When Deletes Increase Data Size

Brent Ozar shows a case where indexes can grow in size as you delete data:

Here’s one way that deletes can cause a table to grow:
– The rows were originally written when the database didn’t have Read Committed Snapshot (RCSI), Snapshot Isolation (SI), or Availability Groups (AGs) enabled
– RCSI or SI was enabled, or the database was added into an Availability Group
– During the deletions, a 14-byte timestamp was added to each deleted row to support RCSI/SI/AG reads

Click through for a demo and takeaways.

Related Posts

Finding Windows Version With T-SQL

Jack Vamvas shows us several methods to figure out which version of Windows you have installed from within SQL Server: Method 2 : Use xp_cmdshell – although this does mean enabling xp_cmdshell , which is in many organisations as security violation  exec master..xp_cmdshell 'systeminfo' Click through for several less controversial methods.

Read More

Azure SQL Database and Extended Events

Dave Bland shows how to set up and read an extended event file on Azure SQL Database: This first step when using T-SQL to read Extended Files that are stored in an Azure Storage Account is to create a database credential.  Of course the credential will provide essential security information to connect to the Azure […]

Read More

Categories

March 2019
MTWTFSS
« Feb Apr »
 123
45678910
11121314151617
18192021222324
25262728293031