Maybe you already heard about the SAP EarlyWatch Alert Workspace in the SAP ONE Support Launchpad. The workspace is the central landing page for the SAP EarlyWatch Alert service – it offers apps which give you a comprehensive overview on your system landscape regarding stability, configuration, hardware utilization and performance. As of November 5th, a new app is available in the SAP EarlyWatch Alert Workspace – the 2 Billion Record Limit monitors and forecasts the number of entries in SAP HANA tables.
The number of records in a table or partition in SAP HANA can’t exceed 2 billion (more precisely 2.147.483.648 – 2 to the power of 31). In case a table is approaching this limit, you have to take actions – you can solve this problem by table partitioning (SAP Note 2044468) or deletion of no longer required records.
Use this app to get an overview which tables are approaching the limit including a prediction when the limit is reached, broken down into a mean, best-case and worst-case scenario. By default, the forecast is based on all previous measurements. You can, however, restrict the measurements used for the forecast.
To start the app, click on the title area of the corresponding card, or one of the time limits displayed. These serve as a filter, just like the dropdown list box Time Range in the app itself: so only tables reaching the record limit in a certain time range according to the worst-case scenario are listed. It is obviously unknown when precisely this limit is reached in the future. Of the various possibilities, the worst-case scenario is an unfavorable, yet possible forecast – with a probability of 80% the limit is reached later.
After calling the app the critical tables of the managed SAP HANA databases are listed. These are the non-partitioned tables and partitions, which will probably reach the 2-billion-record-limit in the next 30 weeks. The historical data used for this prediction is based on the top 40 tables and top 40 partitions by number of entries.
By default, these tables are sorted by the date the limit will be reached in the worst-case scenario. Like in the other cross-system apps of the SAP EarlyWatch Alert service, you can use the global filter to restrict the data displayed to specific customers or systems.
Choose an entry from the list to know more about the record forecast of the corresponding table. The measurement points of the record numbers in their temporal evolution are displayed. For the possible future trend, you can see three different dashed curves:
- Forecast Low 80%: The actual measurements will be above this curve with a probability of 80%.
- Forecast Mean: Based on the considered measurements, this curve represents the most probable future trend.
- Forecast High 80%: The actual measurements will be below this curve with a probability of 80%. This curve represents the Prediction: Worst-Case Date in the list.
By default, all measurement points for the number of table records available in SAP EarlyWatch Alert are used for the forecast. If, however, some of the data points would disturb the calculation, e.g. because the boundary conditions during measurement time have changed, you can restrict the points used for the forecast. To do so, select the points in the diagram you want to use for the recalculation.
In the example above, the increase is largely uniform – except for the first measurement. Probably this was a unique effect, so I select only the subsequent measurements and choose Recalculation:
After the recalculation, these points are shown in orange – and you can see that the forecast is much more accurate:
When you choose this table the next time, all measurement points are used for the forecast again. To save the selection permanently, choose the icon Save Data Points.
Keep in mind that the forecast is based on the existing measurements only. Deviations from the forecast, e.g. by unforeseen events, are always possible. Therefore, reaching the technical limit may occur earlier in reality than predicted in the worst-case-scenario. So never rely on the prediction only, but remedy the situation as soon as possible.