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change log data

Former Member
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Hi Experts

I have a question on Change log table in ODS. When i execute a query on the ods, From where the OLAP Processor

get the data for the changed records....

1. Do i get the data from active table?

2. Do i get the data from change log table?

Regards

Annie

Accepted Solutions (1)

Accepted Solutions (1)

Former Member
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hi,

its active table only.

Every ODS objects is represented on the data base by 3 transparent tables.

1.Active data table : It is a table containing the active data .

2.Activation quene tube It is used for saving ODS data records that are to be updated but that have not have been activated. But the data is deleted after the records have been activated.

3. Change log table :

It is used for updating delta from the ODS objects into other data targets such as ODS objects (or) info cubes.

REegards,

Manoseelan

Former Member
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Hello gurus

Thanks to everyone. sorry for getting back late...Generally when the change log data will be deleted...in real time how long do they retain in the change log table?

REgards

Annie

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hi Annie,

welcome back

it's depend on requirement, if you are sure that historical data (perhaps 2-3 years ago) won't never change anymore then you can do selective deletion for that time frame. hope this helps.

Former Member
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Hi AHP

Thanks for the reply..You reach faster then light

As we delete PSA data once in 10days does anyone in real time delete the changelog data once in a month. Like as you told if that data is no longer going to be changed we can delete.

REgards

Annie

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hi Annie,

i think you are faster

hmm in practice it seems 'too fast' in a month, deleting psa has no effect to ods data delta (you will need psa to reconstruction), but change log 'helps' in handling data changes, normally data will still being change in a month, some even a year or more

hope this helps.

Answers (4)

Answers (4)

former_member619464
Active Contributor
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Former Member
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Hi,

For reports u will get the data from Active tables and if the ODS is feeding another ODS or Cube it will go from Change log table.

Hope this helps.

Rgds,

Ravindra.

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hi Annie,

bw query get data (last value) from active table.

Former Member
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The active one !

(In fact, it's enough to consider that on the active data table - and not the change log one - you can build index to gain in performance....) and to activate BEx reporting !

Bye,

Roberto