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Redo Logs for SQL Server

Posted on 2004-10-05
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Last Modified: 2008-03-06
Oracle has Redo Logs for 'Undeleting' records.

What is equivalent in SQL Server?

I need to find any reference to records that were deleted.

Thanks!

RipHerANewOne!
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Question by:RipTide
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by:arbert
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There really isn't  a "direct" counterpart.  SQL Server has the transaction log that (if the recovery mode is setup right) will allow you to do point in time restores to the database.  However, you can't browse the transaction log without a third party tool (logexplorer from lumigent is nice http://www.logexplorer.com)
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EugeneZ earned 75 total points
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Answer: transaction log  
[from http://www.akadia.com/services/sqlsrv2ora.html]

Each SQL Server transaction log has the combined functionality of an Oracle rollback segment and an Oracle online redo log. Each database has its own transaction log that records all changes to the database and is shared by all users of that database. When a transaction begins and a data modification occurs, a BEGIN TRANSACTION event (as well as the modification event) is recorded in the log. This event is used during automatic recovery to determine the starting point of a transaction. As each data modification statement is received, the changes are written to the transaction log prior to being written to the database itself. For more information, see "Transactions, Locking, and Concurrency" later in this paper.

SQL Server has an automatic checkpoint mechanism that ensures completed transactions are regularly written from the SQL Server disk cache to the transaction log file. A checkpoint writes any cached page that has been modified since the last checkpoint to the database. Checkpointing these cached pages, known as dirty pages, onto the database, ensures that all completed transactions are written out to disk. This process shortens the time that it takes to recover from a system failure, such as a power outage. This setting can be changed by modifying the recovery interval setting by using SQL Server Enterprise Manager or with Transact‑SQL (sp_configure system stored procedure).
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by:arbert
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transaction log is not the same thing as a redo log....but it's as close as you get...if the recovery model is set to simple, you won't be able to obtain the same information you would from a redo log....
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