93df4b83d5e ClientSessionID = 2ada3353-ae02-1703-5fe2-a6ce677b484f Microsoft.PowerBI.ReportServer.AsServer.AsConnectionException: Failed to get connection string for model
2019-05-17 09:45:58.8104|ERROR|47|GetDataSource ERROR for catalogItem=5d568d16-57bd-40a1-a115-7f1368843a7b, Exception=Failed to get connection string for model , ElapsedMs=110| RequestID = 134c059b-921f-d3dc-4760-b93df4b83d5e ClientSessionID = 2ada3353-ae02-1703-5fe2-a6ce677b484f
2019-05-17 09:45:58.8104|INFO|46|Attempting to re-stream the model 5d568d16-57bd-40a1-a115-7f1368843a7b for request 134c059b-921f-d3dc-4760-b93df4b83d5e, session 2ada3353-ae02-1703-5fe2-a6ce677b484f| RequestID = 134c059b-921f-d3dc-4760-b93df4b83d5e ClientSessionID = 2ada3353-ae02-1703-5fe2-a6ce677b484f
2019-05-17 09:45:59.9354|ERROR|28|Failed to get connection string for model | RequestID = 134c059b-921f-d3dc-4760-b93df4b83d5e ClientSessionID = 2ada3353-ae02-1703-5fe2-a6ce677b484f Microsoft.PowerBI.ReportServer.AsServer.AsConnectionException: Failed to get connection string for model
2019-05-17 09:45:59.9354|ERROR|56|GetDataSource ERROR for catalogItem=5d568d16-57bd-40a1-a115-7f1368843a7b, Exception=Failed to get connection string for model , ElapsedMs=102| RequestID = 134c059b-921f-d3dc-4760-b93df4b83d5e ClientSessionID = 2ada3353-ae02-1703-5fe2-a6ce677b484f
2019-05-17 09:45:59.9354|ERROR|7|Failure in querydata| RequestID = 134c059b-921f-d3dc-4760-b93df4b83d5e ClientSessionID = 2ada3353-ae02-1703-5fe2-a6ce677b484f Microsoft.PowerBI.ReportServer.AsServer.AsConnectionException: Failed to get connection string for model

Not sure quite what this is about as the connection string is fine and works for all other reports.

2. The data is updating and the scheduled refresh is completing without error.

3. There are no custom visuals. As I mentioned before, there's no consistency as to what visuals fail, changes with each load.

[greenawayr]

Additional information.

We have 2 Report Servers accessed by users through a load balancer.

When I logged on to the server direct and accessed the report using the server name and not the load balanced URL, the report loads fine.

Again, we're not seeing this problem with any other reports, at least, it's not been reported as such.

Would the number of visuals on a report be a possible cause? there are 30 visuals on this dashboard spread across 4 pages.

[greenawayr]

We have isolated the issue to our Load Balancer (Netscaler).

Removing one of the nodes considerably imrpoved the performance of the reports and all visuals loaded successfully.

This is obviously not an ideal solution and we would like to continue to run a scaled out deployment, so if anyone has suggestions as to why using the netscaler would cause this problem and performance degradation, I'd be grateful.

[ITGeek555]

We use netscaler as well. I have it configure with sticky sessions so a given user session is routed to the same server until the session ends. If your netscaler is randomly throwing requests between the two PBIRS servers it may explain your issue. 

[Rastenberger]

We have similar problems. How is your sticky sessions configured?  Is it cookie persistence-profile? There are different flavours of it.