Display Delta Merge Statistics of HANA Database using SAP HANA Studio
SAP HANA Studio Administration view for SAP HANA database system provides Delta Merge Statistics for database developers and HANA database administrators. These delta merge statistics provide useful information to understand a possible slowness of queries executed on a HANA database table. Especially after a heavy write workload on a table on HANA database, processing a delta merge will improve READ performance on that table.
Just to remember, column store provides read only access to HANA database tables. For write requests, row store is used on HANA database systems. Read performance is good with columnstore storage and Write performance is best with rowstore storage.
Periodically moving data in rowstore to columnstore storage will increase read performance. And on SAP HANA database this process is called Delta Merge
It is possible to review delta merge process status of a SAP HANA database using SAP HANA Studio.
When you switch to SAP HANA Development perspective on SAP HANA Studio and on Systems window connect to target SAP HANA database system.
Double click on the system name in Systems explorer window to launch Administration view.
You can right-click on system name and on context menu follow menu options Configuration and Monitoring > Open Administration
Under System Information tab you will see Merge Statistics when you drill down System node.
Double click on Merge Statistics line to display merge statistics for that SAP HANA database like merged database tables, merge start date and time, execution duration and results like success or fail, error details or successfully merged number of rows, etc.
For example, I had converted AdventureWorksLT database tables from SQL Server into sample SAP HANA database tables.
It is good to see which table has been processed when for delta merge task and see if its motivation (Auto, Critical, Hard, Smart, Soft), result (success or fail), number of merged_delta_records, etc on a single page for all schemas and included tables of the SAP HANA database.