Practical Query Tagging in EF Core

Sample query tagging!

What is query tags in EF Core?

It’s introduced in EF Core 2.2. This feature helps correlate LINQ queries in code with generated SQL queries captured in logs. You annotate a LINQ query using the new TagWith() method.

var publishedBlogPosts = dbContext.BlogPosts
    .Where(b => b.PublishedAt != null)
    .TagWith("Getting published blog posts")
    .ToList();

When EF generates the SQL with TagWith method, it also includes the tag as a comment in the query; as a result, debugging and profiling queries might be easier.

-- Getting published blog posts
SELECT [b].[BlogPostId], [b].[Content], [b].[PublishedAt], [b].[Title]
      FROM [BlogPosts] AS [b]
      WHERE [b].[PublishedAt] IS NOT NULL

How to make it more practical?

Debugging and profiling are all about having more information. We can easily access member name, line of code and source file with caller information attributes.

Now take a look to my extension method: