To avoid performance issues we recommend to use filters.
When creating new workbooks you have the option to create them based on filters.
To create filter, follow these simple steps:
Open the datasource of the Workbook under the "Details" option
Adjust the filter to see only the really neccessary issues (e.g. "Bugs only")
Save the filter
Refresh your Workbook (F5 or the Refresh button of your browser)
Next time you want to create a new workbook, you will be able to create one based on your previously created filter.