Transaction log

Prashanth Jayaram

How to continuously read Transaction log file data directly in a SQL Server database with fn_dblog and fn_dump_dblog

August 23, 2018 by

Outline

In this article, we’ll discuss how to read SQL Server transaction logs. This article should provide and insight into how the workload is being captured in the transaction log files. We are going to see how to get the transaction meta-data details and the history of the data will give us a clear idea of how the system is working and helps to decide peak usage hours, also helps to log information about who is doing what?

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Prashanth Jayaram

How to set up a DDL and DML SQL Server database transactional replication solution

August 22, 2018 by

In the article How to setup SQL Server database replication for reporting Server we discussed all about setting up a simple SQL Server transactional replication environment. In this article, we’ll simulate a more robust system that replicates faster and includes both DDL and DML statements. We’ll walk-through the steps to setup a dynamic transactional replication.

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Prashanth Jayaram

SQL Server database migrations with zero data loss and zero downtime

August 15, 2018 by

The growing importance and complexity of data migration, in an era of exploding data volumes and ever-changing business requirements, means that old approaches will no longer get the job done. We are in a world where everything needs to run instantly. Every Database Administrator or Developer would have definitely heard about database migrations with zero downtime and with zero data loss.

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Prashanth Jayaram

Using transactional data replication to replay and test production loads on a staging server

August 9, 2018 by

Outline

In this article, you’ll see how to simulate production loads on a test server with a “record and replay” type situation using the transaction log, batch scripting, PowerShell and a SQL Server agent job.

We’ll be walking through the scenario in the following steps

  1. Record the production load and write the transactions to disk by generating a timestamped replay script
  2. Create a batch file to automate the task at an interval of every 1 minute
  3. Create a SQL Server agent job to schedule the batch file
  4. Replay the production workload to the target/test database by running a PowerShell script to open and execute the scripts at the same interval as they were created, every 1 minute
  5. Validate the data between the source and the target databases to make sure our job works
  6. Monitor the load with a monitoring tool, solution of your choice
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Nesha Maric

Reading the transaction log in SQL Server – from hacks to solutions

July 3, 2018 by

The SQL Server transaction log is akin to a ‘Black box’ in an airliner. It contains all of the records of transactions made against a database. This information is a proverbial goldmine for database audits, recoveries etc but it was never meant to be exposed to end users let alone visualized in an easy to read manner nor used for DBA tasks. As such, utilizing this information can be a challenge, to say the least.

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Prashanth Jayaram

How to set up SQL Server Log Shipping on Linux

November 13, 2017 by

Log shipping is a high-availability configuration that perhaps most of us are familiar with. It’s one of the oldest techniques wherein we ship transaction logs from a Primary database to a Secondary database. Log Shipping is still a vital feature used in case of applications that use warm standby for Disaster Recovery. We can see many articles which discuss the process of configuring Log shipping using T-SQL or SSMS.

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What is the SQL Server Virtual Log file and how to monitor it

April 26, 2017 by

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.

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Jefferson Elias

How to take advantage of the SQL Server’s transaction log?

April 11, 2016 by

Introduction

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.

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Timothy Smith

Understanding the distribution scale of transactional and snapshot replication

January 25, 2016 by

Background

If an environment chooses to use snapshot or transactional replication, one useful exercise is to ask the technical end user (or client) what they think replication does. If you have access to a white board, you can even ask them to demonstrate what they think replication will do for their data. Generally, these technical end users will plot something similar to the below image, where we see a table with data being copied to another table with data.

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Miroslav Dimitrov

SQL Server Transactional Replication Moving Distribution Database – step-by-step guide

November 27, 2015 by

SQL Server replication is a relatively old high-availability solution part of the Microsoft world. In fact, there have not been any significant changes to this solution in the recent versions SQL versions, but it is still a widespread mechanism for distributing objects from one database to another and synchronize them. Replication is very useful when you have remote and mobile users accessing your data. Let’s cut to the chase and give you more details about our specific case. 🙂

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Miroslav Dimitrov

SQL Server Transaction Log – Part 3 – Configuration Best Practices

May 4, 2015 by

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.

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Minette Steynberg

Reading the SQL Server Transaction Log

February 9, 2015 by

Introduction

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?
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Miroslav Dimitrov

SQL Server Transaction Log – Part 1 – Log Structure and Write-Ahead Logging (WAL) Algorithm

December 18, 2014 by

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.

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Ivan Stankovic

What is SQL Server log shipping?

March 16, 2014 by

What is SQL Server log shipping?

SQL Server log shipping is a technique which involves two or more SQL Server instances and copying of a transaction log file from one SQL Server instance to another. The process of transferring the transaction log files and restoring is automated across the SQL Servers. As the process result there are two copies of the data on two separate locations Read more »
Ivan Stankovic

Top 10 articles on the SQL Server transaction log

February 13, 2014 by

Understanding Logging and Recovery in SQL Server

In “Understanding Logging and Recovery in SQL Server”, Paul S. Randal has given a complete overview of the transaction log. In four sections he explains: what is logging, what is recovery, how the transaction log works, and which recovery models are available. This article can be used as a starting point in understanding fundamentals of the transaction log and the logging process Read more »
Ivan Stankovic

A beginner’s guide to SQL Server transaction logs

February 11, 2014 by

What is a transaction log?

A transaction log is a file – integral part of every SQL Server database. It contains log records produced during the logging process in a SQL Server database. The transaction log is the most important component of a SQL Server database when it comes to the disaster recovery – however, it must be uncorrupted. After each database modification – transaction occurrence, a log record is written to the transaction log. All the changes are written sequentially Read more »