T-SQL

Changing Directions

I See Dead Tech….

Knowing when a technology is dying is always a good skill to have. Like most of my generation we weren’t the first on the computer scene but lived through several of it’s more painful transitions. As a college student I was forced to learn antiquated technologies and languages. I had to take a semester of COBOL. I also had to take two years of assembler for the IBM 390 mainframe and another year of assembler for the x86 focused on the i386 when the Pentium was already on the market. Again and again I’ve been forced to invest time in dying technologies. Well not any More >

The Mystery Of The Slow Last Row

Things Go South

Recently I was troubleshooting a piece of software that archives data out of a very active import table. It is a pretty simple app. It queries the table for any id’s that have data older than X days. It then queries the table again to pull the detail data generating a csv file, table schema script and compresses them for storage. Well, it was running slow. Much slower than expected in fact. It has to process around 5000 id’s and it was taking 50 to 240 seconds an id. This doesn’t sound slow but it adds up in a hurry. I started digging into the code looking at the normal More >

The Dangers of Sub-queries!!!!

Ok, now that I have your attention this really should be titled the danger of not qualifying all objects, but that isn’t quite as sensational enough to make you click through to here

Imagine if you will, a developer expects ten records to be inserted into a table and the query has been running for almost an hour.  A quick glance and sp_who2 shows that it is using a lot of IO, I mean a lot. The first thing that happens is a command decision from the boss to kill the query. I took a quick peek and found the plan still in the plan cache while we waited for this thing to roll back. As I look at More >

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