How to free up memory in HANA? Is it possible to unload Table from memory?
Yes, it is possible. SAP HANA Appliance can be used in smarter way to achieve maximum out of it.
In a typical business scenario, one SAP HANA appliance is used for DEV, TRN, TST environments. So, definitely there will be a major issue in this case – How to handle memory as memory is limited in that particular HANA appliance?
Under normal circumstances, the SAP HANA database manages the loading and unloading of tables into and from memory independently. Actually, the main aim of SAP HANA database is to keep all relevant data in memory.
But, one can manually load and unload individual tables if necessary. How?….It’s simple, and it can be done from SAP HANA Studio itself.
Select the table by right click and choose the option “Unload …”
And later, manually load the table into memory again, if needed.
Moreover, if somebody fires the query associated to the same unloaded table, SAP HANA will pick & load the same table into memory FULL or PARTIALLY, purely depending upon the executed query.
Again, if one needs to free up memory, he/she can manually trigger the delta merge operation for a column table manually in SAP HANA Studio. The delta merge operation is related to the memory management concept of the column store, i.e, the part of the SAP HANA Database that manages data organized in columns in memory.
So, options are as follows:
“Unload …” – Free up memory by unloading table from memory
“Load …” – Loading the table into memory
“Merge…” – Triggering delta merge operation for a column table
For more clear understanding(with screenshots), visit : http://debajitb.wix.com/debajitbanerjee/apps/blog/how-to-free-up-memory-in-hana