Benefits Of Deprecated Data Types

Raul Gonzalez shows how to get one of the benefits of older, deprecated data types using (MAX) data types:

We can see that our table is managed by two different allocation units, IN_ROW_DATA and LOB_DATA, which means that all data within columns of the data types above, will end up in different pages by default, regardless of the size of the data.

This is the default behaviour for old LOB types, to be stored separately, but new LOB types (MAX) by default will try to get them In-Row if they are small enough to fit.

Having some of those documents In-Row will result in a serious increase in the number of pages to scan, therefore affecting performance.

Note that for the table scan we have used only the IN_ROW_DATA pages, making it much lighter than if we have to scan the sum of all pages.

This might be helpful for some situations, like where you rarely need to get to the LOB data.

Related Posts

VARCHAR Size And Memory Grant Estimates

Arthur Daniels shows us a good reason for using better data sizes than just VARCHAR(MAX) everywhere: That’s a lot of desired memory, 1,493,120 KB aka 1.4 GB, but there was only 25 MB used in the sort. So why was SQL Server so far off the right estimate? It’s the data types we picked. That’s a […]

Read More

Valid WAITFOR Data Types

Dave Mason investigates the valid data types you can use as inputs for WAITFOR: There are certain design patterns in T-SQL that give me pause. They may not be “code smells” per se, but when I encounter them I find myself thinking “there’s got to be a more sensible way to accomplish this”. WAITFOR DELAY is one […]

Read More

Categories

April 2017
MTWTFSS
« Mar May »
 12
3456789
10111213141516
17181920212223
24252627282930