SAP HANA Dynamic Tiering on Disk or In-Memory

[former_member206016]

Hi Experts,

I am trying to understand when dynamic tiering generate Pview (Union of Hot-To-Cold), So when I do Select * From Pview where the query will run will it be on Disk or In-Memory?

[muthuram_shanmugavel2]

Hi Santhosh,

In Dynamic Tiering, HOT data is stored in In-memory and will be processed in In-memory itself.

[In-memory Tables - algorithms used to access the data are optimized for in-memory data].

In Dynamic Tiering, Cold data is stored in Extended storage [SAP IQ DB] and  will be processed in disk. [Extended Tables - algorithms used to access the data are optimized for disk-based data].

So for your scenario, while retrieving the data from PView,

Dynamic Tiering HOT data will be processed in HANA In-memory and

Dynamic Tiering COLD data will be processed in SAP IQ DB disk.

Regards,

Muthuram

[former_member206016]

Hi Muthuram,

Thanks for the clarification above.

But I am facing an issue here when the cold data record get updated in the source that record must ideally get change in the cold table but the cold record is showing as new records in Hot table, so by this scenario when you see the data in Pview you will have 2 records for the changed data.

Note: My source is ECC and provisioning is happing via SLT.

[muthuram_shanmugavel2]

Hi Santhosh,

I understand the Issue faced.

Can you please check the following things and let me know the results.

1. Create Columnar Table (T_Inmemory) with 2 Columns - ID & Name and

    Make it Column - ID as Primary Key.

2. Insert Data to the Table ranging 1 to 10.

3. Create Extended Storage Table (T_Extended) with same structure

4. Move all the records from In-Memory Table to Extended Table.

5. Now Insert record (1, Mr.A) Columnar Table (T_Inmemory).

If this record is Inserted, We will have two record for Employee ID - 1.

In this case, Please raise Message and contact SAP support for help.

We can do this as a workaround solution. 

Deleting the record (Employee ID - 1) from Extended Storage.

Regards,

Muthuram