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Index

Former Member
0 Kudos

Hi All

Can anybody give a idea about index.

1. Can we create index for ODS?

2. How can we check if any indexes created.

3. How does it help in improving performance in uploading the large data?

etc etc...

Thanks,

Rohini

Accepted Solutions (1)

Accepted Solutions (1)

Ashwin
Active Contributor
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hi!

here is some more information

Q1) can we create indexes on ods?

yes and here is the procedure. click "change" on context menü for ods object. and Under Indexes, you can create secondary indexes by using the context menu in order to improve the load and query performance of the ODS object. Primary indexes are created automatically by the system.

If the values in the index fields uniquely identify each record in the table, select Unique Index from the dialog box. The description of the indexes is specified by the system. To create a folder for the indexes, choose Continue from the dialog box. Now you can transfer the required key fields into the index folder using Drag&Drop.

You can create a maximum of 16 secondary indexes. These are also transported automatically.

more info on indexes can be found in the following link. http://help.sap.com/saphelp_erp2004/helpdata/en/cf/21eb20446011d189700000e8322d00/frameset.htm

Q2) you can see all the indexes created under this node.I think there is a posibility to use folders to organize the indexes.

with regards

ashwin.

Q3) is answered in the above post.

Former Member
0 Kudos

Hi Ashwin

Thanks

In your first reply you say index doesnt improve performance in the load and in the next post u say it improves the load. Can you clear little more on this.

Regards,

Rohini

Former Member
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Hi Rohini,

I think what Ashwin meant is:

additional indexes improves reading performance (queries) but will slowdown the loading processes (updating the ods takes some more time because of the overhead for maintaining the additional indexes).

regards

Siggi

Former Member
0 Kudos

Additional indexes on ODS-objects will cost performance when loading the ODS, but increase performance of reading data from the ODS (query or extraction to another InfoProvider), if the index was hit.

Ashwin
Active Contributor
0 Kudos

Hi rohini!

Siggi is right I meant exactly the same.

with regards

ashwin

Former Member
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Thanks Siggi, Mail, Ashwin

Then i understand that Index are not much usefull for improving upload performance, but helpfull for queries.Then in that case index are never used for upload? or is there any suitation where it is required.

Regards,

Rohini

Former Member
0 Kudos

Hi Rohini,

no, there is really no situation where a index is required for upload. As I mentioned before: Updating tables with lots of indexes will take more time, because all the indexes needs to be actualized too.

Reading from such a table will be much faster if you are able to read it with the specified index fields.

regards

Siggi

Answers (4)

Answers (4)

Former Member
0 Kudos

Secondary indices can be very useful in improving query performance. But, surprisingly,not mentioned in this thread is the need to review the portfolio of queries that run against the ODS.

You need to consider the following:

How frequently are different queries running?

What characteristics are most frequently used for selection of data?

How selective the characteristics are?

Are certain combinations of characteristics frequently used for filtering?

Weighing the resource and space consumption of an extra index(s) versus improved query performance.

This really requires a good understanding of how the ODS is being queried and understanding of RDBMS. Sounds like your best bet would be to involve a DBA. Adding additional indices without understanding this information can waste a lot of server resources and disk space, and may result in indices that are not used or less effective than they could be.

Ashwin
Active Contributor
0 Kudos

Hi rohini!

I dont think creating indexes will help in improving performance while <b>uploading</b> data, more over it will cost performance while loading as explained by Maik. But it will help improving the read performance of ODS object.

with regards

ashwin

Former Member
0 Kudos

Additional indexes might increase the load from ODS to other InfoProviders, but will cost performance while loading to the ODS.

Former Member
0 Kudos

rohini,

yes you can create indices for your ODS, and yes you can check them too - right-click on your ODS object and select change. from there there is an option at the bottom of the treeview aptly named "indexes".

as to helping performance? well, you'll have to measure that yourself by tracing the loading to see if it uses the indexes, among other things.

ryan.