Checking program code into source control is a daily ritual for most developers, but versioning database code is less well-understood. Grant Fritchey argues that getting your databases under source control is not only vital for the stability of development and deployment, but it will make your life easier when something does go wrong.… Read more
What happens if your database deployment goes awry? Do you restore from a backup or snapshot and lose all the data changes that have happened since then? Do you prepare rollback scripts to revert the changes whilst preserving the data? Do you branch by abstraction and toggle off the changes? Have you a blue-green deployment that can be switched? Do you quickly roll forward? … Read more
Although many professions, such as pilots, surgeons and IT administrators, require judgement and skill, they also require the ability to do many repeated standard procedures in a consistent and methodical manner. These procedures leave little room for creativity since they must be done right, and in the right order. For DBAs, standardization involves providing and following checklists, notes and instructions so that the results are predictable, correct and easy to maintain… Read more
Source control will allow you to maintain branches in the development of your database, but the subsequent merge isn't pain-free. How, from the practical perspective, can the database developer support the rapid development and delivery of features in an application? Versioning, branching and merging is part of the solution, but what about the rest of the solution?… Read more
A SQL migration script is similar to a SQL build script, except that it changes a database from one version to another, rather than builds it from scratch. Although they're simple in essence, it is worth knowing how to use them effectively for stress-free database updates and deployments. It takes care to get them right, but it is worth the trouble.… Read more
It is important to set up SQL Server Agent Security on the principles of 'executing with minimum privileges', and ensure that errors are properly logged and alerts are set up for a comprehensive range of errors. SQL Server Agent allows fine-grained control of every job step that should allow tasks to be run entirely safely even if they occasionally need special privileges.… Read more
Although many of the important tasks a DBA has to perform should be done 'by hand', keying in commands or using SSMS, the canny DBA with a heavy workload will always have an eye to automating routine tasks wherever possible, or using a tool. Although the likely candidates for automation are often obvious, it is not always so. Time can often be saved in surprising ways.… Read more
As a DBA, it is vital to manage transaction log growth explicitly, rather than let SQL Server auto-growth events "manage" it for you. If you undersize the log, and then let SQL Server auto-grow it in small increments, you'll end up with a very fragmented log. Examples in the article, extracted from SQL Server Transaction Log Management by Tony Davis and Gail Shaw, demonstrate how this can have a significant impact on the performance of any SQL Server operations that need to read the log.… Read more
This article is an extract from the book Tribal SQL. In this article, Kevin Feasel explains SQL injection attacks, how to defend against them, and how to keep your Chief Information Security Officer from appearing on the nightly news.… Read more
Continuous Delivery is fairly generally understood to be an effective way of tackling the problems of software delivery and deployment by making build, integration and delivery into a routine. The way that databases fit into the Continuous Delivery story has been less-well defined. Phil Factor explains why he's an enthusiast for databases being full participants, and suggests practical ways of doing so. … Read more
Originally one of the articles in the first DBA Team series, Grant wonders what Raymond Chandler or Dashiell Hammett would have done if asked to write technical articles for Simple-Talk. He came up with the DBA detective, hard-boiled Joe Dee Beay… Read more
SQL Server's AlwaysOn Availability Groups provide a very resilient way of providing High-availability for SQL Server databases, but there are inevitable limits to their capacity. How many databases can you reasonably add? It depends on the resources available and the workload, but you can come up with a reasonable estimate as Warwick Rudd explains… Read more
There are more than ten useful command-line applications that are either associated with, or are distributed with, SQL Server. Some, like BCP are used often, whereas others like LogDumper, almost never. However, they
all have their uses and several become important as part of script-based automation of tasks. It is definitely worth knowing what is lurking in your tools\binn directory.… Read more
All DBAs need to engage in a little project management to help make sure everything runs smoothly. In this extract from the book Tribal SQL, David Tate explains his system for managing workload, coleagues, and projects, and how not to be just "the guy who says no".… Read more
A Hyper-V replica will provide a rapid disaster-recovery by simply replicating to a standby site a VM running at the primary site. Is it, therefore, ideal for running SQL Server in high-availability? Well, it depends on the type of HA you require, and whether you need the features that aren't supported. Nirmal explains the details and shows how to set it up.… Read more
If you have a number of SQL Server instances with versions ranging from 2005 upwards, with a whole host of databases, and you want to be alerted about a number of diverse events that are useful for first-line problem-diagnosis and auditing, then Feodor's homebrew solution, using SSIS and Robocopy is likely to be what you're looking for.… Read more
If, before deployment, you need to push the limits of your disk subsystem in order to determine whether the hardware's I/O capacity meets the needs of a database application, if you need performance baselines, or if you want to identify any performance-related issues, then why not use the sqlio utility?… Read more
DBAs regularly need to keep an eye on the error logs of all their SQL Servers, and the event logs of the host servers as well. When server numbers get large, the traditional Windows GUI approach breaks down, and the PoSH DBA reaches for a PowerShell script to do the leg-work.… Read more
The sqliosim utility is provided with SQL Server to test the I/O stability and 'correctness' of a server. It doesn't measure performance but simulates the read, write, checkpoint, backup, sort, and read-ahead activities of a typical SQL Server instance under load. It is generally used before installing SQL Server in order to ensure that new hardware can handle your expected loads. Bob Sheldon explains.… Read more
Every DBA needs to know about SQLPSX, the PowerShell module library that is built by DBAs for DBAs, and designed to provide intuitive functions around the SMO objects. It makes the automation of database administration easier across all versions of SQL Server since SQL Server 2000. Laerte Junior, who is one of the developers on the open-source project, describes how to use it.… Read more
