to OLAP or not to OLAP

I want to ask what are the performance gains of pulling reports in Sharepoint 2010 directly from an Oracle DW using an ODBC Connection as opposed to building an OLAP Layer using SSAS and accessing th开发者_高级运维e data that way.

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It sounds like you're confusing terminologies and technologies. Comparing ODBC to OLAP and SSAS is like comparing apples to oranges. They are very different things used for very different purposes. The commonality is that they both deal with data... and apples and oranges are both fruit.

But, trying to read between the lines, OLAP, if configured correctly, will deliver actionable information (biz intel etc.) much more quickly and readily than data aggregated from a standard RDBMS. After all, that's what OLAP is designed for:

In computing, online analytical processing, or OLAP (play /ˈoʊlæp/), is an approach to swiftly answer multi-dimensional analytical (MDA) queries.1 OLAP is part of the broader category of business intelligence, which also encompasses relational reporting and data mining.[2]

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Now that SQL Server 2012 is released, you may want to look into building a BISM (using SSAS) over your Oracle data and then displaying the results in SharePoint.

Although you can use the 'PowerPivot on SharePoint' mode to be able to host (render) the BISM using SharePoint resources, you'd rather get a separate server to host SSAS, so that effort of rendering (presumably) large reports doesn't slow down your SharePoint server.

Of course it is still possible build an OLAP cube using SSAS, but unless you need one or more of the features not yet available in the BISM model, you'd rather just build a BISM than an OLAP cube, as the BISM leverages Vertipaq (so it's simpler to build, i.e. requires less ETL from Oracle). For more check out my deck on slideshare on the BISM