NOLOCK On CTEs

Erik Darling shows how the NOLOCK hint works with common table expressions:

So, for all you NOLOCKers out there, you can now save yourselves oodles of time by only using the hint in outer references to your CTEs and Views.

Congratulations, I suppose.

(Please stop using NOLOCK.)

Agreed, whenever possible.

Related Posts

When Adding Indexes Hurts Performance

Jeffry Schwartz takes us through an odd case: Recently, a customer requested that we tune a query that took 13 seconds to return 11 rows.  SQL Server 2017 suggested an index to improve performance, so we added it in a development environment.  The improvement made the query run 647 seconds, almost 50 TIMES longer than the original!  This naturally caused […]

Read More

Power Query and the Benefits of Immutability

Chris Webb explains why immutable expressions can be faster to run multiple times than mutable processes: Instead of taking the value #”Sorted Rows”[Column2]{0} and storing it in the variable Column2 then adding Column2 four times, I’m  adding the expression #”Sorted Rows”[Column2]{0} together four times. The query returns the same number as the previous query. However […]

Read More

Categories

March 2017
MTWTFSS
« Feb Apr »
 12345
6789101112
13141516171819
20212223242526
2728293031