I've devoted the last few blog entries to describing what's in that spatial index analysis proc output and how to use it and interpret the results. Just wanted to describe the rest of the information and how the information relates to what you'd find in a query plan that uses a spatial index. The procs […]

A little more about the query sample that gets fed into the spatial index procs. Query sample is a singleton geometry or geography. It's not a query. So it's not as straightforward as "here's a spatial query that could use an index, run this query and show me the figures". So this procedure is not […]

Last post discussed the filters. The procs report some raw numbers and some derived numbers. Here's a cheat sheet, although the info is all in the BOL. N = Number of rows in the table O = Number of rows output P = Number of rows selected by primary filter (by the index) S = […]

The spatial index diagnostic procs' most enlightening pieces of information have to do with the filter counts and efficiencies reported at the end of the set of columns or XML document output. But what are these filters exactly and what do the results mean? The proc output refers to three filters: 1. Primary Filter 2. […]

I've been looking at the spatial index stored procedures (sp_help_spatial_geography_index_xml and friends) a little harder recently, in an attempt to help answer two questions. 1. If I have a spatial query, why does/doesn't it use my spatial index? 2. If I have a specific spatial query in mind, what are the best values to choose […]