Understand Virtual Log Files in SQL Server Transaction Log File

Virtual Log Files (VLFs) What is VLFs? The SQL Server Database Engine divides each physical log file internally into a number of virtual log files. Virtual log files have no fixed size, and there is no fixed number of virtual log files for a physical log file. The Database Engine chooses the size of the … Continue reading Understand Virtual Log Files in SQL Server Transaction Log File

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KEY-LOOKUP Deadlock in SQL Server

Today, I'm going to talk about a special deadlock case, which is called KEY-LOOKUP deadlock. This deadlock can happen if there are many sessions which are reading or updating on the same row at the same time. We don't distinguish  kind of lock modes (Share / Exclusive), if a lock is existed, other locks must wait until … Continue reading KEY-LOOKUP Deadlock in SQL Server