In the last year I’ve published articles on indexes to include Indexes: When Column Selectivity Is Not Always A Requirement – SQLServerCentral and Query Optimizer Suggests Wrong Index and Query Plan -- Why? – SQLServerCentral. This article is a continuation of just how the optimizer interacts with the index wizard. We’ve all heard and read […]
Introduction Every DML transaction reads the data before it makes any changes. Not only during a SELECT query, but when you run any DML statement, insert, update, or delete, SQL Server first fetches a bunch of pages into the buffer pool locating the desired rows and changes them while synchronously writing to the transaction log […]
While preparing for my SQL Saturday Salt Lake City presentation, Climbing the B-Tree, I ran into one of the “word of mouth” facts that the first column of an index should be highly selective, i.e., it should only point to one or a few rows. This is not always the case and I’ll show you […]
Today Kendra talks about two of the online options used when working with indexes.