what is the significant and technical difference for DSO in Hana and non hana RDBMS

[Former Member]

Hi,

Could you please give me clarity on what is the significant and technical difference between DSO in BW on Hana DB and DSO on non-hana RDBMS DB?

Because, I often gets confused and couldn't get any significant difference although I read the following document:

http://help.sap.com/saphelp_nw73ehp1/helpdata/en/32/5e81c7f25e44abb6053251c0c763f7/frameset.htm

We migrated BW on Oracle RDBMS system to Hana DB System(Netweaver 7.30) and we have SP 9.

We had recently converted certain DSO's from Hana optimized to standard optimized DSO using the conversion program given in the above link.  We faced some issues during such conversion and implemented correction notes which made DSO's to be converted to standard optimized DSO's.

Though SAP Note 1849497/98 suggests such explanation on hana optimized DSO's, I would like to understand how does such hana optimized DSO's behaves in Hana and other RDBMS(eg: oracle)system regarding it's activation table, changelog and activation queue table.; regarding it's behavior, performance etc.;

Kindly suggest.

Regards,

Antony Jerald.

[Former Member · Accepted solution]

Hi Antony,

Please note the following points:

• Standard DSO before SP8 is similar to DSO running on any other Non-HANA DB.  So, optimization was required to convert the underlying table structure, viz., calculation view based change-log, history index etc.,
• Standard (Optimized) DSO from SP8 onwards has the following optimizations:
  • Persistent Changelog with no additional memory requirement as in case of calculation view based changelog
  • No need for history index (one of the components of active table)
  • Non-active data concept.

In the nutshell, the method of optimization has changed between IMO DSO (before SP8) and IMO(standard) DSO (starting SP8).

There is some minor correction to your understanding, "Both are calculating changelog data from calculation view."  One is calculating from calculation view and other from persistent table.

Hope things are clear.

Regards.

[Former Member · Accepted solution]

Hi,

You mean to say IMO Dso performs calculation for Changelog from Calculation view and Standard Optimized DSO from Persistent table in hana?

What does persistent table contains and what are persistent tables?

Could you please give me some points?

Regards,

Antony Jerald.

[Former Member · Accepted solution]

Persistent table referred here is the changelog table.  Persistent tables contain physical data unlike views.

[maryshilpa_balavendra · Accepted solution]

Hi Karthik,

All standard DSOs now automaticllay have the HANA optimized activation.

So there is no separate provider called the HANA optimized DSO from 7.3 SP10 onwards.

Please check the document: http://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/600163da-ae9a-3010-2f8c-8d06f33c0...

You do not have to execute any conversion for DSOs and all 3 tables work in the same manner as Standard DSOs. The big difference is that the activation process is executed at the HANA level via stored procedure (pushed down) instead of the ABAP layer .

Thanks and Regards,

Shilpa

[Former Member]

Hi,

Is there anyone to reply back to my query?  Plz kindly suggest.

Regards,

Antony Jerald.

[Former Member]

Hi,

Have a look at the below presentation, especially slides 14 to 20.

http://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/50066704-4173-2f10-4cb4-af3462161...

Regards.

[Former Member]

Hi Karthik,

Thanks a lot for sharing document with me.  It was really useful 🙂

However, I would be much happy if I get more elaboration on the points which had mentioned in the presentation document.

Could you please elaborate on those points on Hana optimized DSO's in BW on Hana ?

Also, we recently converted many hana optimized DSO's to standard optimized DSO's according to SAP Note: 1849497/98, in BW on Hana, which suggests Hana optimized DSO's are obsolete and standard optimized DSO's itself can be hana optimized DSO's with more performance improvement features.

Wanted to understand more detailed on this.

Regards,

Antony Jerald.

[Gabor_Kovacs]

Hi Antony,

According to the referred SAP note you do not need to worry about converting DSOs any longer in order to take advantage of the SAP HANA DB - that is the data load request activation is executed via a stored procedure in the HANA DB ("pushed down to HANA").

For the technical details you can check the 'Correction instructions' in the SAP note 1849497 and the code details for CL_RSODSO_ACTIVATE* classes and methods.

Prior this change the conversion to HANA-optimized DSO also changes the persistent change log table to a calculation view, so the change log records have been calculated on the fly whenever it has been needed - e.g. if the DSO is a source to multiple targets (like InfoCubes) the change log has been calculated each time loading from this DSO to a target. In some cases additional optimization could be considered: see SAP note: 1762935 - HANADB: Using the compressed change log (delta)

After SAP note 1849497 there is no need (or not even possible) to execute this conversion for DSO objects and DSO-based SPOs. Instead, the change log remains persistent table (just like BW on other RDBMS before the migration to HANA), or can be re-converted based on SAP note 1849498. The activation still takes place via stored procedure providing faster processing.

Otherwise the DSO tables have the same purpose as before.

Regards,

Gabor

[Former Member]

Hi,

Thanks for your reply!!

While initially we had SP6 for Hana DB, what ever DSO we create, it's Hana optimized DSO, we could find hana optimized flag in any DSO(from display DSO settings).

After upgrading Hana to SP9, for Netweaver 7.3, we still had Hana optimized DSO and for any new DSO's we create, after implementing notes 1849497/98, it's not the hana optimized DSO rather, it's a standard optimized DSO and this itself optimized for In memory.  As SP9 doesn't provide options to create hana optimized DSO's.  As sap note 1849497/98 suggests conversion of hana optimized DSO to standard DSO through conversion program given there.

We had faced problem at that time and following are those because of Hana optimized DSO:

>>Zero delta records are pulled from source DSO(IMO DSO) to target DSO(this is because, changelog tables were not pointing to calculation view, followed OSS message, through conversion program, we corrected this problem)

>>Unable to do filters in DTP on non-key fields for data in the IMO DSO which is archived to NLS

For the above two cases, we are suggested to convert IMO DSO to standard DSO or upgrade SP10/Use Netweaver 7.4

We don't want to upgrade our SP/netweaver so we followed SAP Note 1849497/98 and converted all such IMO DSO's to standard optimized DSO's, as standard optimized DSO are itself a hana optimized DSOs 🙂

So who ever doesn't have BW on hana for Netweaver 7.4/SP 10 for Netweavver 7.3, they can implement notes and convert IMO DSO's to standard Optimized DSO's

Shared based on what I had experienced in last 6 months.  Correct me if I'm technically wrong

Will surely write a blog/document on this on what I had experienced and learned.

Had little doubts between IMO DSO Vs Standard Optimized DSO's quite clear from Karthik T share.  But Wanted to know more detail about that.  Which often confuses me why is the need for Standard DSO instead of IMO DSO, bcoz, Standard optimized DSO itself hana optimized DSO, then why we are moving to Standard DSO from IMO DSO? Both are calculating changelog data from calculation view.  Is it differs only bcoz of performance?

Regards,

Antony Jerald.

[sunny_pahuja2]

Hello,

Please refer to below link which will give you some insight:

http://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/600163da-ae9a-3010-2f8c-8d06f33c0...

Thanks,

Sunny

[Former Member]

Hi,

I had seen this link when it's released initially.  But, here it jst reveals points and it couldn't explain much especially about changelog data and it's storage at table with calculation view aspect.

I would like to know how this differs with  non hana RDBMS based BW and much detailed learning and understanding about operation to all it's tables in BW on hana for any DSO regarding it's changelog table, active and activation queue tables.

Kindly suggest and clarify for my understanding.

Regards,

Antony Jerald.