Tuesday, 12 September 2017

General information about Data Aging

Many people heard about data aging in context of HANA. You see it on a lot of SAP slides with DLM (Data Lifecycle Management) or in BoH / S/4HANA context, books about HANA and especially in the result of the HANA ABAP sizing reports. In my opinion the naming here – “clean-up” – is a little bit  misleading. It is a bit more than just housekeeping and lot of things you have to pay attention to.

The sizing report uses by default a threshold of 15 days. All older data will be placed in the cold store and handled as historical data. This should be adjusted to your business data and in most cases 30 days and more will be used. As result you will get another sizing.



Prerequisites


1. The SAP application must provide Data Aging Objects
2. The Profile Parameter abap/data_aging is set to ‘on’
3. The Data Aging business function (DAAG_DATA_AGING) is switched on
4. Relevant authorizations for Data Aging activities are provided

SAP Application Techn. Data Aging Object Availability
Application Log (BC-SRV-BAL) BC_SBAL 7.40 SPS8
ALE Integration Technology (BC-MID-ALE) BC_IDOC 7.40 SPS8
G/L Accounting (FI-GL) in Smart Financials 1.0 FI_DOCUMENT Simple Finance add-on 1.0
Workflow (BC-BMT-WFM-RUN) BC_WORKITEM 7.40 SPS12
Change Document (BC-SRV-ASF-CHD) BC_CHDO 7.40 SPS12
Sales Documents SD_VBAK S/4 1610
Material Documents MM_MATDOC S/4 1511
Deliveries LE_LIKP S/4 1610
billing documents SD_VBRK S/4 1610
Purchase Orders MM_EKKO S/4 1610

Sizing


SAP HANA Tutorials and Certifications, SAP HANA Materials, SAP HANA Guides

Check under the first section of the sizing report if you benefit from data aging. You can see the benefit under the description ‘data clean-up’. But this is the sum of all data aging objects. May be you only want activate a specific one and want to know which table is it worth. Go to the clean-up details for the exact classification.

SAP HANA Tutorials and Certifications, SAP HANA Materials, SAP HANA Guides

SAP HANA Tutorials and Certifications, SAP HANA Materials, SAP HANA Guides

For the most ERP systems you will see that the biggest benefit can be achived in the change document area with aging object BC_CHDO. This affects table CDPOS and CDHDR. In this example you will save 5.3GB with 15 days retention. This means you also save 5.3GB working space. In sum you ~10.6GB memory footprint. In this case I would recommend not to use data aging, because the effort to activate it and adopt the custom code may be too high.

Transactions


Transaction Description
DAGOBJ Display all Data Aging Objects
DAGPTC Customizing for Partitioning
DAGPTM Manage Partitioning
DAGRUN Overview of Data Aging Runs
DAGADM Managing Data Aging Objects
DAGLOG Data Aging Log

Checklist

  • use sizing report to estimate your benefits
  • compare different sizing runs with report /SDF/READ_HDB_SIZING_RESULTS_2
  • check if you have Z-Coding which are using the aged tables => use the classes CL_ABAP_SESSION_TEMPERATURE and CL_ABAP_STACK_TEMPERATURE for access to cold data
  • check HANA parameters for cold data
  • check sizing of data volume
  • begin on high level with partitioning year > month > week because you can go to low level but not vice versa
  • keep checking your data aging runs