Oracle, the last major OLAP vendor to embrace MDX, has finally added MDX support to its server. The MDX Provider for Oracle OLAP, developed in partnership with Simba, implements the OLE DB for OLAP API and the MDX query language, and went beta this week.
The most obvious application of this technology, and I'm sure the initial revenue driver, will be to allow end-users to use Excel 2007 as their client for slicing and dicing.
Simba's architecture diagram shows the MDX provider loaded onto the same machine as the Excel client. It wouldn't seem technically difficult to run the MDX provider as a server, and have multiple clients connect via OLE DB for OLAP or via XML for Analysis. (Licensing may be a different matter.)
This announcement means that now it is possible to talk MDX to every major OLAP server. (Are there any OLAP servers that do not speak MDX? I can't think of any.) The OLAP market has moved very slowly towards standardization, but this is a significant moment, even a tipping point. In a conversation five years ago, Oracle executives agreed that MDX was a fine language, but said they would not support it, because that would be to acknowledge that Microsoft was the thought-leader in the OLAP marketplace. It's that old PR strategy: deny in public, agree in private. And in a sense their strategy worked, because without a standard language, the OLAP market could not begin to commoditize.
There is still a long way to go towards OLAP interoperability. Servers differ widely in their support of MDX. Unlike SQL, the MDX language is not in the hands of an independent standards organization; even the originators of the de facto standard, Microsoft, have not released a specification for MDX or XMLA for several years.
A query language is no good without an API to issue queries, and APIs only exist in Microsoft's own technologies: COM (OLE DB for OLAP), .NET (adomd.net) and web services (XMLA).
I have been advocating olap4j as the standard API for Java-based OLAP, but it has yet to receive public backing from vendors outside the open source community. And there are no OLAP APIs for languages such as python, perl, and php.
The final point of concern is the emergence of Simba as virtually the sole supplier of MDX, OLE DB for OLAP and XMLA technology. Simba is an excellent company, who understand MDX very well, and have invested in building a technology stack. But they also benefit from a close relationship with Microsoft. (Remember those specifications for MDX and XMLA I referred to earlier? Though they have not seen public updates for several years, I'm sure those specifications still exist behind the walls of Castle Redmond, and are available to Microsoft's partners.)
As far as I am aware, Simba have been responsible for all of the projects in the last few years to bolt MDX support on to existing servers and applications. (With a sole exception: I was never able to find out where JasperSoft sourced the technology for its ODBO Connect product.)
To summarize, this is a milestone moment in the development of OLAP technology, but there is still cause for concern. OLAP APIs exist only for a small number of languages, vendors show little inclination to provide true interoperability, and the key technology is provided by a small number of players.
You can help. If you are a user of OLAP technology it is in your interests to see the emergence of standards in the OLAP marketplace. So, please ask your vendor what they are doing about interoperability. Ask them whether there are OLAP clients, other than their own, that run on their server. And ask them for APIs to connect to their server from all of the languages you use in your organization. Then, we may move a little closer to the goal of OLAP for all.