A SQL Server process that periodically scans all SQL Server caches, and maintains the Free List, which is the collection of buffer pages available for immediate re-use. If necessary, the Lazy Writer process writes modified pages out to disk in order to make them available. A high value of lazy writer writes may indicate non-optimal buffer cache memory size or use of inefficient queries.
An object used by a software, such as SQL Server, to indicate that a user has an interest in a resource, and to prevent multiple users accessing the same resource in conflicting ways simultaneously. The simplest example is to prevent two people from updating the same information at the same time.