NESTING_TRANSACTION_FULL latch
TRANSACTION_*, MSQL_TRANSACTION_MANAGER, NESTING_TRANSACTION_FULL, NESTING_TRANSACTION_READONLY

Within this group of latch classes that are used during various transaction-related operations, the TRANSACTION_DISTRIBUTED_MARK latch is unique. It is used when placing markers in the transaction logs to allow for recovery to a named point. There is only one transaction mark latch in any instance of SQL Server 2005. This latch rarely, if ever, encounters contention, and thus there is no need for an extensive description. The source of any contention is also clear, because this latch is used by only a single operation. The other latch classes in this group are used in various transaction contents. 

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