|
Blogs
Part 1 - Introduction and basic settings Full article also available in SDN's Article section here. Query LoggingOne of the most useful diagnostic tools is looking at what the OLAP Data Access component is asking the OLAP server for. If the OLAP server is Microsoft Analysis Services or other ODBO based data access and SAP BW/Netweaver BI then this is in the form of MDX queries. Is the data source is Essbase then this is in the form of report scripts. ODBO and SAPThe MDX executed by the ODBO and SAP data drivers, as well as being logged in the main log file, can be logged in a separate log file which just contains MDX queries. To enable MDX logging to a separate file an additional entry must be made in the registry. The additional entry is a string value with the name MDX Query Log. The contents of this string value are the path and name of a file to log the MDX to. The location of the key depends on the data source that MDX logging is required for. For logging MDX sent to an ODBO based OLAP server, the string value is located under ODBOMODULE folder. For logging MDX sent to an SAP BW OLAP server, the string value is located under the SAPMODULE folder. For example here is what the registry settings look like for an MDA 12 system:
Adding this to the registry will log MDX queries for ODBO data sources to a file ODBOMDX.log and MDX queries for SAP data sources to a file called SAPMDX.log. Both these files will be located in the following directory:
EssbaseAlthough it's not possible to log out the Essbase report scripts to a separate file it is possible to reduce the amount of logging in the main to the point where the Essbase report scripts are one the very few or only things logged out. The Essbases report scripts are logged under the DATASOURCE component under the ESSBASEMODULE module. There are logged out at verbosities of 4 (Info) and higher. The following is an example of the registry settings from an MDA 12 system that would log at this level.
Query TimingFor the MDX query logging there is an additional setting that can be added to log out the time a query took to execute. This can be turned on by adding an additional DWORD to the registry called MDX Query Clock. This is located in either the ODBOMODULE or SAPMODULE folders. A value of 1 will log the query times and a value of 0 will turn the query time logging off. Here is an example for a MDA 12 system.
This example registry setting has the query clock turned on for ODBO MDX logging and off for SAP MDX logging. Reuben Cox is in development support at SAP specializing in the NetWeaver web infrastructure components. He was formerly part of Business Objects specializing in OLAP products. |