PowerPivot/Excel/Sharepoint and SSRS – should they merge?

I’ve been doing a fair amount of work with SSRS over the last few days, and with PowerPivot also fresh in my mind it got me thinking about the amount of overlap between SSRS and the PowerPivot/Excel/Sharepoint stack. Of course anyone who’s had to try to sell a MS BI solution to a potential customer over the last few years will have had to deal with conversations like this:

Customer: So, what is Microsoft’s solution for building BI dashboards?
Consultant: Well there’s SSRS, or if you want to build an SSAS cube you can use PerformancePoint, or maybe Excel and Excel Services, or you can go with any of these 50 third-party tools…it depends…
Customer: I’m confused already!

But just about any large software company has a certain amount of overlap between their products, that’s just life. However, that doesn’t mean that sometimes some rationalisation of products isn’t a good idea.

Let’s take a look at some of the things you’d want to do when building a dashboard, and how you can achieve them with both stacks:

Requirement SSRS PowerPivot/ Excel/ Sharepoint Comments
Get data from a number of different sources Create data sources and then datasets to return the data you want Import data into PowerPivot ‘tables’ from Excel, RDBMSes, OData feeds There’s a slight difference between the data sources here, but the most important case is always going to be getting data from a RDBMS, which both do well.

The key difference, though, is that in general with SSRS you get data on demand through parameterised queries, whereas with PowerPivot you import all the data you’re ever likely to need up front.

Integrate that data No real solution here, though SSRS developers have wanted to be able to do joins on datasets for a while. The new R2 lookup functions partly address this. Create joins between PowerPivot tables PowerPivot has the obvious advantage here, although for SSRS you can argue that in most cases any data integration should be happening upstream in your ETL.
Perform calculations on that data Use SSRS expressions Use DAX calculations I’d say that SSRS expressions, while as not powerful as DAX, are easier for most people to understand; however there are a lot of things that only DAX can do.
Create reports from that data Use BIDS if you’re a developer, or Report Builder if you’re a power user Use Excel or any client tool that speaks MDX (including SSRS) For developers, BIDS is a great tool for creating reports. However SSRS has always struggled with Report Builder – in my experience users find it too difficult. And that’s where Excel comes into its own: it’s a powerful tool and most end-users are familiar with it.
Publish reports to a wider audience Deploy up to your SSRS server Publish to Excel Services/Sharepoint The advantage SSRS has here is that most companies have no problem with the IT department setting up an SSRS server. On the other hand, Sharepoint is a Big Deal. If your company has a Sharepoint strategy, and is planning on installing Sharepoint 2010 Enterprise Edition, you’ll be fine with PowerPivot. If not, and I guess many companies are in this position, you have a problem.
Export reports to a variety of formats SSRS handles exporting to a lot of different formats Export to Excel isn’t a problem, but other formats are a bit trickier (though doable) SSRS has the clear advantage here
Schedule report refresh Again, SSRS has a lot of options for controlling when reports are refreshed PowerPivot’s functionality for scheduling when data is refreshed is a bit v1.0 SSRS has the advantage again

Anyway, you get the idea – there’s a fair amount of overlap and some things are done better by one tool, some things are done better by the other. Isn’t it, though, a bit of Microsoft’s time, money and energy to develop two parallel BI stacks? If they could merge in some way, it would mean less effort spent developing duplicate functionality and a more coherent message for customers to hear.

How could this be done, you ask? Well here are some vague ideas I had about what you’d need:

  • Inside SSRS – BIDS as well as Report Builder – in addition to the existing functionality for bring data into datasets, and possibly in the long term as a replacement for it, you get the option of building a PowerPivot model to act as the main source of data for your reports. For Report Builder especially I think this would be a winner, given that the PowerPivot UI for building models is already aimed at the same power users that Report Builder is aimed at.
  • The fact that you need to load all of your data into a PowerPivot model upfront is both an advantage and a disadvantage, depending on your scenario. When you know the data’s not going to change much, or you’ve got relatively small amounts of data, it’s good because you get joins and fast query performance. But if the data changes a lot or you don’t want the overhead of loading it into PowerPivot then you’d need the option to pass requests straight through PowerPivot back to your sources – so maybe PowerPivot would need something like ROLAP mode, or proactive caching, or the ability to make its tables work like existing SSRS datasets and send parameters to them.
  • Include proper support for MDX queries in SSRS reports (my old hobby horse). This would involve developing a proper, fully-functional MDX query builder (not the rubbish one SSRS has right now – a standard MDX query generator across all MS products which was also available as a control for custom development would be ideal) and the ability to bind the results of an MDX query direct to a tablix (and no messing around with mapping field names to rowgroupthingies in the tablix control please). If power users didn’t have to worry about tablixes and could just build their queries as easily as they could in an Excel pivot table, Report Builder would be a much more popular tool. I think many developers would appreciate it too. Once all the data you need for your report is in a PowerPivot model, and you have full MDX support in SSRS, the business of report design is much easier. You also no longer need to join datasets because the data is already joined in PowerPivot, you have a powerful calculation language in DAX, and query performance is extremely fast. Oh, and with this functionality in place you could probably kill off PerformancePoint too and no-one would complain…
  • Blur the line between Excel and SSRS. There’s been talk about being able to author SSRS reports in Excel for a long time (whatever happened to the Softartisans technology MS licensed?), but nothing’s ever come of it. Why not also have the option within SSRS to take a range from Excel Services and make that the body of your report? So your report is essentially still a fragment of an Excel worksheet, but it’s just surfaced via SSRS which then handles the refreshing and rendering to different formats.
  • You’d also need SSRS to be able to schedule the refresh of your PowerPivot model, but that should be very doable; it would be great if it could refresh different parts of the model at different times. SSRS would also maintain control over report security, rendering, folders etc etc.

The end result would be that this PowerPivot/Excel/SSRS hybrid would give you the best of both worlds. I also have some ideas about how PowerPivot and SSAS should be integrated which I might get round to blogging about soon too, that would fit nicely with this vision of the future.

What are the chances of all this happening? Practically zero. It would involve the SSRS team, the SSAS team and the Excel team setting aside their differences, co-operating, and possibly sacrificing large chunks of different products. But it’s a nice thought to kick around…

SSRS and SSAS-Sourced Parameter Dataset Performance Issues

Ahhh, Reporting Services and Analysis Services integration – a never ending source of pain and frustration! Although I shouldn’t complain because it’s been quite lucrative for me in terms of consultancy work…

Anyway, recently I was tuning a SSRS report based on a SSAS cube for a customer. Looking at Profiler I could see a number of slow queries being executed, which was strange given that it was a fairly simple report. It turned out that during the design phase this report had had a number of parameters created in the SSAS query designer that had later been deleted; however, when you delete a parameter in the SSAS query designer BIDS does not delete the hidden dataset that it is bound to. What’s worse is that when an SSRS report is executed all dataset queries are also executed, even if the datasets aren’t used anywhere in the report, which means you get the overhead of running extra queries. It’s an easy mistake to make and in this case the execution of unused datasets was adding several seconds to the execution time of the report.

You can reproduce this problem very easily by creating a simple report based on the Adventure Works cube. Once you’ve created the data source, open the query designer, drag the Internet Sales Amount measure onto the grid, drag the Customer hierarchy from the Customer dimension onto the filter pane and check the Parameters box:


Now close the query designer and reopen it, then remove the Customer hierarchy from the filter pane, close the query designer again and delete the report parameter. When you Preview the report you’ll see the following in Profiler:


The highlighted row shows the hidden dataset is being executed. What you need to do to fix this is to right-click on your data source and check the Show Hidden Datasets option:


You’ll then see the offending, automatically-generated, hidden dataset and you can delete it:


Luckily, BIDS Helper has functionality to find unused datasets in your reports for you:

And there’s more! What I found really interesting about this parameter dataset query was how long it was taking to execute. In this example 2.5 seconds, even on a warm cache, seems like a very long time to me even though there are a lot of members on the Customer hierarchy. Once the report is deployed that goes down to a consistent 2.1 seconds, and when I run the same query through SQL Management Studio it goes down to 1.5 seconds. Why the difference in execution times? I’m not sure, but I suspect it’s a combination of the connection string properties used and the use of a flattened rowset. In any case, 1.5 seconds is still slow and it’s certainly not good if you actually do want to use a query like this in a dataset bound to a parameter.

Luckily, if our parameter datasets are causing performance problems, we can usually rewrite the queries involved to make them faster. Here’s the original query from the parameter in the example:

MEMBER [Measures].[ParameterCaption] AS
MEMBER [Measures].[ParameterValue] AS
MEMBER [Measures].[ParameterLevel] AS
FROM [Adventure Works]

If we decide that we can make do without the All Member and the level-based indenting that goes on in the parameter dataset (this is an attribute hierarchy, after all, so there’s just one level), we can use the following query in the dataset instead:

FROM [Adventure Works]

Once the first query above has been replaced with the second, and the report parameter has been hooked up to use the new fields, Profiler shows that the time taken to execute the parameter dataset has gone down to around 0.7 seconds:


That is, of course, almost 2 seconds faster than the original query in Preview mode and almost 1.5 seconds faster than the original query in the deployed report. Not a lot on its own but certainly noticeable, and if you have more than one large parameter the cumulative gain could be quite significant. If you create a separate OLEDB connection to the cube and use the second query in a dataset, the execution time is even faster, going down to around 0.45 seconds:


Incidentally, some of the more astute may be asking why I need to include MEASURES.DUMMY in the query above when I can use an empty set on the columns axis instead. Two reasons: one, if you use an empty set on columns in the OLEDB connection you get no rows returned; two, I noticed when the query was being executed in SSRS a Query Subcube event was raised suggesting measure data was being requested from the cube – this didn’t happen when I ran the query in SQL Management Studio. I suspect both problems are something to with SSRS using a flattened rowset, so I’ll investigate and post back here when I get an answer.

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