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Editorial Team
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Asked: 2026-06-06T18:58:01+00:00

I’m trying to find locations within some distance from given coordinates. On a table

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I’m trying to find locations within some distance from given coordinates. On a table with about 32k records query takes about 2 seconds – which is way too slow, imo.

It is doing a clustered index scan, which is logical – it has to calculate distance for every location.. However, I still think this should be faster over a data set this small. I do have spatial index defined, however it’s not used, and query fails if I’m forcing it.

Most of the time (~86%) is spent on Filter that calculates the distance – so I’m looking for a ways to optimize that, and I need some help here..

The query I’m using is this:

SELECT Name
FROM Venue
WHERE (Coordinates.STDistance(geography::STPointFromText('POINT(-113.512245 51.498212)', 4326)) / 1000) <= 100
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1 Answer

  1. Editorial Team

    One old approach is to use a BOX firxt.

    From your point, make two points on opposite ends of the box. +R/+R and -R/-R from the center.

    Then you can filter – a point has to be in this box AND in the circle you describe.

    The box check can run on the index and kills most elements.

    Simple school geometry. You draw a rectangular box around the circle you describe.

    Your current approach can not use the index because the index does not contain the fields.

    ALTERNATIVELY: DRAW A CIRCLE – do not use a distance calculation. Draw a circle. With points.

    Or read https://stackoverflow.com/questions/11311363/my-application-is-about-asp-net-using-linq-and-remote-mssql-my-connection-is-be which is the same issue you ask.

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