When are temp tables created in TempDB?

If you want to get to grips with Microsoft’s SQL Server and make full use of all the features it offers, while also optimizing your database as much as possible, you will need to learn to wrangle TempDB.

You probably already know that TempDB is the database that is used to house transient data on a temporary basis, as the name suggests. As such, it is integral to the smooth operation of any server running on this software.

But what are the conditions in which temp tables are created within TempDB? Here is a quick look at the circumstances that cause this to occur.

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Main types of table generation

In most instances, the temp tables that appear in TempDB originate from a need to complete a given process and ensure that the requests which are made of the database are dealt with efficiently.

These tables can be thought of as internal objects since they effectively come into existence automatically as a result of the queries which are being fielded within the SQL Server ecosystem.

The second group of temp tables is those which are created as a result of external influences exerted upon the database, whether in the form of a specific user or a distinct application. Temp tables of this kind only persist for as long as the user is connected to the database; once they drop off, the table will also be terminated.

There are also global temp tables that are designed to persist a little longer than the duration of a single process or individual user session. These are demarcated by a double hash symbol preceding their name, which is a convenience that can help when monitoring performance and attempting to troubleshoot any issues with temp tables in SQL Server.

Complications to watch out for

So long as temp tables behave as expected and are created and dropped in line with internal and external requirements placed upon the server, they should be actively beneficial to performance rather than a hindrance.

However, it is possible for hiccups to occur, although it is rare for the temp tables themselves to be directly at fault.

For example, if the data pages that track the allocation of available storage and other server resources are overburdened, the server’s ability to meet demands for table creation and allocation can increase user wait times when especially high volumes of queries are inbound.

Temp tables can also monopolize storage in their own right, and if the number of active tables spikes when more are being created than are being dropped, contention may arise.

Of course, in spite of the potential issues which can be pinpointed through temp table creation conundrums, it is worth remembering that the use of TempDB itself is undeniably integral to SQL Server. Ultimately it is necessary to track and monitor this and all other aspects of the database’s operations to identify problems as soon as possible and take steps to rectify them without a delay.