SSRS 2017 -- Why does a cached report render interactively instead of from a pre-generated snapshot?

Question

Hi All,

I am seeing strange behavior with cached reports. I have configured a report to always render from pre-generated snapshots. As a result, from the user's viewpoint, the report renders almost instantaneously.

But sometimes, the report renders interactively. When this happens it takes a long time, frustrating the user. Why is this happening?

My report is configured as follows:

When I look at the snippet below, from ExecutionLog3, this is what I see:

TimeStart	Source	Status	ByteCount  
2020-09-23 10:54:59.490	Snapshot	rsSuccess	3401  
2020-09-23 08:59:47.067	Snapshot	rsSuccess	3401  
2020-09-23 08:40:35.963	Snapshot	rsSuccess	3423  
2020-09-23 08:39:33.930	Snapshot	rsSuccess	3423  
**2020-09-23 08:19:04.803	Session	rsSuccess	1113565**  
2020-09-23 08:14:58.497	Snapshot	rsSuccess	3423  
2020-09-23 07:53:01.493	Snapshot	rsSuccess	3423  
2020-09-22 07:54:31.813	Snapshot	rsSuccess	3423  
2020-09-21 08:40:52.123	Snapshot	rsSuccess	3423  
2020-09-21 07:57:38.287	Snapshot	rsSuccess	3423  
2020-09-19 19:59:31.387	Snapshot	rsSuccess	3423  
2020-09-18 07:58:35.273	Snapshot	rsSuccess	3423  
2020-09-18 07:51:27.583	Snapshot	rsSuccess	3423  
2020-09-18 07:37:06.007	Snapshot	rsSuccess	3423  
2020-09-17 09:58:13.430	Snapshot	rsSuccess	3423  
2020-09-17 07:56:02.873	Snapshot	rsSuccess	3423  
2020-09-16 07:35:06.003	Snapshot	rsSuccess	3423  
2020-09-16 07:26:45.480	Snapshot	rsSuccess	3423  
2020-09-15 14:14:35.003	Snapshot	rsSuccess	3423  
2020-09-15 13:35:01.650	Snapshot	rsSuccess	3423  

Why is one of my executions running as a "Session" rather than as a "Snapshot"?

Thank you,

--Dan

Answer 1

Hi @DJAdan ,

In excutionlog3, session indicates a follow up request within an already established session. For example the initial request is to view page 1, and the follow up request is to export to Excel with the current session state.

You may check the format on the session line to see what action has been done. I assume the session isn't related with the snapshot.

https://learn.microsoft.com/en-us/sql/reporting-services/report-server/report-server-executionlog-and-the-executionlog3-view?view=sql-server-ver15

But sometimes, the report renders interactively. When this happens it takes a long time, frustrating the user.

Do you mean that when the users run the report which has been cached, it takes long time to render? If yes, you may record the time and go to the ecutionlog3 for further analysis. If I misunderstand your meaning, please incorrect me.

Regards,

Zoe

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Answer 2

Thank you Zoe.

I think you are correct. Further analysis of the ExecutionLog3 reveals that the user tried to export the report to PDF and PPTX. The report executionid was the same for all executions. The "Session" shown above in my example was a PDF export, from a report that rendered via the Snapshot first.

I also think the user is experiencing significant download latency due to "working-from-home". The report renders quickly, but downloading takes time over home wifi connections. THis is just conjecture of course.

Thank you once again,

--Dan