Microsoft SQL Server has many important features when it comes to file structures. Generally speaking, DBAs often ignore file structures and growth configurations. More specifically, the SQL Server Log files are often left at default values and never touched, even when they begin to cause problems caused. These Log files are important and critical part of the database, especially when it comes to large systems.Read more »
When we’re architecting or troubleshooting issues in an environment, understanding how the log is set up and its history helps us identify if improving it will carry significant impacts overall. We have some built in tools that we can use, such as DBCC LOGINFO and DBCC SQLPERF and in this tip we look at how we can use them when we’re debugging issues, designing our logs for scale, or monitoring our current setup. We also look at some ways we can retain the information these provide so that we can use this for historic measurements and benchmarking, as well as using them for potentially alerting.Read more »
SQL Server databases consist of two physical files types; the data file in which the data and the database objects such as tables and indexes are stored, and the transaction log file in which SQL Server stores records for all transactions performed on that database.Read more »
SQL Server keeps track of all database modifications and every database transaction. This is done in a file called the transaction log or TLOG. This transaction log is particular to a SQL Server database and there is, at least, one transaction log per SQL Server database.
As explained on MSDN, the transaction log is a critical component of the database and, if there is a system failure, the transaction log might be required to bring your database back to a consistent state. The transaction log should never be deleted or moved unless you fully understand the ramifications of doing this.Read more »
It has been a while since the last transaction log article has been published, so I hope you do remember where this series is heading to. In the former posts, we have examined the Log Structure and Write-Ahead Algorithm (part 1) and the Top Reasons for Log Performance Problems (part 2). Taking into consideration this knowledge, we will review some best-practices for transaction log configuration in order to decrease the chance of experiencing log bottlenecks.Read more »
There has always been some debate as to whether or not there are real benefits to be gained from accessing the information in the transaction log. This article will endeavor to answer that question by looking at the following:
- What is the SQL Server Transaction Log?
- What information is stored in the transaction log?
- What can be gained by accessing the information in the transaction log?
- How does the transaction log work?
- What tools are available for reading the transaction log?
- And ultimately, is this something we should be doing at all?
SQL Server transaction log is one of the most critical and in the same time one of the most misinterpreted part. While being neglected, it can easily become a bottleneck to our SQL Server environment. We need to have this in mind and to take care of our transaction logs in order to streamline the performance of our queries and increase log’s throughput.Read more »