Tuesday, October 12, 2010

RS.exe and rss Scripts for Automation of SSRS 2008 Administrative Tasks

Download .rss script

Most people that work with SSRS (2005, 2008, 20080 R2) are aware of two ways to deploy Reporting Services catalog items (reports, data sources, shared datasets, images, etc.). These include deploying directly from BIDS (Visual Studio) and by using Report Manager to upload files. There are also a number of web services available that enable us to do this this in a programmatic, automated fashion that allow for things such as dynamic data sources so that we can deploy reports to any environment without having to modify data source properties manually and specifying where in the Report Manager folder hierarchy we want our reports installed - again without having to modify data sources or data sets or references to either.

The following web services are available with for administrative tasks in SQL Server 2008 R2. Note that there is also a ReportExecution2005 web service that provides methods for actually executing reports.
  1. ReportService2005
  2. ReportService2006
  3. ReportService2010
ReportService2005 was used for SSRS instances that are running in native mode.
ReportService2006 was used for SSRS instances that are running in SharePoint integrated mode.
ReportService2010 ties 2005 and 2006 together so that one web service works with both native and SharePoint integrated mode.

While you can work directly with these web services using your programming language of choice, Microsoft was kind enough to create RS.exe. This console application acts as a wrapper for these web services. It is installed with SQL Server and like any other executable it can be called by tools like NANT, MSBuild, InstallShield, etc.

My need for this tool arose when I was developing a set of reports for a commercial product that required installation through InstallShield. The development environment included ANT which we also had call RS.exe for automated deployment in an automated build environment.

Now I'll show you how to use RS.exe from the command line. I won't go into detail about how to use it from specific tools as that should be straightforward for anyone that is familiar with the tool they are using.
Below is a sample RS call with three input parameters.
-i is the file that contains your rss script. More on that later.
-s is the address of your ReportServer web service
-e is the web service end point. Remember from above that there are multiple web services available and you can target any of these endpoints using RS.

  -i SSRSDeploy.rss
  -s http://localhost/reportserver
  -e Mgmt2010

Now that we know how to call RS, the key to making it useful is your custom .rss (Reporting Services Script). It is in these scripts that we can write custom code to deploy reports, data sources, images and create folders as well as delete items.

I have posted a sample rss script that has the following generic methods.
CreateFolder: Creates folders in Report Manager
PublishItem: Publishes reports and shared datasets
PublishImage: Publishes images
DeleteItem: Deletes any item

These methods are essentially wrappers around the rs.CreateCatalogItem, rs.DeleteItem, rs.CreateFolder, rs.SetItemDataSources, and rs.SetItemReferences methods. They add additional exception handling and deal with the nuances of publishing reports in locations different than specified in your Visual Studio project and .rdl files.

Note the use of what are referred to as Global Variables. You can pass values into your rss scripts by using Global Variables. You don't declare these variables you simply refer to a non-declared "variable" in your rss script and RS is smart enough to know that you want to set them at the command line. The way to set them is by using the -v argument. See below for another example.

  -i SSRSDeploy.rss
  -s http://localhost/reportserver
  -v rootPath="/Sample"
  -v DWServerName="localhost"
  -v DWDatabaseName="MyDataWarehouse"
  -v sourceFilePath="C:\SourceCode\SSRS"
  -e Mgmt2010

With the sample script you should be able to quickly and easily create an automated process for working with your Reporting Services instances.

Download .rss script

Sunday, October 3, 2010

Nested Loops Join - No Join Predicate

I was recently troubleshooting a severe query performance issue when I ran into a query plan that used a nested loops join to combine data from two tables. The join was 97% of the cost. When I looked closer I saw that there were no join predicates specified. The join in the query looked pretty straightforward to me and used a single column on each side. Why would the optimizer do what equated to a cartesian join?

It turns out the query was a little more complicated than it looked. I was actually joining two views that were part of a view-based (non-persisted) dimension model. I was joining on logical primary and foreign keys which made sense.

When I dug into the views I found that one of the key columns was based on a user-defined fuction that was converting a datetime to an integer value so that it could be used to join to a date dimension view. Once I changed the underlying view to apply the same logic as the UDF at the view level, so that a call to the UDF was unecessary, the query executed within a second as expected.

Other behavior that I noticed was that if I changed the inner join to a left join, the optimizer came up with a different much more efficient plan. This appears to be a flaw in the optimizer but I would like to speak to someone at Microsoft before making that claim.

The lesson learned here is that if you have a poorly performing query due to a nested loops join with no join predicate(s) it's not ncessarily the case that you're missing join criteria in your query (as all the posts I was able to find seemed to point to). The culprit could be a UDF on a join column.