Russell Christopher's Semi-Useful BI Musings : SQL Analysis Services

SQL Server 2008 R2 CTP2 hits the streets and I am psyched!

russch — Tue, 11 Aug 2009 15:00:00 GMT

http://performancepointblog.com/2009/08/omg-sql-server-2008-r2-ctp2-hits-the-streets/

SQL Analysis Services error processing ROLAP partitions against Teradata

russch — Mon, 12 May 2008 18:59:00 GMT

Today I was playing around with stacking SSAS on top of Teradata. Essentially I have AdventureWorks DW moved over into Teradata and I’m trying to build a dumbed-down version of the AdventureWorks cube against it.

Things went fairly well while my partitions were MOLAP. But when I started changing some of them to ROLAP, SSAS threw the following exception when I tried to process:

Errors in the high-level relational engine. The following exception occurred while the managed IDbConnection interface was being used: The isolation level is not supported by this version of Teradata Database.

After a bit of playing, I found that the issue had to do with including aggregations on these partitions – you can’t. When I set the aggs to 0%, everything worked perfectly. Shortly afterwards, a colleague forwarded me additional information on the subject, which will be included in a soon-to-be released Teradata/SSAS whitepaper:

ROLAP aggregations: An Analysis Services cube partition that uses ROLAP partition storage with the Teradata Database, must be defined with zero aggregations. This issue is discussed in Designing Partition Storage and Aggregations section. Recommendation to use AJI for performance

Save your SSAS browser queries for re-use: new add-in

russch — Tue, 06 May 2008 17:17:00 GMT

File this under "reclaim a few second of your life". If you build semi-complex pivots in the SSAS browser, you probably get annoyed when you have to rebuild them time and time again after you close the cube designer. Well, Yossi Elkayam has written the Analysis Services Browser Views add-in which allows you to save the underlying queries so you can re-use them later. Great idea!

SQL Server 2008 "Katmai" CTP5 released

russch — Mon, 19 Nov 2007 22:18:00 GMT

Just got an invite from Microsoft Connect to download the November CTP of SQL 2008....you can, too!

http://www.microsoft.com/downloads/details.aspx?FamilyId=3BF4C5CA-B905-4EBC-8901-1D4C1D1DA884&displaylang=en

Alerting without SQL Server Notification Services

russch — Thu, 25 Oct 2007 02:41:00 GMT

Last week I worked with a customer who wanted to give users the ability to create and subscribe to alerts for changing KPI Values. This is a pretty standard scenario, and one we covered with BSM 2005. However, with the “loss” of Notification Services in SQL 2008, PerformancePoint server does not include alerting functionality out of the box (which stinks, but that’s another rant).

So, the customer was interested in creating a simple “SQLNS-less” alerting system that could send users email when KPI X’s value went up or down by a certain % or value. I put together a POC for them which uses SQL Integration Services (SSIS) to do the work. Note that this isn’t necessarily a best practice since as far as I know Microsoft doesn’t yet have any real guidance around how to replace SQLNS.

There were actually a bunch of different ways we could have approached this:

· Biztalk – rejected because it takes a while to grow BTS expertise and we’d be hitting a small-ish problem with an awfully big hammer

· Managed code and/or services which took care of alerting from soup-to-nuts – rejected because we didn’t want to recreate the wheel

· Managed code and/or services which managed part of the alerting process (detecting a change and dropping an event in the Windows Event log or raising a WMI event) and MOM or other operational management software to do the actual heavy lifting. We’d rely on MOM to see the newly added event and send whatever notice to whatever endpoint we specified. We rejected this because we couldn’t count on everyone having MOM running.

That pretty much left us with SSIS, which could do much of the work for us.

Here’s what this simple POC does:

· Collects “alert subscriptions” in a SQL table. Each subscription includes the email address to which we’ll send an alert, the KPI name in adventure works we’re monitoring, the value of that KPI when the subscription was created, and the “change factor” (up or down X%) which will cause the alert to fire

· Uses an SSIS Ipackage which reads each alert subscription and:

o Grabs the current value for the KPI we’re dealing with in the subscription currently being processed

o Compares the current value of the KPI to the “historical” one stored in the subscription table and sees if we’ve hit our change factor or not

o Sends an email to the user if we have

The POC is rough and makes no attempt at intelligence (grin). For example, we’ll happily send the same alert to a user over and over again when the package is run after we’ve hit the “change factor” for the subscription in question. Extra logic needs to be added to improve real-world usability of this thing.

Here are the components:

· A table which holds subscriptions:

USE [Catcher]

/****** Object: Table [dbo].[kpiDemo] Script Date: 10/22/2007 09:24:53 ******/

SET ANSI_NULLS ON

SET QUOTED_IDENTIFIER ON

CREATE TABLE [dbo].[kpiDemo](

[emailAddress] [nvarchar](50) NOT NULL,

[kpiName] [nvarchar](50) NOT NULL,

[kpiCurrentValue] [float] NOT NULL,

[kpiMovement] [float] NOT NULL,

CONSTRAINT [PK_kpiDemo] PRIMARY KEY CLUSTERED

(

[emailAddress] ASC

)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]

) ON [PRIMARY]

INSERT KPIDemo VALUES (‘someEmailAddress@domain.com’, ‘Channel Revenue’, 80000000, -0.1) -- Alert someEmailAddress when the Channel Revenue KPI value in AdventureWorks (with a current value of 80M) declines by 10%

· The package itself (attached below)

I had a bear of a time successfully reading KPIStatus, KPIValue, and KPIGoal values in the package. In essence, when I constructed an MDX query and fired it from an OLEDB Data Source or Data Reader, I’d get the following error message:

The output "OLE DB Source Output" (11) references an external data type that cannot be mapped to a Data Flow task data type. The Data Flow task data type DT_WSTR

I’d find that only two of the three columns I asked for came back, as well. The third (usually KPIStatus) would disappear into the ether. This made me sad and evidently is a known issue. I found a thread about it here but discovered the workaround did not help me:

http://forums.microsoft.com/TechNet/ShowPost.aspx?PostID=215075&SiteID=17

I ended up going with a Script Component acting as a source, and used code stolen from this great blog entry to get my values back:

http://blogs.msdn.com/olivier_pieri/archive/2004/12/06/275811.aspx

All standard disclaimers apply – use this at your own risk, it is unsupported and could burn down your house if left running unsupervised.

Bad password trying to process an SSAS cube against Oracle

russch — Fri, 19 Oct 2007 21:29:00 GMT

Shout-out to my homies Chris and Thanh.

Depending on how you set up the impersonation settings on your Analysis Services cube’s data source to Oracle, you may run into the following error when trying to process:

If you bump into this, open up your data source and choose the Impersonation Information tab. Make sure Default is selected. Next, edit your data source, enter your Oracle credentials and don’t forget to select the save password checkbox.

That should do it for you.

Dell and Microsoft engineer BI offering

russch — Thu, 20 Sep 2007 20:22:00 GMT

Today at SQL PASS, Dell and Microsoft announced a new set of Business Intelligence and Data Warehousing solutions. They include a stack of server hardware, storage arrays, operating system, database and analytics software, management and reporting tools. The entire solution is based on the hardware and software many customers are using right now.

What is really cool about these offerings is they answer the oft-asked question: “what sort of hardware do I need for my DW/BI project?”: Three reference configurations have been created: one terabyte, two terabyte and four terabyte systems for data warehousing databases using SQL Server 2005. Dell and Microsoft worked together to execute various tests and analyze performance results of a sample business intelligence and data warehousing system under load. The testing was designed to validate the platforms for business intelligence and data warehousing, to provide the stability and performance of the hardware systems, and to define the reference configurations I mentioned earlier.

From what I understand, we’ll essentially be including all the goodness in the SQL 2005 BI stack + ProClarity. Now that PerformancePoint 2007 is upon us, the offering will be reconfigured to include PPS at some point in the near future.

More official details should be available at ~~www.dell.com/bi~~ http://www.dell.com/sqlbi a little later today. It doesn't seem like the site is up yet, however.

Update:

Here is a link to the actual 1/2/4 TB reference configuration to see how they did it:

http://www.dell.com/content/topics/global.aspx/sitelets/solutions/software/db/microsoft_sql_2005_pr?c=us&cs=555&l=en&s=biz

...and another to an article on this event:

http://informationweek.com/news/showArticle.jhtml?articleID=201808018

Mosha Pasumansky releases new Analysis Services MDX tool

russch — Wed, 19 Sep 2007 16:00:00 GMT

Mosha just announced the availability of a new tool he wrote called MDX Studio:

MDX Studio is tool which helps users of Microsoft Analysis Services to analyze complex MDX expressions, monitor performance characteristics of MDX queries and get insight into how MDX interacts with other UDM features such as attribute relationships. MDX Studio provides unique visualization representation of MDX expression and allows the user to interact with different stages of MDX execution.

The tool itself can be downloaded here.

At SQL PASS? Don't miss these sessions!

russch — Wed, 19 Sep 2007 04:35:00 GMT

Right now I'm in Ocean Shores, WA for team meetings, so I won't be attending SQL PASS. However, if I was, I'd be sure to hit the SQL CAT sessions being presented:

https://www.sqlpass.org/summit/Lists/2007%20Summit%20Sessions/SQL%20CAT%20Sessions.aspx

These guys know their stuff, and then some.

For you hardcode BI types, I would especially recommend these two:

DBA-416-M Building and Deploying Large Scale SSRS farms using Lessons Learned from customer deployments

DBA-415-M Building & Maintaining large cubes using Lessons Learned from customer deployments

I sat on in "internal-ish" versions of these suckers about two months ago at TechReady5, and they were both really informative.

Hot off the presses: resolving MDX query performance bottlenecks

russch — Wed, 29 Aug 2007 12:51:00 GMT

Carl Rabler et al have just released a really nice looking best practives article on how to resolve query perf bottlenecks. Get it here:

http://www.microsoft.com/downloads/details.aspx?FamilyId=975C5BB2-8207-4B4E-BE7C-06AC86E24C13&displaylang=en

AMO Error when adding an attribute to an existing dimension: The transaction cannot be committed because one or more objects were invalidated during the transaction

russch — Fri, 15 Jun 2007 01:35:00 GMT

Today’s tale from the front: I needed to write some POC code and kept on running into the error below when attempting to Update() the dimension I had added an attribute to:

The cube with the ID of '<cube>', Name of '<cube>' was invalidated by operations in the transaction.

Errors in the metadata manager. The Dimension with the ID of ‘<dimension>', Name of ‘<dimension>' was invalidated by operations in the transaction. Errors in the metadata manager. The transaction cannot be committed because one or more objects were invalidated during the transaction.

(Very) long story short, I forgot that I needed to use not only the option ExpandFull, but the option AlterDependents as well since the dimension was already related to a measure group in the cube.

Here’s some code that:

· Modifies an existing DSV, changing a table in the DSV to a named query and adding an additional field to the named query

· Adds the new column to an existing dimension in the cube

· Processes the cube

Microsoft.AnalysisServices.Server server = new Server();

server.Connect("localhost");

Microsoft.AnalysisServices.Database database = new Database();

database = server.Databases.GetByName("aDataBase");

Microsoft.AnalysisServices.DataSourceView dsv2 = database.DataSourceViews.GetByName("aDSV");

// The sample DSV contains one table - Grab it.

DataTable dt2 = dsv2.Schema.Tables[0];

// Remove certain existing properties from the DataTable and replace them with

// new ones which are appropriate when using a Named Query

dt2.ExtendedProperties.Remove("TableType");

dt2.ExtendedProperties.Add("TableType", "View");

dt2.ExtendedProperties.Remove("IsLogical");

dt2.ExtendedProperties.Add("IsLogical", "True");

// Define more information about how this new table should behave inside the DSV:

// What is it's name, what is the table's SQL statement, etc.

dt2.ExtendedProperties.Remove("DbTableName");

dt2.ExtendedProperties.Remove("FriendlyName");

dt2.ExtendedProperties.Add("DbTableName", "DimAccount");

dt2.ExtendedProperties.Add("FriendlyName", "DimAccount");

dt2.ExtendedProperties.Remove("QueryDefinition");

dt2.ExtendedProperties.Add("QueryDefinition", newSQLStringForQuery);

DataColumn dc = new DataColumn();

dc.Caption = "New Attribute Thing";

dc.ColumnName = "NewAttribute";

dc.MaxLength = 300;

dc.ExtendedProperties.Add("FriendlyName", "New Attribute Thing");

dc.ExtendedProperties.Add("DbColumnName", "NewAttribute");

dt2.Columns.Add(dc);

dsv2.Update();

dsv2 = database.DataSourceViews.GetByName("Adventure Works DW Original");

Microsoft.AnalysisServices.Dimension dim = database.Dimensions.GetByName("Dim Account");

DimensionAttribute attr;

attr = dim.Attributes.Add("CustomMembers");

attr.KeyColumns.Add(CreateDataItem(dsv2, "dbo.DimAccount", "CustomMembers"));

attr.NameColumn = CreateDataItem(dsv2, "dbo.DimAccount", "CustomMembers");

dim.Update(UpdateOptions.ExpandFull | UpdateOptions.AlterDependents);

Console.WriteLine("Processing...");

database.Process(ProcessType.ProcessFull);

Console.WriteLine("Complete");

Console.ReadLine();

}

static DataItem CreateDataItem(DataSourceView dsv, string tableName, string columnName)

{

// Helper function

DataTable dataTable = ((DataSourceView)dsv).Schema.Tables[tableName];

DataColumn dataColumn = dataTable.Columns[columnName];

return new DataItem(tableName, columnName,

OleDbTypeConverter.GetRestrictedOleDbType(dataColumn.DataType));

}

How do you set “(Select All)” as the default for multi-value parameters in Reporting Services?

russch — Mon, 07 May 2007 21:39:00 GMT

The short answer is that you can’t, although there is a workaround. Essentially, “(Select All)” as implemented in Reporting Services simply does this:

if (all parameter values/members are already selected)

{

deselect all values/members

}

else

{

select all values/members

}

You can still get the behavior you want however, assuming that your parameter values are query-based. If you populate your parameter list with a dataset, just use the same dataset to set your default values. This technique will work regardless of whether you’re dealing with SQL or SSAS.

In the attached example RDL the “technique” is demonstrated for both a SQL and SSAS-based data source. (You’ll need the AdventureWorks database and cube samples installed)

MDX Script Performance Analyser on CodePlex

russch — Wed, 25 Apr 2007 15:39:00 GMT

I forgot about this one - Chris "Master Chief of MDX" Webb is among the contributors to the MDX Script Performance Analyzer:

"...The MDX Script Performance Analyser allows the user to identify how much each calculated member, named set and scoped assignment in an Analysis Services cube's MDX script contributes to the overall performance of a given MDX query..."

http://www.codeplex.com/mdxscriptperf

SQL Analysis Services Load Simulator released on CodePlex

russch — Fri, 20 Apr 2007 22:09:00 GMT

Just a little while ago ASLoadSim was realeased on CodePlex. It "...contains a set of utilities used to generate a query load and test the scalability of Analysis Services server...". Sounds great to me!

Included as part of the distro is an whitepaper around SSAS load testing best practices.

Here's the link!

http://www.codeplex.com/SQLSrvAnalysisSrvcs

SQL 2005 SP2 most likely available this Monday, 2/19

russch — Fri, 16 Feb 2007 17:35:00 GMT

Get ready to download, because SP 2 was declared "ready to ship" last night. The SQL team is hoping to have it ready for public download Monday-morning-ish (PST).