According to the video, photos has become much more popular than expects. To give you some idea of how popular, take a look at these statistics.

• 2,000 photo uploads per second
• 40,000,000 uploads per day
• 1,000,000,000 uploads per month (a billion!)

Now that’s a lot of data. Since they store multiple sizes of the original images, they have about 40 billion, yes billion images stored as of the video shoot.

These images are stored in a vast raised floor data center that looks to be cram packed with racks of 1U servers and storage units. For those network/data center folks….look at the cable management. We should all strive for that level of cleanliness.

The user to developer ratio is something along the lines of 1,000,000 : 1. Haha. Now that’s a user base.

Neat stuff. Have a great weekend.

Blessings to you and yours.

craig@solidq.com
http://learnmicrosoftbi.com

General Design

• SSAS 2005 and 2008 are extremely different from SSAS 2000
• Upgrading from 200 might work on small simple cubes. Not recommended
• In almost all cases, expect to redesign the AS db to take advantage of new features
• For larger project, plan to have a hardware expert available who understands SAN, load balancing, etc…

Design – Data Sources and Data source Views

• DS should us Windows Authentication when connecting to SQL server and then impersonate a domain account created for this purpose
  • Account should have the least privileges possible to get to the data
• For SQL Server use the Microsoft OLE DB Provider for SQL Server or the SQL Server Native Client instead of the .NET Data provider
• In the Data Source View, create a new diagram for each fact table.
  • This helps make each view look like its own star or snowflake schema
• For simple calculations and concatenations, create new named calculations in the DSV

Design – Dimensions

• There are a number of design issues related to dimensions, including
  • Attribute relationships
  • Attribute key columns and name column
  • Multilevel hierarchies and attribute hierarchies
  • Other areas

Attribute Relationships

• Attribute relationships tell the Analysis Services engine how attributed are related so that it can build aggregations and speed queries (First thing you need to do)
• Ensure that attribute relationships are created and created correctly.
  • The visual designer in BIDS 2008 makes this much easier
• Set the RelationshipType to Rigid when possible.

Attribute KeyColumns and NameColumn

• Ensure that the KeyColumns is set to identify unique values
  • For example, a month value of 1 is insufficient if the dimension contains more than a single year
• Set the NameColumn to a column that makes it clear what is being shown
  • For example, instead of just a month value of 1, combine the month and year

Other Dimension Design Issues

• Hide attribute hierarchies for attributes added to multilevel hierarchy
• A dimension should contain no more than one non-aggregatable attribute
• Use numeric key columns
  • Especially important for dimensions with more than 500,000 members
• Parent-child dimensions should not have more thank 500,000 members in the key attribute.
• Specify a dimension as type Time when possible.
  • Needed for some functions to work.

Design – Measure Groups

• Avoid having multiple measure groups with the same granularity and dimensionality
• Set IgnoreUnrelatedDimensions to False when possible to avoid repeating a value for all unrelated members!
  • Big pitfall for those new to Cubes.
• Don’t create a many-to-many relationship if the dimensions or intermediate fact table have more than one million members
  • Alternatives exist, check out Erik Veerman’s blog at http://blogs.solidq.com/EN/Erik

Design – Aggregations

• Rule of thumb. Start with 20% using aggregation wizard.
  • Then log queries during periods of normal activity and use the Usage Based Optimization wizard (UBO) to define better aggregations.
  • 2005 was a bit lacking, fixed in 2008
• Set approximate counts if there is too much data to let the wizard count the rows
• When creating custom aggregations, do not create aggregations below the measure group’s granularity
• Don’t create overlapping aggregations

Funny. He said “Agg”. Of course to me that means “Agriculture” not “Aggregations”. Ha!

So, wonder if they are going to give away some of those button down SSWUG.org shirts. Very nice! 

Design – Partitions (Ugh)

• Enterprise edition only feature.
• Create partitions for larger data sets in order to speed up queries.
• Partition by common usage, such as time
  • Current year, vs. historical
• Partitioning by more than one criteria is acceptable, but ensure fact records do not appear in more than one partition
• Cubes should have no more than 2,000 partitions with a max of 20,000,000 records each (2000 only)
• Partition the relational warehouse fact table the same way as the cube.

Processing

• Tweak the number of parallel tasks on the production server to see if a different value decreases processing time
• Use ProcessData and PRocessIndex instead of ProcessFull to get more consistent processing pattern
  • 3-5% slower but recommended
• Use ASCMD to manipulate and process objects, especially on very large databases
• Use the <Parallel></Parallel> block to process objects in parallel

Server Settings

• If running other apps or multiple instances of SSAS
  • Move Memory/LowMemoryLimit below 75%
  • Move Memory/TotalMemoryLimit below 80%
• Modify CoordinatorExecutionMode to increase parallelism
  • Negative numbers ……******************8

Querying Tips

• Learn how to monitor queries in action
  • See Identifying and Resolving MDX Query Performance Bottlenecks in SQL Server 2005 Analysis Services
• Make sure to understand the ThreadPool/Query settings
• See if data is coming from a cache, an aggregation, or a subcube query
• In high usage scenarios it can be useful to adjust MemoryHeapType
  • Call PSS for support
• Learn how to scale up and scale out

MDX Tips

• Set Non-Empty behavior property on calculations when possible.
  • Be careful can degrade performance
• Explicitly reference cells when possible
• Move simple calculations from calculations to the DSV
• Learn how to use the Scope statement.
  • Makes for easier to read queries where you typically would have lots of IIF.

Summary

• There are many best practices that must be applied during the design phase.
  • Dimensions
  • Measure Groups
  • Data sources and such
  • Processing can be tweaked through parallelism and memory adjustments
  • Querying can be tuned through proper MDX, memory adjustments and partitioning

Thanks to @swynk for the reminder that I can download the slides. So, my next posts should be just notes of things not on the slides. Whew! I can slow down.

Blessings.

Well, take a look at the partner site at vConferenceOnline.com. They’ve got a great setup going. Essentially the pre-tape each session in the studio. That way the quality is controlled and ends up great. (Next one is slated to be in HD). Then they have created an asp based solution (Gotta wonder why ASP?  ) that handles making the appropriate “rooms” available at the appropriate times during the actual virtual conference. All from the comfort of home, the office, the library or even your favorite coffee shop.

This time, they ran 3 rooms simultaneously for the Business Intelligence conference I attended. The format allows the first half of the day to have these sessions running. The second half of the day the re-run the first half of the day. This way you get a chance to see secondary sessions that may have been running at the same time in the morning.

There were actually 4 conferences going on at the same time. A SQL Server, Business Intelligence, .Net Developer and MS Sharepoint were all available. Each conference was a separate registration fee but for the price you cannot beat it.

Well, take a look at the partner site at vConferenceOnline.com. They’ve got a great setup going. Essentially the pre-tape each session in the studio. That way the quality is controlled and ends up great. (Next one is slated to be in HD). Then they have created an asp based solution (Gotta wonder why ASP?  ) that handles making the appropriate “rooms” available at the appropriate times during the actual virtual conference.

The video quality is very good and continues to improve. The content distribution network they are using seems to be quite well suited for such multimedia distribution. Note, you’re going to need some decent bandwidth to get the best quality.

There are set times for exhibitor booth visits which has gone through a great overhaul this time. On demand vendor videos, downloads and of course vendor chat rooms.

Here’s the best part. 3 days for one conference was $100, actually $10 less since I’ve been to the previous two. That’s a BARGAIN when you consider typical conference costs, meals, lodging, travel and more. You certainly do miss out on the personal interaction however they are working on ideas for that. Currently during each presentation, appropriate chat rooms are available for participants and the speaker.

So, yup, I’ll continue to go as long as the quality of the experience and information remains high. Kudos to those who helped put it on.

Kudos Stephen Wynkoop, Chris Shaw and the rest of the gang.