This is just one of the ways to quickly reduce the size of the logs. Not the greatest, but very simple and effective. Also, keep in mind that when you truncate SQL transaction logs by this guide, all previous backups made in the Full Recovery model can be discarded. In the training courses, Microsoft recommends that only the Full mode should be used for productive databases.
However, many advanced administrators deliberately set up Simple recovery mode for their databases. In this case, there is a significant increase in performance for mass insert operations and when working with large binary data, which justifies some decrease in the possibilities of backup and recovery.
What is more important for your task — additional recovery options or maximum performance, so decide for yourself. I thank you so much for this! Awesome article and thanks to you bros!! Very nice information and clearly explained. I cleared around GB from the server, which is occupied by log files. Thank you!
Never tell people to auto-shrink database files, this will kill your performance. There have been some misconceptions on the processes behind when the transaction log gets truncated on the primary replica I was confused myself in the good-old-days of database mirroring.
Paul Randal Twitter blog pointed out the ambiguity in the post and provided a great definition for when the transaction log gets truncated on the primary replica:. There are several side effects that you can take away from this definition, all of which you should really pay attention to. The last item is one that you should really pay attention to. So they are either hardware with lower specifications than the primary replica or are virtual machines running on a physical host with lots of other virtual machines.
This causes the REDO portion of crash recovery to take longer because of slower resources on the secondary. Of course, this assumes that you are only running your Availability Groups secondary replicas as a hot standby for high availability purposes. But what about if you are using your Availability Groups secondary replicas for read-only workloads?
The redo information is needed for recovery. The transaction log of SQL Server is comparable with the rollback segment plus the redo logs and archive logs of other database products.
If a transaction log is full, the SQL Server comes to a standstill. When the Full Recovery Model is enabled, transaction log backups must be performed regularly. After each backup, the log is automatically truncated. This frees space in the transaction log without changing the size of the log files.
It must always be present in the database in case the server fails because it will be required to recover the database when the server is restarted. The record at the start of the active portion of the log is identified by the minimum recovery log sequence number MinLSN. The recovery model chosen for a database determines how much of the transaction log in front of the active portion must be retained in the database. Although the log records in front of the MinLSN play no role in recovering active transactions, they are required to roll forward modifications when using log backups to restore a database to the point of failure.
If you lose a database for some reason, you can recover the data by restoring the last database backup, and then restoring every log backup since the database backup. This means that the sequence of log backups must contain every log record that was written since the database backup. When you are maintaining a sequence of transaction log backups, no log record can be truncated until after it has been written to a log backup. The log records before the MinLSN are only needed to maintain a sequence of transaction log backups.
Log truncation always occurs on a checkpoint in tempdb. The part of the logical log before the MinLSN cannot be truncated until those log records have been copied to a log backup. For more information about the interval between automatic checkpoints, see Checkpoints and the Active Portion of the Log..
Transaction logs are divided internally into sections called virtual log files.
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