Unloading the rarely used column tables on to the persistent layer ?

[Former Member]

Hello Folks,

Can someone please let me know how to unload the column tables of a particular schema that are not being used every now and then, on to the persistent layer?

eg: UNLOAD "SCHEMA_NAME"."TABLE_NAME" will unload only a particular table on to the disk, but how do i select the tables that were inactive say since the last 1 week of a particular schema.

Thanks in advance.

Regards,

Krishna

[AtulKumarJain · Accepted solution]

Hi Krishana,

Please check

How to selectively unload/load data from RAM | SAP HANA

BR

Atul

[Former Member · Accepted solution]

Hi Atul,

Thank you for providing me with the information,As per the link you sent me i am assuming that the process of unloading the rarely used inactive tables on to the DISK is totally managed by the HANA's inbuilt algorithm. But HANA only unloads the tables on to the persistent layer when the memory reaches to or above 90% of the memory, There should be a way out .

BTW its krishna and not  Krishana

Regards,

Krishna

[lbreddemann · Accepted solution]

What is the advantage you see in manually unloading tables/columns when there still is memory available?

What do you get out of this additional (and actually high effort) action?

[former_member182302]

Hi Krishna,

Have a look on this:

Regards,

Krishna Tangudu

[Former Member]

Hi Krishna,

Thanku for suggesting me to look into this document it is really helpful, But unfortunately the document says that hana is going to load the tables which were least recently used into the persistent layer only when it hits 95% of the memory. I was wondering if i can manually unload the tables which are not in use to the persistent layer?

Regards,

Krishna.

[former_member182302]

You can use UNLOAD

Regards,

Krishna Tangudu

[Former Member]

Well yeah,

UNLOAD "SCHEMA_NAME"."TABLE_NAME";

is only going to unload a single table, but my scenario here is to unload many tables from a particular schema which were not being used since quiet some time in one go.

Can you please help me to write a procedure to perform the desired task?

Regards,

Krishna.

[Former Member]

If LAST_REPLAY_LOG_TIME was the last time the table log was replayed,I could manage to write a query and fetch all the inactive tables (1 single column with 150 records each record is a "table_name") since quiet some time and now i want to append it dynamically to "unload" and run a procedure where {unlaod table1;},{unload table2;},{unload table3;}.......and so onnn  should run for 150 times in a loop, I just want to know how the procedure is supposed to be.

Regards,

Krishna

[former_member182302]

Hi Krishna,

You may want to have a look on LAST_ACCESS_TIME column from M_CS_COLUMNS table.

Regards,

Krishna Tangudu