Sql-Server

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.

2015-01-09

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.

2015-01-09

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.

2014-12-22

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.

2014-12-22

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.

2014-12-19

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:

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

2014-12-18

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.

2014-12-12

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!

2014-12-10

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.

2014-12-09

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:

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.

2014-12-06