RDBMS Doomed?

Here is a great article from Read Write Web that discusses the place and uses for a Key/Value database such as SSDS or SimpleDB or Google App Engine.  Jason Massie argues that the DBA profession will level off in 5-7 years and then start to fall off in 10 because of the prevelence of cloud based Key/Value based databases.

During the last couple of releases of SQL Server, Microsoft has been focused on BI.  Why?  Everyone has lots of data.  Everyone knows that there is a lot of value in that data, but they need to get at it.  BI is one of the top agenda items for CIOs according to Gartner.

What does this have to do with SSDS and SimpleDB?

SSDS and SimpleDB have basically no reporting or analytics capabilities.  Microsoft has mentioned that the future for SSDS includes OLAP like capabilities.  Even if this was available today and shipped today, would companies be ready to move their entire data ecosystem to Microsoft, Amazon, or Google, re-write everything out of RDBMS and into Key/Value programming, then re-work ETL and data warhouse infrasturcture to work on a non-existant (so far, Microsoft says) architecture?

They sure aren’t going to move all of the OLTP systems they have to the cloud right now because the data is then trapped in a no-reporting storage mechanism.  Google App Engine only allows 1000 result objects per query.  Amazon only allows 5 second duration queries.  Can companies’ appetite for analytics be satiated by that?  I don’t think so.

This seems a very log way off.  Even if one of these Key/Value databases HAD reporting and analytics, it seems a minimum of 5 to 7 year for any sizable amount of migration to take place.  And this would be if there WERE analytics and reporting.  There aren’t.

Many companies have large amounts of data and money in their VSAM/COBOL systems that are still running fine that everyone said would have to have been replaced a decade ago.  Those systems aren’t going anywhere for quite a while and these systems need analytics.  These analytics will need to be done on-sight on RDBMS/OLAP platforms.

I suppose for a San Francisco-based startup-focused DBA, there might be a noticible movement to the cloud, but for the rest of the world, it is going to take longer than 5 years to notice a plateau in the need for RDBMS DBAs.

I will however conceede that at some point, there will be a draw to the cloud.  But there are many hurdles to overcome before that can happen in earnest.

One change might be a cloud hosted RDBMS.  Certainly there are some out there somewhere, but the hot topic right now is Key/Value and how that enables large distributed systems.  For a company looking to save money, a hosted RDBMS makes sense, but probably not SSDS and Key/Value.

Float Data Types

This is a really big distinction but is only mentioned in passing in BOL (check here), but approximate numerics are just that:  approximate.  Someone who understands the storage engine better can explain why a foat or real can’t store an exact number, but they can’t and don’t.  You might put 1.5 into it and later come to find that the value is 1.4999.

If you need an exact representation of a number that isn’t an integer, you need to use numeric or decimal.  These are functionally the same, so it doesn’t matter which you choose.

SELECT 1 VS Select *

Connor Cunningham has a great explanation of the difference between using SELECT 1 versus SELECT * in an EXISTS clause.  I’d like to add that I’m assuming that the same rule would apply to SELECT count(*) and SELECT count(1).

SQL Query Optimizer would expand * into the column list and then figure out that none of them are needed.  So theoretically, SELECT count(1) would be a little faster in putting the plan together, but would run at the same speed and have the same IOs as SELECT count(*).

Top Few per Group – Using T-SQL

Ever needed to get the most recent 2 transactions for every customer in a list using a T-SQL statement?  This sounds like an easy task, but upon further examination the query is a little harder than it seems.  One solution, a very ugly solution I might add, would be to cursor through all the customers and run a select statement with an order by clause to get the most recent transactions.  I bet there are other possible solutions, but they all seem to take multiple passes.  A lot of people hate continued posts, but this one is kind of long so I’m going to do just that.  Sorry for the click-through.  I’m not making money on ad pageviews! 

Katmai (SQL 2008) IntelliSense

I wanted to put up a sample of what IntelliSense looks like it Katmai:

(Click on the image for full size)

This is a feature that we have all been hearing about and has finally arrived with Katmai.

I can see how this is going to be very helpful for developer productivity since developers will be prompted with the names of databases, tables, and columns without having to use the Object Explorer.

By the way – I’m using Windows Live Writer to compose this post.  I used it in the first version and this new version is very nice.  I think I’ll be using it from now on.  It facilitates creating more complex and better looking posts.  Very cool.