Expert SQL Server Transactions and Locking: Concurrency Internals for SQL Server Practitioners

© Dmitri Korotkevitch 2018

Dmitri KorotkevitchExpert SQL Server Transactions and Lockinghttps://doi.org/10.1007/978-1-4842-3957-5_3

3. Lock Types

Dmitri Korotkevitch¹ 

(1)

Land O Lakes, Florida, USA

 

This chapter will discuss the key concept in SQL Server concurrency—locks. It will provide an overview of the major lock types in SQL Server, explain their compatibility, and, finally, demonstrate how different transaction isolation levels affect the lifetime of the locks in the system.

Major Lock Types

SQL Server uses locking to support the isolation requirements of the transaction. Every lock, in a nutshell, is an in-memory structure managed by a SQL Server component called the lock manager. Each lock structure uses 64 bytes of memory on the 32-bit and ...