Users can improve analytical reporting performance by Avoiding Slow Fields in Reports.
Slow fields are fields that include large amounts of data and, when added to a report, cause the report query to take a long time to run or even time out.
Ariba Spend Analysis dynamically determines which fields are slow based on the current view of data in a report. By default, slow fields are disabled.
To enable or disable slow fields in reports.
1 On the Ariba Spend Management command bar, click Preferences and choose Change reporting preferences.
2 Click the Add slow fields to reports without restrictions and view hidden fields check box.
3 Click OK. Log out and log back in to apply the changes to your reporting preferences.
Hope this will help users.
There are so many factors in Analysis report which may leads to perform issue.
Try to run same report by setting Manage-> Change Reporting Preferences- Set it to Data load scheme and observe time taken for displaying report.
Try to run same report by setting Manage-> Change Reporting Preferences- UnCheck the Data load scheme Option and observe time taken for displaying report.
I suspect you might be running your report whenever data load is happening in your system and who ever the users has limited permission to run reports based data load schema( at time of data load is happening) then there may be chance of slow performance.
Please note only few user will be given access to run the reports in both Data and Presentation Schema.
Hope this may help you to some extended.