Opinion Poll: Are PRINT statements considered harmful?

Today during a discussion a point came up around the role of PRINT statements in production code. While most data access today is routed through a data access layer (typically .NET or JDBC) and is focussed on consuming result sets (or executing U/I/D nonquery stuff) we were wondering on what you use PRINT statements for. In the long past, I would have said that the print statement is probably the best way for debugging, but in today’s world with easy access to the T-SQL debugger, a developer is probably much better off without PRINT.

With SqlClient, we consume the PRINT events using the InfoMessage event, but in practice I wonder how many of you actually rely on that. Please comment on this post to share your experiences with PRINT and if you think it is good / bad / evil in today’s world 🙂

Implementing MDX Drillthrough in SSRS

Let’s say for some reason your users want to implement MDX DRILLTHROUGH statement (equivalent to the cube action provided by most OLAP browsers) in SSRS. Here’s a step-by-step way to implement this.

For the purposes of this walkthrough, we are using the standard AdventureWorks Analysis Services database. You can obtain this and the related DW database from http://msftdbprodsamples.codeplex.com/. Do note that you have to manually deploy and process the database after opening the Adventure Works.sln file from its default location of C:Program FilesMicrosoft SQL Server100ToolsSamplesAdventureWorks Analysis Services Projectenterprise

Our objective is to implement two reports:

1. The parent report will list the top 10 products along with their sales amount totals

2. The child (drillthrough) report will display a raw DRILLTHROUGH for the first 500 rows and get back the product quantity of the individual order, along with the order number and date the order was placed

Step 1. Verify the AS database is deployed and processed

Step 2. Here is our (pretty basic) MDX query for the Top 10 listing for current products:

WITH MEMBER PKey AS
[Product].[Product].CurrentMember.Properties(“Key0”)
select {[Measures].[Reseller Sales Amount], PKey } on 0,
(TopCount([Product].[Product Categories].[Product], 10, [Measures].[Reseller Sales Amount])) on 1
from [Adventure Works]
where [Product].[Status].[Current]

Why the calculated member PKey? You will see later.

Step 3. Capture the DRILLTHROUGH query in Profiler

Since writing the DRILLTHROUGH statement by hand can be a bit of a challenge, here it is captured from SQL Profiler:

DRILLTHROUGH  Select  ([Measures].[Reseller Sales Amount],[Product].[Product].&[358])  on 0 From [Adventure Works] RETURN [Reseller Sales].[Reseller Order Quantity],[$Employee].[Employee],[$Delivery Date].[Date],[$Sales Territory].[Sales Territory Region],[$Reseller Sales Order Details].[Sales Order Number]

You can see the product key is highlighted. This is actually the key column syntax as can be seen from the ampersand prefix. So now you know why we selected the PKey calculated member in the previous query.

Step 4. Create the parent report

The first step is to create a shared data source to the SSAS database:

image

Next, we actually create the report. We select the New Report option and use the above shared data source. In the Query Designer, we switch to Query Mode and type in the MDX query we developed earlier:

image

Once this is done, select Tabular report, and move all the columns into the Details section of the report. Title the report as MainReport.

image

In the generated report, delete the PKey column.

Step 5. Create the drillthrough report

This is the tricky part. Normally, the MDX query designer does not support DRILLTHROUGH SELECT syntax. Hence we need to use a workaround. Please note that this workaround may not be officially supported by Microsoft.

We start the same way, by creating a new report and referencing the shared data source. But when you launch the query designer please switch the query type to DMX instead of MDX.

image

After this is switched, also switch to query mode as done before. In the space at the bottom, type in the ‘DMX’ query which is actually our MDX DRILLTHROUGH SELECT query. However now we do need to parameterize the query to accommodate the PKey parameter:

DRILLTHROUGH MAXROWS 50 Select  ([Measures].[Reseller Sales Amount], StrToMember(‘[Product].[Product].&[‘ + @PKey + ‘]’))  on 0 From [Adventure Works] RETURN [Reseller Sales].[Reseller Order Quantity],[$Employee].[Employee],[$Delivery Date].[Date],[$Sales Territory].[Sales Territory Region],[$Reseller Sales Order Details].[Sales Order Number]

Before you can click on OK though, you need to setup the parameter as well. You do that by clicking on the Query Parameters button:

image

We provide a dummy value of 394 so that the fields can be retrieved. The actual value, of course, will be provided by the drillthrough action later.

image

Select the tabular layout and move all the fields to the Details section. Name the report DrillThroughReport.rdl. Finally, set the report parameter PKey type as Hidden:

image

Step 6. Create the drillthrough action

Back to MainReport.rdl, right click on the Product text box and select Text Box properties. In the Action tab, you need to set up the Drillthrough (SSRS this time… don’t get confused by the similar term Smile)

image

We also change the hyperlink look and feel for good measure:

image

And that does it for our reports:

image image

Final Notes

How ‘legitimate’ is it to masquerade a MDX DRILLTHROUGH as a DMX query? As I said before, this is not officially supported. You can refer the to the MS Connect posting at http://connect.microsoft.com/SQLServer/feedback/details/126175/reporting-services-drillthrough-mdx-queries for the ‘won’t fix’ response.

The main reason for my documenting the approach above is that in the specific case I was interested in, the MAXROWS clause is very important. Of course one can argue that using MDX the same can be achieved, but then it is a matter of preference in the end.

BTW, Chris Webb also shares his perspectives on this at http://cwebbbi.wordpress.com/2009/06/16/implementing-analysis-services-drillthrough-in-reporting-services/

If you liked this posting, please rate it! In any case please do take a minute and leave comments, questions etc.

.NET Debugging Quick Start

Many a time I am asked how to get a head start with debugging .NET issues – hangs / crashes and most commonly, memory issues. So I assembled this list of resources which helps you get started. In addition, if you are a Premier Support subscriber, you can avail of our most excellent .NET Debugging WorkshopPLUS conducted by my team (Premier Field Engineering).

I hope you find the links useful and if you do I would appreciate some comments and / or you rating this post!

Failover cluster (group) maximum failures limit

My colleague reported that during testing forced failover for a SQL database engine instance, it just ‘failed’ and refused to fail over to the other node in a 2-node cluster. The failure in this case was initiated by shutting down the local service for the clustered instance – which is tantamount to failing the clustered instance itself.

This behavior was slightly unexpected. After some research, we traced it to the ‘Maximum failures in the specified period’ setting at the cluster group (service application) level:

image

It turns out that the testing activity involved some failures already due to which the above limit was already reached. Subsequently, when the SQL service level failure was initiated, the cluster service did not fail it over to the other node and left it in the failed state.

During this investigation I found some articles which are very useful in this:

Moral of the story: When performing failover drills or testing, it may be appropriate to increase this value to a higher number, such as 5 or 10 for the duration of the testing. Subsequently the value may be reset back to 1 or 2.

FYI when you look at the cluster log, this is the message which is recorded when the limit has been reached (and is therefore disallowing restarts):

0000088c.00001038::2012/03/07-06:09:09.834 WARN  [RCM] Not failing over group <groupname>, failoverCount 8, failover threshold 4294967295, nodeAvailCount 1.

Hope this helps!

MDX Studio Quick Tips

Recently I had to use MDX Studio for some MDX query tuning. 2 quick tips:

Also very quickly, if you are finding that the Perfmon section in MDX Studio shows 0 for most values such as ‘Cells calculated’ then try running the MDXStudio.exe with the ‘Run as Administrator’ option.

Also take a look at Ashwani Roy’s SQL Bits session ‘Supercharge MDX performance using MDX Studio’ which is available from https://www.sqlbits.com/Sessions/Event6/supercharge_mdx_performance_using_mdx_studio

TEMENOS T24 Core Banking Optimized on Microsoft SQL Server Database Platform

I found these links today in response to a customer question around ‘real world’ benchmarks for financial applications running on SQL Server. These benchmarks describe the TEMENOS T24 Core Banking system, which is probably as ‘real world’ as it gets.

http://blogs.technet.com/cfs-file.ashx/__key/CommunityServer-Blogs-Components-WeblogFiles/00-00-00-85-48-Files/4617.Benchmark-Results-for-Temenos-T24–with-SQL-Server-2008-R2-on-Intel_2D00_based-NEC-Servers.pdf

http://download.microsoft.com/download/B/2/3/B23E0B02-AA00-4921-8A76-B4384B6197DD/sql-temenos-t24.pdf

 

Parallel Data Warehouse resources

I’ve recently started learning about SQL Server Parallel Data Warehouse (PDW) appliance. In the course of learning, I came across some links and resources in connection with this appliance, which I will share in this blog post. I will keep it updated as much as possible.

Learning resources:

Community blog posts:

I will continue to gather links and post them here as I come across them. In the meantime, I hope the above help you!

SQLDiag Configuration Tool released

 

My colleague and friend, boB Taylor (the spelling is not a typo – please visit http://www.opsvault.com/meet-our-contributors and see why) has recently released a GUI tool which allows you to configure the XML files required for SQLDiag to capture specific types of events, counters etc.)

Download it from http://sdct.codeplex.com

Please review, test, blog about it and provide feedback as you see fit.

bOB blogs at OpsVault. His posts can be easily retrieved from http://www.opsvault.com/author/bobtay/

OPTION(RECOMPILE) redux (a.k.a. Parameter Embedding Optimization not working)

A long time ago, I had blogged about the perils of ‘wildcard’ query patterns. As a response to one of the comments in that post, I learnt about a new optimization introduced in SQL 2008 wherein the OPTION (RECOMPILE) hint would help in these kind of cases. Ever since then, I had used this in some customers; but recently, I found that on SQL 2008 R2 and even in SQL 2008 SP1, the behavior was not working correctly.

Recently, I found the reason for this issue from some other sites, and I also found the official name for this enhancement: Parameter Embedding Optimization. It turns out that, based on some bug reports, this optimization was disabled starting in SQL 2008 CU4 (and also disabled in SQL 2008 R2 RTM). The fixes for the issue are in SQL 2008 SP1 CU5 and SQL 2008 R2 CU5 respectively.

Here are the links which cover the details, and I hope they help you!

window.open without address bar

Recently we were struggling with trying to figure out how to suppress the address bar for a popup window opened using JavaScript’s window.open method. Normally, there is an option there which allows you to specify ‘location=no’ and the address bar is expected to be hidden. However, no matter what we tried, this did not work for us.

Later on I chanced upon an Internet Explorer setting which actually controls the final display. There is a security setting ‘Allow websites to open windows without address or status bar’:

image

This setting needs to be set to ‘Enable’ for the respective zone (such as Trusted sites etc.) for the address bar display to be suppressed.

Hope this hint helps!