Diagnosis
No buffer statistic history can be found in the database. The reasoncan be, that the history collector job COLLECTOR_FOR_PERFORMANCEMONITORis not scheduled every hour.

Procedure
Schedule the background job COLLECTOR_FOR_PERFORMANCEMONITOR (executingthe report RSCOLL00) hourly and make sure that the report RSTUNE80 iscontained in table TCOLL.