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Greg Low (The Bit Bucket: IDisposable)

Ramblings of Greg Low (SQL Server MVP, MCM and Microsoft RD) - SQL Down Under

  • Update on Options for Learning Chinese: eChineseLearning

    I seem to have quite a crowd of people that asks me how I’m going with learning Chinese whenever they see me. I promised that I would put together some posts on what has/hasn’t worked for me.

    Over the last few years I had spent quite a bit of time trying to get my Mandarin fluency up. I had finished the 5 levels of Rosetta Stone which helped a lot with vocab but I really don’t like what they’ve done with their online “Rosetta Studio” options. They aren’t good value any more and you don’t get enough practice to be worthwhile. What I wanted to do was to get a better vocab and to gain a lot more practice in conversation, as that’s where the real learning happens.

    I’ve tried a wide variety of options. My current top recommendation is:

    eChineseLearning – No idea where I first came across them (probably an online search) but this has been wonderful. This is providing me with a structured 1 on 1 conversational learning environment. Each week, I spend 3 separate sessions of just under an hour, one on one with a teacher from Wuhan (north of Beijing). They have a booking site where available timeslots are shown, both for my primary teacher (Amy) and for alternates if I need to have a class at a time that Amy isn’t available. I was quite wary about signing up for a service like this but I’m so happy I did. Amy is both interesting and interested in my learning, and provides a good structured approach to work towards proficiency.

    I think this is the quickest way to a good level of proficiency. Each lesson, we spend some time in general conversation, then spend a while working on some new words, then spend some time on grammatical issues, and finally spend some time with listening practice. I like the way it is organised and I like the flexibility of the booking. Most other sites I looked at needed you to commit to the same time each week. With my schedule, that wouldn’t work. eChineseLearning allows me to pick times in each week that will work for me. So if I’m travelling, or have family engagements, I can just work around it. You can change it up to 24 hours before each session.

    I could imagine this site being good for anyone that wants to start learning the language (ie: beginner), or who is keen to become more proficient.

    Like all these types of sites, they love referrals. They’d love you to tell them that you heard of them from me. If you do that, both you and I get free extra time. But that’s up to you.

    Either way, if you’ve wondered about learning another language like Mandarin or you have already tried and stalled, you might want to get a feel for it. They have a free trial lesson. You can sign up here: http://www.echineselearning.com/free-trial/index.html 

    Highly recommended!

  • Clustered columnstore index rebuild script–updated

    Recently I published a series of blog posts that provided scripts for rebuilding clustered columnstore indexes.

    Niko Neugebauer sent me a suggested update to the latest version of those scripts and it makes sense. The change will help to filter out row groups that are not compressed and Niko noted that as Microsoft have started to include more objects (like Tombstone values)  into sys.column_store_row_groups in Azure SQLDatabase, he believes that will help to prevent future SQL versions having a problem with the scripts.

    Sounds good so the latest version is shown below. Thanks Niko !

    ----------------------------------------------------------------------

    -- Rebuild clustered columnstore indexes when necessary

    -- Dr Greg Low v2.1

     

    ----------------------------------------------------------------------

    -- rebuild when more than supplied % of rows have been deleted

    -- rebuild when any segments contain more than supplied % deleted rows

    -- rebuild if more than supplied number of segments are empty

    -- rebuild when segments are on average less than the supplied % of

    --     maximum capacity

     

    DECLARE @DeletedTotalRowPercentage int = 10;  

    DECLARE @DeletedSegmentsRowPercentage int = 20;

    DECLARE @EmptySegmentsAllowed int = 0;

    DECLARE @SegmentPotentialFullnessPercentage int = 90;

    ----------------------------------------------------------------------

     

    DECLARE @IndexesToRebuild TABLE (SchemaName sysname,

                                     TableName sysname,

                                     IndexName sysname);

     

    WITH ClusteredColumnstoreIndexes

    AS

    ( SELECT t.object_id AS ObjectID,

             SCHEMA_NAME(t.schema_id) AS SchemaName,

             t.name AS TableName,

             i.name AS IndexName

      FROM sys.indexes AS i

      INNER JOIN sys.tables AS t

      ON i.object_id = t.object_id

      WHERE i.type = 5

    ),

    RowGroups

    AS

    ( SELECT csrg.object_id AS ObjectID,

             csrg.total_rows AS TotalRows,

             csrg.deleted_rows AS DeletedRows,

             csrg.deleted_rows * 100.0 / csrg.total_rows AS DeletedPercentage,

             CASE WHEN csrg.total_rows = csrg.deleted_rows

                  THEN 1 ELSE 0

             END AS IsEmptySegment

      FROM sys.column_store_row_groups AS csrg

      WHERE csrg.state = 3 -- Compressed (Ignoring: 0 - Hidden, 1 - Open, 2 - Closed, 4 - Tombstone)

    ),

    IndexStats

    AS

    ( SELECT cci.ObjectID,

             cci.SchemaName,

             cci.TableName,

             cci.IndexName,

             SUM(CAST(rg.TotalRows AS decimal(18,0))) AS TotalRows,

             SUM(CAST(rg.DeletedRows AS decimal(18,0))) AS DeletedRows,

             SUM(CAST(rg.DeletedRows AS decimal(18,0))) * 100.0

               / SUM(CAST(rg.TotalRows AS decimal(18,0)))

               AS DeletedPercentage,

             SUM(rg.IsEmptySegment) aS EmptySegments,

             COUNT(rg.TotalRows) AS TotalSegments

      FROM ClusteredColumnstoreIndexes AS cci

      INNER JOIN RowGroups AS rg

      ON cci.ObjectID = rg.ObjectID

      GROUP BY cci.ObjectID, cci.SchemaName, cci.TableName, cci.IndexName

    )

    INSERT @IndexesToRebuild (SchemaName, TableName, IndexName)

    SELECT s.SchemaName, s.TableName, s.IndexName

    FROM IndexStats AS s

    WHERE s.DeletedPercentage > @DeletedTotalRowPercentage

    OR s.EmptySegments > @EmptySegmentsAllowed

    OR EXISTS(SELECT 1 FROM RowGroups AS rg

                       WHERE rg.ObjectID = s.ObjectID

                       AND rg.DeletedPercentage > @DeletedSegmentsRowPercentage)

    OR (s.TotalRows * 100 / (s.TotalSegments * 1048576.0))

                < @SegmentPotentialFullnessPercentage;

     

    DECLARE @SchemaName sysname;

    DECLARE @TableName sysname;

    DECLARE @IndexName sysname;

    DECLARE @SqlCommand nvarchar(max);

     

    DECLARE IndexList CURSOR FAST_FORWARD READ_ONLY

    FOR

      SELECT SchemaName, TableName, IndexName

      FROM @IndexesToRebuild

      ORDER BY SchemaName, TableName, IndexName;

     

    OPEN IndexList;

     

    FETCH NEXT FROM IndexList INTO @SchemaName, @TableName, @IndexName;

     

    WHILE @@FETCH_STATUS = 0

    BEGIN

      SET @SqlCommand = N'ALTER INDEX ' + QUOTENAME(@IndexName)

                      + N' ON ' + QUOTENAME(@SchemaName)

                      + N'.' + QUOTENAME(@TableName)

                      + N' REBUILD PARTITION = ALL;';

      PRINT @SqlCommand;

      EXEC(@SqlCommand);

      FETCH NEXT FROM IndexList INTO @SchemaName, @TableName, @IndexName;

    END;

     

    CLOSE IndexList;

    DEALLOCATE IndexList;

     

  • PASS BA Analytics Conference for 2015

    I’m always telling people that the thing I love about BI projects is that they tend to appeal to the people who pay the bills. This is a good place to be doing project work.

    When I look at large companies like Amazon, I can imagine that the people who do the IT work that relates to order processing, invoicing, shipping, etc. do a great job. But I’ll bet that their life is full of budget cutbacks, headcounts, increased pressure to improve productivity, etc. By comparison, I’ll bet the projects that fund parts of their site that make recommendations for possible purchases, etc. are funded at an entirely different level. And that’s because these projects can more directly impact the profitability of the organization, and do so in a more visible way.

    When you stop and look at your career, you might want to consider whether you should be trying to move up the value stack within your organization.

    A great place to get ideas on this would be to attend the PASS BA Analytics Conference. This relatively new conference has a very different focus to the “standard” PASS summit. If analytics interests you at all, this would be the place to be in April:

    And if you provide the registration code UKBA05, you’ll get a $150 discount as well.

  • Improved clustered columnstore index rebuild–potential segment fullness

    Earlier, I posted a maintenance script that could be used with clustered columnstore indexes to try to determine when they should be rebuilt. Reorganize is not a very useful operation for these indexes as it basically just forces a close of the existing delta store, ready for compression.

    One of the problems with a clustered columnstore index is that it doesn’t work as well if the segments have been created at less than the maximum potential size of 1048576 rows per segment. Over use of reorganize options could cause this, but more likely it will be to do with loading the index with small batches of data, rather than loading large batches in BULK INSERT operations.

    I’ve updated the maintenance script so that you can now also choose to rebuild if your segments are much less full than their optimal size ie: you could have 1,048,560,000 rows of data in 10,000 segments. So if you say 90 percent as the cutoff and your segments hold less than 90 percent of their potential, that will also trigger a rebuild.

    Hope this helps someone:

    ----------------------------------------------------------------------

    -- Rebuild clustered columnstore indexes when necessary

    -- Dr Greg Low v2.0

     

    ----------------------------------------------------------------------

    -- rebuild when more than supplied % of rows have been deleted

    -- rebuild when any segments contain more than supplied % deleted rows

    -- rebuild if more than supplied number of segments are empty

    -- rebuild when segments are on average less than the supplied % of

    --     maximum capacity

     

    DECLARE @DeletedTotalRowPercentage int = 10;   

    DECLARE @DeletedSegmentsRowPercentage int = 20;

    DECLARE @EmptySegmentsAllowed int = 0;

    DECLARE @SegmentPotentialFullnessPercentage int = 90;

    ----------------------------------------------------------------------

     

    DECLARE @IndexesToRebuild TABLE (SchemaName sysname,

                                     TableName sysname,

                                     IndexName sysname);

     

    WITH ClusteredColumnstoreIndexes

    AS

    ( SELECT t.object_id AS ObjectID,

             SCHEMA_NAME(t.schema_id) AS SchemaName,

             t.name AS TableName,

             i.name AS IndexName

      FROM sys.indexes AS i

      INNER JOIN sys.tables AS t

      ON i.object_id = t.object_id

      WHERE i.type = 5

    ),

    RowGroups

    AS

    ( SELECT csrg.object_id AS ObjectID,

             csrg.total_rows AS TotalRows,

             csrg.deleted_rows AS DeletedRows,

             csrg.deleted_rows * 100.0 / csrg.total_rows AS DeletedPercentage,

             CASE WHEN csrg.total_rows = csrg.deleted_rows

                  THEN 1 ELSE 0

             END AS IsEmptySegment

      FROM sys.column_store_row_groups AS csrg

    ),

    IndexStats

    AS

    ( SELECT cci.ObjectID,

             cci.SchemaName,

             cci.TableName,

             cci.IndexName,

             SUM(CAST(rg.TotalRows AS decimal(18,0))) AS TotalRows,

             SUM(CAST(rg.DeletedRows AS decimal(18,0))) AS DeletedRows,

             SUM(CAST(rg.DeletedRows AS decimal(18,0))) * 100.0

               / SUM(CAST(rg.TotalRows AS decimal(18,0)))
               AS DeletedPercentage
    ,

             SUM(rg.IsEmptySegment) aS EmptySegments,

             COUNT(rg.TotalRows) AS TotalSegments

      FROM ClusteredColumnstoreIndexes AS cci

      INNER JOIN RowGroups AS rg

      ON cci.ObjectID = rg.ObjectID

      GROUP BY cci.ObjectID, cci.SchemaName, cci.TableName, cci.IndexName

    )

    INSERT @IndexesToRebuild (SchemaName, TableName, IndexName)

    SELECT s.SchemaName, s.TableName, s.IndexName

    FROM IndexStats AS s

    WHERE s.DeletedPercentage > @DeletedTotalRowPercentage

    OR s.EmptySegments > @EmptySegmentsAllowed

    OR EXISTS(SELECT 1 FROM RowGroups AS rg

                       WHERE rg.ObjectID = s.ObjectID

                       AND rg.DeletedPercentage > @DeletedSegmentsRowPercentage)

    OR (s.TotalRows * 100 / (s.TotalSegments * 1048576.0))
                < @SegmentPotentialFullnessPercentage
    ;

     

    DECLARE @SchemaName sysname;

    DECLARE @TableName sysname;

    DECLARE @IndexName sysname;

    DECLARE @SqlCommand nvarchar(max);

     

    DECLARE IndexList CURSOR FAST_FORWARD READ_ONLY

    FOR

      SELECT SchemaName, TableName, IndexName

      FROM @IndexesToRebuild

      ORDER BY SchemaName, TableName, IndexName;

     

    OPEN IndexList;

     

    FETCH NEXT FROM IndexList INTO @SchemaName, @TableName, @IndexName;

     

    WHILE @@FETCH_STATUS = 0

    BEGIN

      SET @SqlCommand = N'ALTER INDEX ' + QUOTENAME(@IndexName)

                      + N' ON ' + QUOTENAME(@SchemaName)

                      + N'.' + QUOTENAME(@TableName)

                      + N' REBUILD PARTITION = ALL;';

      PRINT @SqlCommand;

      EXEC(@SqlCommand); 

      FETCH NEXT FROM IndexList INTO @SchemaName, @TableName, @IndexName;

    END;

     

    CLOSE IndexList;

    DEALLOCATE IndexList;

      

     

  • Demos must work–simple concept? So why is it so rarely applied?

    When I attend events like TechEd, like many people I usually find the networking time more valuable than the session time. There is a pretty tight limit on the number of sessions you can attend, no matter how hard you try. So I often watch the sessions later when I can. At one of the earliest TechEd Australia events that I attended, they gave us CDs of the TechEd USA sessions. That was great because that TechEd had around 250 sessions, and there were over 150 that I would have loved to attend. Clearly that wasn’t possible.

    I was doing a lot of driving to/from client sites at that time, and so I had a lot of available listening time. I dragged the audio out of all the TechEd session videos and just listened to the audio. If a session really interested me, I’d go back and watch the video and demos.

    That year, I listened to/watched around 150 sessions. While it was intense and interesting, there was something that I wasn’t expecting, that completely stunned me. I heard the presenters apologising for demo failures in close to 100 of those sessions. I found that really, really hard to believe. I was determined that when I was presenting any sort of session at events like these, that I wasn’t going to be one of those people, or I’d do my very best to avoid it.

    Having your session work as planned already puts you in the top third of all the sessions.

    So if you want to be on the right side of this equation, what can you do?

    1. Have realistic goals for the amount of content.

    I normally aim to tell people three things in a session. They certainly won’t remember more than that and it’s the stories that they’ll remember anyway, so make sure that each demo has a good story associated with it. And if showing any one of these three things takes more than about 15 to 20 minutes, try again. Blaise Pascal said “I would have written a shorter letter, but I did not have the time”. Plan the content and tell the story succinctly. Plan your timing. It’s hard work to get just the right message in just the right amount of time.

    I have lost count of how many sessions I’ve been to that run out of time or that failed to make one of the key points. Don’t be one of them.

    You’ll be especially sorry if your session description includes content that you didn’t end up covering. Someone might have come just for that content.

    2. Aim for repeatable achievable outcomes.

    I’ve seen so many demos that would probably only ever work with the moon in the correct position and the presenter holding his/her head the right way. Don’t do this.

    3. Have a clear structure.

    There’s perceived wisdom that sessions should be all demos. I don’t buy it as the only rule. I’ve been to brilliant sessions with none, and I’ve been to horrid sessions from amazing people where they have no structure to what they are trying to show.

    4. Practice both the session and the demos.

    And I mean multiple times. The bigger the event, the more the whole session needs to be second nature. Try to deliver the session at smaller venues first. Local user groups, virtual sessions, etc. are good options for this.

    5. Find another presenter as a critical friend.

    I have friends that are talented presenters and I love having one of them in the room for trial runs, with a view of being critical. Someone that says “yeah that was great” is nice. Someone that says “you lost me in the second part of the demo” or “I think the third demo would work better if you…” is what you need. Be prepared to do the same for them.

    6. Record the demos.

    When presenting at large events, I have a series of screen shots saved on a USB key, and I also have a full video walkthrough of each of the demos. I’m determined that the audience will get to see the demos.

    As a simple example of when this has saved me, two years ago for TechEd Australia, I was presenting some Azure-related sessions. The Azure folk had decided to do maintenance and take things offline right in the middle of the event.

    I told the audience, switched across to the videos of each demo, which I did a live voice-over for, and I suspect that many of them would have quickly forgotten that they were watching a video. By comparison, I attended several other Azure-related sessions at that same event and watched presenter after presenter stumbling when things would not work. You need a fall back plan.

    Hint: Don’t just play the video with voice, etc. as well though – make it still pretty much a live thing. I’ve seen sessions where people just play a video with sound and it often looks like they could never have actually done the demo, particularly if it’s someone else’s voice.

    7. Don’t try to debug live.

    Unless it’s an obvious and trivial issue, you will do far more damage by trying to debug it. Attendees hate watching you stuff around trying to fix issues. You might feel great *if* you ever get it solved but you will have messed up your timing and possibly looked really, really bad in the meantime. And if you can’t solve it, you will have really messed up. Instead, move on and use your backup plan.

    Isn’t this what everyone does?

    It seems pretty basic to do these things but time and again, I see the opposite happening even at major events. I watched AzureConf the other day, and even the keynote had these issues. Having been involved in event keynotes and knowing what level of rehearsal normally goes into them, I can just imagine the discussions that went on later. They wouldn’t have been pretty.

    You can avoid being one of these statistics with just a bit of planning, and you’ll already be ahead of the pack.

  • Rebuild clustered columnstore indexes when they require maintenance

    For general index maintenance, our friend Old Hallengren has an awesome solution for most people: https://ola.hallengren.com/sql-server-index-and-statistics-maintenance.html

    We’ve started to have customers using clustered columnstore indexes in SQL Server 2014, and they need to be treated differently. I checked Ola’s latest scripts today to see what happens with columnstore indexes. It appears that the code ignores nonclustered columnstore indexes (ie: index type of 6), which makes sense as we need to rebuild them whenever the data changes, and in the meantime, the table is read-only. So that makes lots of sense.

    For other indexes (including clustered columnstore indexes which are updatable), the code uses the same avg_fragmentation_in_percent values from sys.dm_db_index_physical_stats. Unfortunately, that view doesn’t return any data for columnstore indexes of either type, so that’s not actually helpful.

    Niko has an awesome series of blog posts about columnstore indexes that I encourage you to read: http://www.nikoport.com/columnstore/ In part 36, he discusses what he thinks is needed for maintenance. The metrics that I want to use overlap the ones that he’s suggested in that article.

    With a clustered columnstore index, when a row is deleted, a flag in a bitmap is updated to indicate the deletion. The row is still present in the columnstore row group. When an update occurs, the same mechanism flags the row as deleted, then inserts the new version into the delta store.

    The main problems that will occur are when many rows have been deleted.

    In the code below, I’ve provided an implementation that will rebuild clustered columnstore indexes in a database when one of three criteria is met:

    • The overall percentage of deleted rows has exceeded a cutoff (I’ve suggested a 10% default)
    • The percentage of rows in any individual segment exceeds a cutoff (I’ve suggested a 20% default)
    • The number of segments that are completely empty (all rows have been deleted) has exceeded a cutoff (I’ve suggested none)

    This would work for both COLUMNSTORE and COLUMNSTORE_ARCHIVE compression.

    Hope it helps someone until Ola does his magic:

    ----------------------------------------------------------------------

    -- Rebuild clustered columnstore indexes when necessary

    -- Dr Greg Low v1.0

     

    ----------------------------------------------------------------------

    -- rebuild when more than supplied % of rows have been deleted

    -- rebuild when any segments contain more than supplied % deleted rows

    -- rebuild if more than supplied number of segments are empty

     

    DECLARE @DeletedTotalRowPercentage int = 10;   

    DECLARE @DeletedSegmentsRowPercentage int = 20;

    DECLARE @EmptySegmentsAllowed int = 0;         

    ----------------------------------------------------------------------

     

    DECLARE @IndexesToRebuild TABLE (SchemaName sysname,

                                     TableName sysname,

                                     IndexName sysname);

     

    WITH ClusteredColumnstoreIndexes

    AS

    ( SELECT t.object_id AS ObjectID,

             SCHEMA_NAME(t.schema_id) AS SchemaName,

             t.name AS TableName,

             i.name AS IndexName

      FROM sys.indexes AS i

      INNER JOIN sys.tables AS t

      ON i.object_id = t.object_id

      WHERE i.type = 5

    ),

    RowGroups

    AS

    ( SELECT csrg.object_id AS ObjectID,

             csrg.total_rows AS TotalRows,

             csrg.deleted_rows AS DeletedRows,

             csrg.deleted_rows * 100.0 / csrg.total_rows AS DeletedPercentage,

             CASE WHEN csrg.total_rows = csrg.deleted_rows

                  THEN 1 ELSE 0

             END AS IsEmptySegment

      FROM sys.column_store_row_groups AS csrg

    ),

    IndexStats

    AS

    ( SELECT cci.ObjectID,

             cci.SchemaName,

             cci.TableName,

             cci.IndexName,

             SUM(rg.TotalRows) AS TotalRows,

             SUM(rg.DeletedRows) AS DeletedRows,

             SUM(rg.DeletedRows) * 100.0 / SUM(rg.TotalRows) AS DeletedPercentage,

             SUM(rg.IsEmptySegment) aS EmptySegments

      FROM ClusteredColumnstoreIndexes AS cci

      INNER JOIN RowGroups AS rg

      ON cci.ObjectID = rg.ObjectID

      GROUP BY cci.ObjectID, cci.SchemaName, cci.TableName, cci.IndexName

    )

    INSERT @IndexesToRebuild (SchemaName, TableName, IndexName)

    SELECT s.SchemaName, s.TableName, s.IndexName

    FROM IndexStats AS s

    WHERE s.DeletedPercentage > @DeletedTotalRowPercentage

    OR s.EmptySegments > @EmptySegmentsAllowed

    OR EXISTS(SELECT 1 FROM RowGroups AS rg

                       WHERE rg.ObjectID = s.ObjectID

                       AND rg.DeletedPercentage > @DeletedSegmentsRowPercentage);

     

    DECLARE @SchemaName sysname;

    DECLARE @TableName sysname;

    DECLARE @IndexName sysname;

    DECLARE @SqlCommand nvarchar(max);

     

    DECLARE IndexList CURSOR FAST_FORWARD READ_ONLY

    FOR

      SELECT SchemaName, TableName, IndexName

      FROM @IndexesToRebuild

      ORDER BY SchemaName, TableName, IndexName;

     

    OPEN IndexList;

     

    FETCH NEXT FROM IndexList INTO @SchemaName, @TableName, @IndexName;

     

    WHILE @@FETCH_STATUS = 0

    BEGIN

      SET @SqlCommand = N'ALTER INDEX ' + QUOTENAME(@IndexName)

                      + N' ON ' + QUOTENAME(@SchemaName)

                      + N'.' + QUOTENAME(@TableName)

                      + N' REBUILD PARTITION = ALL;';

      PRINT @SqlCommand;

      EXEC(@SqlCommand); 

      FETCH NEXT FROM IndexList INTO @SchemaName, @TableName, @IndexName;

    END;

     

    CLOSE IndexList;

    DEALLOCATE IndexList;

     

  • Invalid Quorum Configuration Warnings when failing over SQL Server Availability Group

    At a client site today and they asked me about a warning that they got every time they manually failed over their SQL Server availability group.

    It said: “The current WSFC cluster quorum vote configuration is not recommended for the availability group.” They were puzzled by this as they had a valid quorum configuration. In their case, they had a two node cluster using MNS (majority node set) and a fileshare witness.

    The problem with that message is that it is returned when the node voting weight is not visible.

    Windows Server 2008 failover clustering introduced node-based voting but later an option was provided to adjust the voting weight for each node. If the cluster is based on Windows Server 2008 or Windows Server 2008 R2, and KB2494036 has not been applied, even though each node has a vote, the utilities that check voting weight are not supplied a weight value. You can see this by querying:

    SELECT * FROM sys.dm_hadr_cluster_members;

    This will return a row for each cluster member but will have a missing vote weight.

    Applying the KB hotfix will make this DMV return the correct values, and will make this invalid warning disappear.

  • Online certification exams are now available in Australia

    I’ve been hoping this would happen for a while and now it’s here (in beta).

    Whenever I take a certification exam, I find it removes my ability to work for most of a day, so I tend to schedule myself for two or three exams in a day, to avoid the overhead. It also means that I tend to limit the number of exams that I would take.

    Online proctoring of exams changes all that for me. If I can just schedule an exam for lunch time or night, or weekend from my own office, I’ll be much more inclined to take more certification exams.

    There are some rules:

    • You'll be recorded—both video and audio—for the duration of the exam.
    • You can't take notes during the exam.
    • You can't eat, drink, or chew gum while you take the exam.
    • You can't take a break—for any reason.

    They seem reasonable to me and if you don’t like them, you can always attend an in-person exam. Better make sure you get to the rest room beforehand though Smile It’s not available in all countries yet but fortunately Australia is one of the countries in the list. I’m not sure how the countries are chosen because I notice that our Kiwi buddies aren’t in the list yet. I’m sure that will change over time.

    Regardless, this is a really good initiative. Well done Microsoft Learning.

    You’ll find more information here: https://www.microsoft.com/learning/en-us/online-proctored-exams.aspx

  • Telerik Dineissimo Sample App–Interesting Marketing Approach

    I’ve liked the Telerik tools for a long time. I see many of my clients using either their controls for Webforms, and many using KendoUI for newer MVC development. I suppose it’s a challenge for such vendors to work out how to best market their products, but also a challenge to show developers how to best use them.

    With KendoUI, I particularly liked the Kendo Dojo idea, where you could just interactively learn to use the framework directly from inside your own browser without having to install anything locally.

    Today, I’ve noticed they released a sample application called Dineissimo but what caught my eye was the marketing approach. Basically, you need to visit: https://www.telerik.com/campaigns/platform/run-hybrid-app and download the app. You then need to find a particular part of the code, then run the program and use a QR (quick response) code to get things going. Finally, in the app, they get you to edit your profile and add a selfie or other image before sending off the details. And for a bunch of early takers, they’ll send an Amazon gift card. There’s a walk-through here: https://www.telerik.com/campaigns/platform/run-hybrid-app

    I like the fact that they are releasing a bunch of source code to show how to use their product but it’s the marketing approach that interests me. It combines getting genuine interest in the product, making sure it’s actually seen, then getting the user further involved.

    Nice job Telerik.

  • Determining your session’s transaction isolation level

    A question came up from a developer yesterday. He could see how to set a transaction isolation level but didn’t know how to determine the current transaction isolation level. That detail is available in the sys.dm_exec_sessions DMV.

    Here’s an example:

    image

     

    And if you are running SQL Server 2012, you could always use CHOOSE instead:

    image

  • Should there be code differences between Azure SQL Database editions?

    I spend a lot of time working with software houses, helping them to make their applications work well with SQL Server. One thing that I’ve heard loud and clear over the years is that most software houses won’t write a single line of code that will only run on the enterprise edition of SQL Server, because they are not prepared to limit their potential pool of customers to those running enterprise edition.

    This is completely at odds with the discussions that I’ve had with the SQL Server marketing team members who think that having feature differences will cause people to purchase enterprise edition instead. I’m sure that’s true for customers who write their own applications in-house and is also why at promotional events, the customers that you see mentioned are often those types of customers. However, most SQL Server customers run 3rd party applications written by other companies. The customers will often ask the software houses what software is required to run their applications and they then purchase what they need, unless they have some other pre-existing form of relationship with Microsoft.

    So this means that having a difference in features can actually cost Microsoft money as the customers will often purchase standard edition because that’s all the software that they will be running requires.

    Worse, when software houses are comparing SQL Server to other database engines, they compare SQL Server standard edition to the other engines, not the enterprise edition. This makes SQL Server compare badly for marketing reasons instead of technical reasons. For example, I saw a software house the other day comparing SQL Server with PostgreSQL. Their contention was that PostgreSQL (a free database engine) had a good high availability story and that SQL Server did not. Their logic was that SQL Server only had mirroring (and log shipping) and Microsoft had announced the deprecation of mirroring. So their contention was that SQL Server did not have a good availability story. The fact that enterprise edition had a really good story was irrelevant as they don’t consider anything in that version.

    A further issue appears with coding. There is no developer edition of SQL Server that is limited to standard edition features. Software houses want to write code once and have it work across all target editions.

    Another core issue is that this focus on enterprise edition has removed the upgrade reasons for standard edition customers. I think that every edition should have a compelling upgrade story, for every version. As an example, in SQL Server 2014, the reasons to upgrade for standard edition customers are the ability to use 128GB of memory and to have backup encryption. I’ll leave it to the reader to decide if that’s a strong story. I don’t think it is.

    The final issue with the existing situation is that the product is moving into areas that need support from software houses. SQL Server 2014 introduced a range of in-memory options. For any customer that can’t change the code (ie: most customers), this is irrelevant. Again you’ll see the same large customers who write their own apps being mentioned in the launch events. I this case, I think the marketing team really have made a mistake. While new HA features, etc. can be retrofitted by a DBA to an existing database, the new in-memory options really need to be architected into the design of the applications. And that’s where it’s a real problem that it’s in enterprise edition only. The software houses are unlikely to use it, and yet they are exactly the same people that we need to embrace it.

    So what does this have to do with Azure?

    Bob Beauchemin wrote a great blog post today about how Azure SQL Database is moving to a SQL Server 2014 code base. That’s a great thing but one aspect that caught my eye was the mention that this is the first version of Azure SQL Database where features like columnstore indexes, etc. will only appear in the premium editions of Azure SQL Database.

    While I’ve had concerns about how the licensing has been handled in the on-premises versions of SQL Server, in Azure SQL Database this concerns me even more. I really think that Azure SQL Database should offer the same code surface no matter which edition you are using. It makes sense to have performance and availability (including HA) options differ between Basic, Standard, and Premium but I really don’t like the idea of coding/feature differences. First up, it will again see software houses ignoring useful features. But worse, in the Azure SQL Database arena, customers are much more likely to use a mix of database editions than they currently do on-premises.

    For example, if I am offering an application as a service, I want to be able to have different databases for different tenant customers. I really want to be able to choose the performance, reliability, availability options, etc. on a tenant by tenant basis, not across all tenants that are using my application. Having coding differences across the editions would make this a mess, or at least I think so.

    I’d love to hear your thoughts.

  • Office 365 coming to Australian Data Centres

    We’ve been so excited having local data centres for Microsoft Azure.

    The one disappointment has been that Office 365/Power BI has still been based out of Singapore data centres. That has an effect on people that worry about data sovereignty and it also means that we’ve had higher latency on the connections.

    But no more! I was really pleased to read an article in the newspaper yesterday that mentioned that Microsoft is moving Office 365 to the Australian data centres. The article claims this is happening in April next year. I can only hope it’s true as this will be a really good outcome thanks Microsoft!

    Here’s the article: http://www.theaustralian.com.au/business/latest/microsoft-to-deliver-office-365-from-australian-data-centres/story-e6frg90f-1227149621552?nk=41c535e280e2d2c90d15e82eefcb763c

  • DAX Studio 2.0 is out the door

    Learning to write DAX queries is important in the new world of tabular data models. DAX Studio is the best environment right now for learning to write and test DAX queries.

    Today Darren Gosbell announced on his blog that version 2.0 of DAX Studio is out the door. This is a superb effort and one that you should both applaud and use.

    The biggest improvements seem to be around the UI. It looks very impressive but there is much more to it than just the UI.

    image

    DAX Studio can be run standalone (as an exe) or as a ribbon within Excel. Nice!

    If you need to develop and/or run DAX queries, this is now a far superior option than creating them in SQL Server Management Studio.

    Go and download it now from here: http://daxstudio.codeplex.com/

    And also go back to Darren’s blog and leave a note thanking him for the early Christmas present !

  • Microsoft Action Figures–SQL Server and Heroes

    I’ve ended up with a number of Microsoft figurines over the years. It all started with Nine Guy, then went on to the whole Source Force team:

    imageimage

    It’s been interesting to see how they’ve evolved over the years. Here are the SQL Server ones:

    SQL Server 2005 had a demure little lady that was all Red. She morphed into an orange version by SQL Server 2008 (shown here with me at TechEd USA) in 2008. Later she took on a Neo look from the Matrix, and now there’s a guy, the Query Controller.

    image   image

    I love the way that the tradition continues. Microsoft Virtual Academy recent had a Heroes program where you got sent a figurine if you completed one of a specific set of app dev and server courses. (Each course had a number of sub-courses). Here’s the full set:

    image

  • Rett Syndrome Research needs help

    Very proud of my daughters this week. As some of you will know, one of my daughters has Rett syndrome. It's a rare chromosomal disorder that basically only impacts girls. (Boys can get it but they usually do not survive long after birth). Girls develop fairly normally up to about 12 to 18 months of age, then regress markedly. As it affects only about 1 in 10,000 girls, it's not the sort of thing that gets much research funding.

    So my other two daughters have decided to raise some funding to help with a local Rett research program. If anyone is interested, you can make a donation directly here: https://www.mycause.com.au/…/fundraiserforrettsyndromeresea…

    Alternately, my youngest daughter is organising a staged musical for early next year (in Brisbane) with all profits again going directly to the Rett research team. I’ll post more about it closer to when tickets for the musical are available.

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