Monitoring SQL Server Tempdb Usage

Using dynamic management views, you can easily monitor tempdb usage in SQL server. We can take care of your tempdb problems at Skynats with our Server Management Service.

Monitor TempDB Usage In SQL Server

Tempdb is a system database that numerous SQL Server processes utilize to temporarily store data. The information in these tables saves to the SQL Server tempdb database when a user, for instance, creates a temporary table or declares a table variable. The database engine can use the tempdb for several internal tasks concurrently. Hash Joins, CTE, and Triggers are a few of the frequently performed operations on the tempDB database.

Multiple critical roles that could affect the performance of the database engine are handled by Tempdb. The tempdb database starts to grow quickly when the SQL database system is improperly configured, which can cause chaos if the cause is not found.

This article will demonstrate a straightforward technique for monitoring tempDB usage.

Use “sys.dm db file space usage” to monitor

One of the dynamic management views that aids in keeping track of space usage data for the SQL Server database are sys.dm_db_file_space_usage. The view provides data on how much space is being used by the database file. This view's main advantage is that it provides point-in-time data that illustrates current consumption.

The following query will reveal four key details about the tempdb database's space usage.

SELECT (SUM(unallocated_extent_page_count)*1.0/128) AS [Free space(MB)],(SUM(version_store_reserved_page_count)*1.0/128)  AS [Used Space by VersionStore(MB)],(SUM(internal_object_reserved_page_count)*1.0/128)  AS [Used Space by InternalObjects(MB)],(SUM(user_object_reserved_page_count)*1.0/128)  AS [Used Space by UserObjects(MB)]FROM tempdb.sys.dm_db_file_space_usage;

Let's examine the four space uses in greater detail.

Free Space

The amount of free space in the tempdb database is indicated by the unallocated space. The properties of the tempdb database also display this value.

Used Space by VersionStore

We can prevent read and write conflict by using row-versioning isolation levels. The operating strategy in these isolation layers is based on keeping the most recent row version that was previously committed in tempdb. The version_store_reserved_page_count indicates the total number of pages reserved for the version store.

Used Space by Internal Objects

The SQL Server tempdb database is used by SQL Server to perform several internal tasks, including the temporary storage of data during query execution. For instance, when a statement is executed, table spool operators make a copy of the input data and store it in SQL Server tempdb. The following query makes use of the table spool operator, which makes some space available within the tempdb database.

SELECT  TOP 150 SO.AccountNumber FROM
Sales.SalesOrderHeader SO
INNER  JOIN Sales.SalesOrderDetailEnlarged SD
ON SO.ModifiedDate = SD.ModifiedDate

Used Space by UserObjects

Lastly, the user_object_reserved_page_count field displays the number of pages that are reserved when using table variables, temporary tables, and comparable user objects.