Using The YEAR Function

Kendra Little looks at the performance ramifications of using the YEAR() function:

But if we hover over that index seek, we can see in the tooltip that there’s a hidden predicate that is NOT a seek predicate. This is a hidden filter. And because this is SQL Server 2016, we can see “Number of Rows Read” — it had to read 9.3 million rows to count 1.9 million rows. It didn’t realize the 2006 rows were together– it checked all the females and examined the FakeBirthDateStamp column for each row.

Built-in functions can cause SARGability issues.

Related Posts

Query Store Indexes

Arthur Daniels shows what you can learn from the indexes on Query Store tables: It looks like internally Query Store is referred to as plan_persist. That makes sense, thinking about how the Query Store persists query plans to your database’s storage. Let’s take a look at those catalog views vs their clustered and nonclustered indexes. […]

Read More

Gotchas When Indexing Partitioned Tables

Andrew Pruski gives us a couple of considerations when creating indexes on partitioned tables in SQL Server: Looking at that data page, we can see that SQL has added a UNIQUIFIER column. Now this is standard SQL behaviour, SQL does this to all non-unique clustered indexes whether they are on a partitioned table or not. But also […]

Read More


March 2016
« Feb Apr »