The Downside Of Oversizing

Aaron Bertrand shows why you might not want to oversize VARCHAR columns by too much:

Now, whether you go by the old standard or the new one, you do have to support the possibility that someone will use all the characters allowed. Which means you have to use 254 or 320 characters. But what I’ve seen people do is not bother researching the standard at all, and just assume that they need to support 1,000 characters, 4,000 characters, or even beyond.

So let’s take a look at what happens when we have tables with an e-mail address column of varying size, but storing the exact same data:

This is a good argument against automatically using VARCHAR(8000) (much less MAX) when creating columns.

Related Posts

Nested Loops, Hash, Or Merge: Which Is Best?

Grant Fritchey dodges the important questions: First response, also a joke, was the question at the title of this post: What is the preferred operator when joining tables: Hash Match, Nested Loops or Merge? While my immediate response to this question is, yes. Meaning, they’re all preferred, situationally. I decided to expand on that a […]

Read More

Parallelism Strategies For Grouping Operations

Itzik Ben-Gan continues his series on grouping data in SQL Server by looking at how these operations can go parallel: Besides needing to choose between various grouping and aggregation strategies (preordered Stream Aggregate, Sort + Stream Aggregate, Hash Aggregate), SQL Server also needs to choose whether to go with a serial or a parallel plan. […]

Read More

Categories

June 2017
MTWTFSS
« May Jul »
 1234
567891011
12131415161718
19202122232425
2627282930