The HANA delta merge made visible

[Hay Bouten]

During my classes I often get the question "Can I see the Delta Merge?". The answer is "Yes". Below I have taken a screenshot from the "SHOP_FACTS" before and after a delta merge.

Looking at the table definition => Runtime Information I see that the table size is 12.8MB and contains it contains 88553 records.

DeltaMerge01.jpg

After a delta merge the table size is 4.5MB and contains it still contains 88553 records. Also the compression due to storing the data in a columnar table is nicely visible.

DeltaMerge02.jpg

Forced a delta merge with this sql statement:

Code: Select all

MERGE DELTA OF "EFASHION"."SHOP_FACTS";

Or use the SAP HANA Studio.

DeltaMerge.png