Choosing Between Optimistic Concurrency Levels

Kendra Little has a cheat sheet for comparing the two optimistic concurrency levels:

SQL Server offers two flavors of optimistic locking for traditional disk-based tables: Read Committed Snapshot Isolation (RCSI), and Snapshot Isolation. They are each great tools to reduce blocking and make applications faster, particularly in databases that have lots of tiny reads and writes that need to be quick, or mixed-use patterns (lots of little reads and writes + larger reporting queries).

Both isolation levels are available in SQL Server Standard Edition and Web Edition as well as Enterprise. That’s right, they’re cheap and easy. Each of them are controlled by database level settings, and default to disabled when you install SQL Server.

The moral of the story:  both of these are awesome, both have potential drawbacks, and both need testing.  I’ve had good experiences with RCSI, but even then, maybe about 1% of procedures need specific locking hints (either NOLOCK or an explicit lock) to maintain previous application behavior and to deal with the problem Kendra brought up.  Moral of the story:  test, test, test.

Related Posts

Choosing Clustered Index Columns

Ed Elliott wades into the clustered index debate: I have seen this debated in forums spread over the internet for decades, and the advice that we gave ten years ago isn’t as valid today as it was then. Ten years ago, memory was considerably less, and disks were spinning rust. The advent of SSD’s and […]

Read More

Detecting and Analyzing Deadlocks

Max Vernon has a couple scripts to analyze deadlocks in SQL Server: Deadlock detection and analysis in SQL Server is important for the overall health of affected applications. This post shows how to setup an Extended Events session to capture deadlock details. It also provides a stored procedure to capture details from the Extended Events […]

Read More

Categories

February 2016
MTWTFSS
« Jan Mar »
1234567
891011121314
15161718192021
22232425262728
29