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Working with JSON Indexes in SQL Server 2025

Koen Verbeeck tries out a new index type:

We’re trying the new JSON data type in SQL Server for data stored as JSON in a table. When we query it using functions such as JSON_VALUE, we see a full table scan is performed for each query. Is there a way we can index the JSON to improve performance?

The JSON index has a somewhat different definition of its structure and there are some limitations to how it works, but for specific JSON-related queries, you can see the improvement.

2 Comments

  1. George Walkey
    George Walkey 2025-11-05

    Im seeing only 1.8x speedups using the JSON DataType and JSON Indexes vs ye old VCMax. Will continue testing on RTM+

    • Kevin Feasel
      Kevin Feasel 2025-11-05

      Thanks for the concrete numbers. I’m not sure what to expect with JSON indexing, so it’s good to get some specific examples of how it’s faring in real-world scenarios.

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