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The HANA delta merge made visible

Posted: Tue Apr 30, 2013 11:17 am
by 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
DeltaMerge01.jpg (79.41 KiB) Viewed 23868 times
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
DeltaMerge02.jpg (79.48 KiB) Viewed 23868 times
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
DeltaMerge.png (43.99 KiB) Viewed 23697 times