How to read and interpret the SQL Server log
When a transaction is being committed, each step is written into the transaction log. Each value that is being inserted, updated, or deleted is recorded so that if there is a failure before the log is written to the data file, the appropriate rollback or roll forward can take place. The transaction may take and release locks on tables or indexes. To view the entries in the log there is an undocumented fn_dblog command . The SQL Server transaction log contains the history of every action that modified anything in the database. Reading the log is often the last resort when investigating how certain changes occurred. It is one of the main forensic tools at your disposal when trying to identify the author of an unwanted change. Understanding the log and digging through it for information is pretty hard core and definitely not for the faint of heart. And the fact that the output of ::fn_dblog can easily go into millions of rows does not help either. But I’ll try to giv...
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