26
Mar
10

An interview with Denis Gobo

As part of our continuing series of going through the book, SQL Server MVP Deep Dives we have had the opportunity to ask some of the authors a few questions.  This week we are chatting with Denis Gobo   (LessThanDot – blog,  sqlblog,  Blogspotblog,  @DenisGobo – Twitter).

1.)   In the book SQL Server MVP Deep Dives, why did you choose the two subjects that you chose? (Chapter 8, What makes a bulk insert a minimally logged operation?  Chapter 20, Why every SQL developer needs a tools database)

The reason I picked these two subjects is because of a couple of reasons. In regards to bulk loading, just using bcp or BULK INSERT is not enough there are more things needed to make it truly minimally logged. People in general know about simple or bulk recovery but there is still a large percentage of people that don’t know that you also need to lock the table. In the chapter I wrote I show the difference in the size of the LOG when you lock and don’t lock the table.

In regards to the Tools database, it is because I struggled myself with maintaining code that should live in one place and one place only. There are database I stumbled upon that had the same code in several stored procedures, this code was identical, it was doing some calculation. So you of course already know that sometimes the change was made in 4 instead of 5 procedures and you might not notice for a couple of months, especially if it was end of quarter calculation or worse year end. Having a Tools database simplifies coding, testing and debugging, it really is as simple as that.

 

2.)    Do you have any tips on minimally logged operations for partitioned tables and the switching of partitions therein?

You know I can tell you a small percentage of what you need to know here or I can tell you to read the We Loaded 1TB in 30 Minutes with SSIS, and So Can You whitepaper by Microsoft   which covers way more than I could ever cover in this interview. It is a must read for everyone importing a lot of data.

 

3.)    Has the Tools database that you reference in Chapter 20 ever been a challenge for management or the business to understand / support?  If so, what are a couple of compelling reasons to those that don’t just “get it”?

In general business doesn’t get involved with my databases so I am lucky in that regards. Management definitely sees the value proposition here; think of the reasons why companies purchase/install a framework or a component. They do it because it is cheaper than writing it yourself. A framework will be used by lots of people and tested by lots of people, there is no reason to write/debug/test these things yourself and reinvent the wheel. The same thing is true for a Tools database, it is better that 10 developers use 1 business function instead of each developer having their own flavor of the same function. It is also nice to say to your manager that the code that the other developer needs to write already exists in the Tools database for 2 years and has been tested thoroughly.

 

4.)    To date, what has been your favorite feature / functional aspect of SQL Server, regardless of version?

Partitioned functions, date data type and data compression are three of my favorite things

Up until last year I was still on SQL Server 2000 on some servers and I had partitioned views on those servers. There is a lot more maintenance and correct setup (think check constraints on the partitioned column) required than partitioned functions to get the optimizer to only touch the base tables affected by the WHERE clause. Compression is just a no  brainer especially if you are IO bound, it also saves money in terms of SAN space since your storage needs less space. Dates are a biggie for me because I save 5 bytes per row and if you have multi billion row tables this adds up.

 

5.)    What’s the number one technical deficit that you believe SQL Server professionals need to address?

The biggest problem with SQL Server in my opinion is that there is just too much stuff in the product these days to become proficient in all of them. Just take a look what happened when SQL Server 2000 came out compared to SQL Server 7, we got indexed views, user defined functions and maybe a couple of other things. Now take a look at when SQL Server 2005 came out, wow that was quite a learning curve. There were new tools (SSMS and BIDS), new way of getting metadata with DMVs, Service Broker CLR, SSIS, SSAS etc etc. These days you see more and more specialists, people focus on performance or BI or do only SSIS. Of course now that they added c# to SSIS 2008, there is yet another thing to learn if you need to maintain other peoples work.

In terms of databases itself I think that data about the data (metadata) is virtually nonexistent, how many times have you opened up a database and looked at a table where the names just did not make any sense to you. And there was no documentation except for some comments in some stored proc.

This of course brings up naming convention but that is a whole different can of worms and I won’t even go into that here.

 

6.)    What’s the number one piece of functionality or change that you would like to see in the next version of SQL Server?

Okay, there are things I can and cannot say because I know some of the things that are coming in SQL 11 and I am under NDA for those. Well I can tell you about one thing I would like to see and that is the ability to store a table in columns not rows. This would be especially handy if you could do it against read only partitions and where only the active partition was stored in rows and the rest of the partitions in columns. Here is some made up syntax

ALTER PARTITION Bla

MARK RANGE (…) Active, STORAGE = ROWS

All_OTHER_RANGES, STORAGE = COLUMNS.

Something like that, Gemini on the BI side is using columnar storage already so I can’t see why this can’t make it into a future version. Of course if you do SELECT * then you won’t benefit from columnar storage, ideally you should think of it as one big index with included columns for all the columns in the table.

 

7.)    Where does the SQL Server community at large find you when you’re not at your job?

There are a couple of places I can be found. I participate in the SQL Server programming  forum at LessThanDot, a website I co-founded with a bunch of other people I met in cyber space. I also blog on LessThanDot here: http://blogs.lessthandot.com/index.php/All/?disp=authdir&author=4. You can also find me on twitter @denisgobo.  I answer question on Stackoverflow, here is my profile: http://stackoverflow.com/users/740/sqlmenace. There are some more places online where I am active at but the ones listed are the ones I am most active.

Finally, I will also be at SQL Saturday 39 in New York City on April 24th but I won’t be speaking.

 

8.)    I’ve saved the most important question for last… Does the Query Optimizer respond better to cursing in one language over another?  If so, can you PLEASE share the knowledge?

Ha, this depends on the default collation of course :-)

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