Locking

Dmitry Piliugin

SQL Server NOLOCK and Top Optimization

April 12, 2018 by

Sometimes people use nolock hint as a “turbo” button for their queries, assuming that not taking locks will speed up the query execution. There are many good articles describing all the dangerous moments of this approach, because of the read uncommitted isolation level. However, the focus of this article is a performance problem that you may encounter using nolock hint in some cases.

Let us setup some test data first.

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Ahmad Yaseen

How to control online Index Rebuild Locking using SQL Server 2014 Managed Lock Priority

July 18, 2017 by

When you perform a SQL Server Online Index Rebuild operation, introduced for the first time in SQL Server 2005, the index will not be taken down. But at a specific point, in which the new index new is built and switched from the old structure of the index, a special kind of lock, Schema Modification (SCH-M), will be granted. This lock may cause blocking if your database server is busy.

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Nikola Dimitrijevic

All about locking in SQL Server

June 16, 2017 by

Locking is essential to successful SQL Server transactions processing and it is designed to allow SQL Server to work seamlessly in a multi-user environment. Locking is the way that SQL Server manages transaction concurrency. Essentially, locks are in-memory structures which have owners, types, and the hash of the resource that it should protect. A lock as an in-memory structure is 96 bytes in size.

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