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Former Member
Dec 18, 2009 at 04:50 PM

Access path calculation of CBO

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Hello,

I have installed ABAP Trial 7.01 with MaxDB 7.7.06.07 to make some tests with the Cost Based Optimizer of MaxDB. SAP uses host variables in the database interface and the access path of the CBO is calculated without knowledge about the actual values. IN standard SAP the access path is the same, regardless if one row or 1 Mio rows are selected. This behavior I saw in DB2 and Oracle, but for MaxDB it looks like the costvalue at the end depends on the number of read pages/rows. The costvalue depends on the values of the host variables.

Am I wrong or is the calculation of the access path in MaxDB depending on the actual values?

Regards Bernd