Performance Tuning with SQL Server Dynamic Management Views

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Chapter 4: Transactions
time on our SQL instances as a result of sorting and hashing intermediate results sets
before returning them to an end-user.
An alternative way to eliminate the worktables would be to add a predicate to the name
column, as the code snippet in Listing 4.12 demonstrates.
…
FROM sys.dm_tran_active_transactions DTAT
WHERE DTAT.name 'worktable'
ORDER BY DTAT.transaction_begin_time
Listing 4.12: Eliminating worktables from the results returned by active_transactions.
While information regarding the transaction start time, type and the current state of the
transaction may be valuable, it is rare to query this DMV in isolation, as it provides an
incomplete picture of transactional activity. We cannot tell, for example, the databases on
which these transactions are running, the sessions or users that are running them, or the
statements that comprise each transaction. To retrieve this information, we'll need to join
DMVs via the transaction_id column, as will be demonstrated shortly.
sys.dm_tran_database_transactions
The sys.dm_tran_database_transactions DMV is server-scoped (the name is
deceptive) and provides detailed information about the transactions occurring on your
SQL Server instance. Like the sys.dm_db_tran_active_transactions view, it provides
point-in-time snapshot data, so the results may vary each time the view is queried.
A cursory glance at the available columns may lead one to assume that the data returned
will be similar to that provided by the sys.dm_tran_active_transactions view.
In fact, however, sys.dm_tran_database_transactions provides a much
more granular level of detail about each transaction and gives "physical presence" to a
transaction, in that it returns information about how it is using the transaction log file.