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Day: March 30, 2016

Monitoring SSAS Using Profiler

Published 2016-03-30 by Kevin Feasel

Chris Webb has part 2 of his SSAS multi-dimensional monitoring series:

What’s clear from these examples is that trying to relate what’s going on in the query to what you see in Profiler is quite tricky even for seemingly simple queries; for most real-world queries it would be almost impossible to do so with total confidence. That said, when I’m tuning queries I usually comment out large parts of the code to try to isolate problems, thus creating much simpler queries, and I hope the value of this post will lie in you being able to spot similar patterns in Profiler to the ones I show here when you do the same thing. In part 3 of this series I’ll show you some practical examples of how all this information can help you tune your own queries.

Whenever I read Profiler, my next question is “Is there an extended event which covers this?”

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Securing Plaintext Passwords

Published 2016-03-30 by Kevin Feasel

John Morehouse shows you how to fix plaintext password storage when you can’t fix the application:

Once the data has been encrypted, we can move forward with creating a new view that will be used to “head fake” the application. The view is named the same as the original table therefore the change is seamless to the application.  The application doesn’t know if it’s calling a table or a view so that’s why this works.

You should never store passwords in plaintext.  You should almost never store passwords in a reversable format (i.e., encrypted).  The primary case in which I can see storing passwords encrypted rather hashed is if you have automated systems (or non-automated technicians) which need passwords to authenticate somewhere.  Even then, there’s a lot of value in using OAuth tokens.  But if you can’t get around any of this, John’s solution does remove the really bad decision of leaving passwords in plaintext.

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Availability Groups And VMs

Published 2016-03-30 by Kevin Feasel

John Martin looks at combining Availability Groups with a virtualized environment:

Much of the time there is a systems team and a DBA team, and when the DBAs need to build out a new set of SQL Servers, they request X number of virtual servers from the systems team. The servers are handed over and the DBA team works its magic, and then we have our Failover Cluster Instance or Availability Group High Availability solution. But, is it really Highly Available?

The reason I ask is twofold:

  • Which physical hosts are your Virtual Machines are located on?
  • Which data stores are your virtual disks are located in?

If the answer to either of these questions results in the same answer for any of your Virtual Machines in an Availability Group, or Failover Cluster Instance for that matter. Then you potentially have a massive flaw in your implementation that can affect availability.

The moral of the story is to communicate with the network administrators and SAN folks.

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Service Broker Architecture

Published 2016-03-30 by Kevin Feasel

Colleen Morrow gives explanations for various Service Broker components:

Before I jump into the technical details of the Service Broker architecture, I think it helps to have a real-world analogy of what Service Broker is and does.  In the last installment, I used the example of ordering something from Amazon.com.  This time, I’d like to use an analogy that’s somewhat timely: taxes.

Each year, we fill out that 1040 or 1040EZ form and we send it to the Internal Revenue Service.  Maybe we eFile, maybe we mail it in, it doesn’t matter.  That form is received by the IRS and goes into a queue, awaiting review.  At some point, days, maybe weeks later, our tax return is processed.  If all goes well, our return is approved and the IRS cuts us a check.  That is a Service Broker application.

When I first started learning Service Broker, it seemed like there were a lot of abstract notions (mostly because I didn’t know anything about message queues).  The pieces all start to come together once you get into an application.

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SSRS 2016 Modes

Published 2016-03-30 by Kevin Feasel

John White shows that the Sharepoint Integrated vs Native mode has shifted in SQL Server 2016:

This situation remained exactly the same in SQL Server 2014, but has changed dramatically with SQL Server 2016. SSRS in SQL Server 2016 contains significant advancements, chief among them are a new HTML5 rendering engine, a new report portal, mobile reports, and (soon) Power BI Desktop rendering. This is fantastic news, but it also changes the game significantly with respect to the Integrated/Native mode decision. With SSRS 2016, most of the new investments are in Native mode only – the balance has shifted. The table below shows an (incomplete) list of new features, and their supported modes.

You still need Integrated mode to read Power View reports, and John mentions a few places where Native mode falls short, so take the time to plan out which is right for you.

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Clearing The Azure Procedure Cache

Published 2016-03-30 by Kevin Feasel

Tim Radney shows us a new way of clearing the procedure cache in Azure SQL Databases (and in 2016 RC0 or later):

It turns out that DBCC FREEPROCCACHE is not supported in Azure SQL Database. This was troubling to me, what if I’m in production and have some bad plans and want to clear the procedure cache like I can with the box version. A little Google/Bing research lead me to find the Microsoft article, “Understanding the Procedure Cache on SQL Azure,” which states:

SQL Azure currently doesn’t support DBCC FREEPROCCACHE (Transact-SQL), so you cannot manually remove an execution plan from the cache.  However, if you make changes to the table or view referenced by the query (ALTER TABLE and ALTER VIEW) the plan will be removed from the cache.

In discussing this with Kimberly Tripp after not seeing that described behavior, it does not flush the plan from cache, but it does invalidate the plan (and then the plan will be eventually aged out of the cache). While this is helpful in certain situations, this was not what I needed. For my demo I wanted to reset the counters in sys.dm_exec_cached_plans. Generating a new plan would not give me the desired results. I reached out to my team and Glenn Berry told me to try the following script:

Read on for the new command, and just like DBCC FREEPROCCACHE, be careful where you point that thing.

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