Recent Course Review:
Thanks Mike. Absolutely fantastic. Learnt so much. Clearly presented with excellent use of technology to demonstrate the key points. It covered many aspects of SQL Server not just SQL syntax and gave practical demonstrations of every subject covered. Brilliant. – Mr Dave Morgan
Welcome to Advanced SQL Server Transaction Log Analysis.
In this course, we are going to take a deep dive into analyzing the transaction log.
The SQL Server transaction log contains the history of every action that modified anything in the database.
Before data is written or saved on disk a copy or record of that transaction is first written to the transaction log.
This is part of the D in the ACID properties. Recall that D stands for durability and durability is the ACID property which guarantees that transactions that have committed will survive permanently.
For example, if a flight booking reports that a seat has successfully been booked, then the seat will remain booked even if the system crashes.
This process in SQL Server is accomplished by WAL or Write Ahead Logging.
SQL Server uses a write-ahead log (WAL), which guarantees that no data modifications are written to disk before the associated log record is written to disk.
No matter what you’ve read about non-logged operations the truth is that every user transactions that modifies an internal SQL Server object is logged.
In the course we will learn how WAL works for SQL Srever and some internal architecture on how this is accomplished.
Thanks for your interest in Advanced SQL Server Transaction Log Analysis and we will see you in the course.