Indexing

Understanding CRUD Operations on Tables with B-tree Indexes, Page-splits, and Fragmentation

  • Article

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 […]

5 (6)

2021-05-10

3,044 reads

Indexes: When Column Selectivity Is Not Always A Requirement

  • Article

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 […]

5 (1)

2020-09-16

2,383 reads

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