Used memory in HANA - less/more/these same?

[Former Member]

Hi,

I've question for you guys. I've database in DB2 (50GB) which data I import using Data Services to HANA, I change table type to column type. And in HANA I still have 50GB database. Why does it happen? I know that my database in HANA will use less used memory than in another "row" database. It's correct?

Thanks for answer.

Regards,

Pawel

[Vitaliy-R]

Can you check if the data in your tables are in Main or in Delta part of the column-based table? Delta part is not fully size-optimized, as its purpose is fast writing.

You may need to run MERGE DELTA OF "SCHEMA"."TABLE";

The second thing is that final compression ratio depends on multiple factors: sparsity of the table, cardinality of rows, data types used.

Pozdrawiam,

-Vitaliy

[Former Member]

Hi!

Vitaliy, you're right about merging tables. After I've imported data to HANA I have only wait for "column" tables to merge themselves.

Thanks a lot for your answer!

Regards - pozdrawiam

Pawel

[Vitaliy-R]

Pawel, what is your compression ratio after merge has happened? Dzięki. -Vitaliy

[Former Member]

Hi Vitaliy!

My ratio is 4.5 (compressed data from DB2 to HANA).

Regards, pozdrawiam,

Pawel