SQL Server, Again info about statistics and the "Ascending Key Problem"
Hi Guys! Here the post of today i wrote in one go. So don't care about the punctuation, please. In the last post we talked about Cardinality Estimation with a short introduction to the statistics. Before moving forward i would like to tell you some words about how they work and expecially about a problem that can arise with them called the "Ascending Key Problem" So, are you ready for another deep dive? GO! Statistics and Automatic update of statistics. I will try to explain an important concept through the example below. Suppose to have an already populated table (called listofdata) with statistics up to date. The structure of our table is: Create table listofdata (id integer, data datetime, value float) Create index idx_listodata_data on listofdata(data) Watching associated statistics for the index we see that we have 1000 rows each with the same value in the field data. dbcc show_statistics (listofdata, 'idx_listo...