During a recent Comprehensive Database Performance Health Check, a customer approached us with a common issue – their index rebuilding process was taking an excessive amount of time to complete. As experienced SQL Server consultants, we knew exactly what needed to be done to address this problem.

One of the key factors affecting index rebuild performance is the usage of TempDB. In a previous consulting engagement with the same customer, we had identified and resolved performance issues related to TempDB. With this knowledge, we had an alternative solution in mind to improve their index rebuilding performance – rebuilding the indexes in TempDB.

Enabling the “sort in TempDB” option can significantly enhance index rebuild performance. By default, when indexes are rebuilt, a large amount of buffer memory is utilized for sorting. When the buffer memory is filled up, the index has to use disk space to store the temporary data. However, by enabling the “sort in TempDB” option, the disk pressure is shifted from the database disk to TempDB.

Here is an example script that demonstrates how to rebuild an index in TempDB:

USE [AdventureWorks2014]
GO
ALTER INDEX [AK_Department_Name] ON [HumanResources].[Department] REBUILD PARTITION = ALL WITH (SORT_IN_TEMPDB = ON)
GO

By adding the keyword “WITH (SORT_IN_TEMPDB = ON)” at the end of the index rebuild script, the index will be rebuilt in TempDB.

It is important to note that this method will only improve performance if your TempDB is on a separate disk and adequately optimized. If your TempDB is also struggling with performance issues, you may not see any improvement. Additionally, ensure that there is enough space in TempDB to avoid encountering a different set of problems.

Improving index rebuild performance is crucial for maintaining a well-performing SQL Server environment. By leveraging the power of TempDB and enabling the “sort in TempDB” option, you can significantly reduce the time it takes to rebuild indexes and optimize your database performance.