"Communication with client fails" error

[ohernan]

I'm getting this error message in the NT event log on the W2K server running CE 8.0. What is the cause of it? When it occurs, the report fails to come up in the browser. Any solutions to this? Thanks!

 

[Rooble]

Check that your Web Component Server is running and also all other server components.

-Rooble

 

[ohernan]

Thanks for your response Rooble. Here's more detailed info on this NT event log message:

Source: Crystal_cacheserver
Category: PageServer
Event ID: 35207

Communication with client fails. Continue with other requests

Everytime this occurs, all CE services are indeed running. From my experience w/ CE, their error messages don't really describe the cause of the problem and have sent me 99% of the time on wild goose chases. If this message is an exception, it would indicate to me some problem between CE and the client's browser trying to open a report. If that is the case, any way to prevent this? Thanks!

 

[rci]

We've seen this error in CE 8.0 and CE 8.5:

The cacheserver has lost communication with the pageserver. We've been working with CE to solve the problem. You can try to stop and restart the pageserver, but if your problem is the same as ours, the pageserver will hang in a "Stopping" state. To get around this, you either have to reboot the CE server or start up another page server. On our production CE server, we have several pageservers defined just waiting to be started manually as needed.

In our case, Crystal told us that the problem is related to long-running reports being Refreshed from the report viewer or using View (as opposed to Schedule) for long-running reports. Those two methods of running reports use the pageserver while Schedule uses the jobserver. The pageserver has problems with reports that run for more than a minute. In CE 8.5, you can give users schedule access without refresh access.

Keith

 

[ohernan]

This may indeed be our problem, as it does occur when trying to open a report based on a long running stored procedure. We're working on improving the overall performance of our server queries our reports are based on, which should improve the stability of CE. I have noticed CE has the most problems with long running reports. I guess our time for now will be better spent tuning our database server and queries. For the project I'm working on, our reports have to run on demand, so scheduled reports isn't an option.

Thanks,
-Oliver

 

[rci]

Even restricting them to Schedule only will still allow them to run the reports on demand. They can 'schedule' a report to run right now. The restriction will just prevent them from doing a Refresh from the viewer and it won't let them use the View command in CE.

Keith

 

[ohernan]

Keith,

I'm not too familiar with scheduled reports in CE, but is what you're suggesting available with CE 8.0, the version we're running? But anyway, the users are viewing the reports as Acrobat .pdf files, so they don't have the viewer refresh button available. Are you basically saying though that by running reports as "schedule", the request will be handled by the jobserver instead of the pageserver, which Crystal told you has a problem handling long running reports?

Thanks,
-Oliver

 

[rci]

Yes, CE 8.0 has the same basic scheduling options as CE 8.5. And running the reports through 'schedule' will use the jobserver, which is better equipped to handle long-running reports.

Keith

 

[rscero]

Does anyone know of a way to "schedule" an un-managed report? Most of our reports are not run from within CE but via a URL command. Several of them have queries that will take longer than 1 minute to run as users can be pulling data across multiple years. We've been expirencing this problem alot lately.

 

[ohernan]

Hi rscero,

I do not think you can schedule an unmanaged report. Since you would have to use the Crystal Enterprise "Management" Console to schedule the report, it would need to have the report within it's environment. In the management console, you have to first select a report that is published to Crystal Enterprise.
For my particular problem, I have not figured out how to schedule a report to run immediately as rci suggests with CE 8.0. The only options I see in the Recurrence tab for reports are Daily, Weekly, Monthly, and On Demand. I don't see how to setup a managed report to be scheduled to run "now". So instead, we've significantly improved the performance of our SQL queries and stored procedures so that they won't take as long to run.
Also, I've learned about a couple of options in CE that affect the occurrence of this error. This error is basically a symptom of CE timing out waiting for a report's result set to return from the database. The options are "Minutes Before an Idle Job is Closed" of the page server, and "Minutes Before an Idle Job is Closed" of the cache server. Setting these to higher values will force CE to wait longer for reports to run. The only problem though is with the option to the page server. It seems to me that the page server does not reuse existing database connections for running reports. It opens a new connection to the database for every report, even if they're connecting to the exact same server and database. So it keeps these connections open on the database for the number of minutes set in the option "Minutes Before an Idle Job is Closed". We use SQL Server on our project, and I don't like seeing all these open idle connections to the database from CE - that can't be a good thing.