Troubleshooting SQL Server: A Guide for the Accidental DBA

Jonathan Kehayias and Ted Krueger

Available now from Amazon.com.

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We spend much of our working life helping solve SQL Server-related performance problems, hands-on, during consulting, or on online forums. We’ve seen a few weird-and-wonderful issues but, mainly, it’s the same problems and misconceptions time-and-again. This is our attempt to describe, diagnose, and solve the most common problems with SQL Server 2005, 2008, and 2008 R2.

First, we explain a basic approach to troubleshooting, the essential tools, and how rare it is that a problem can be diagnosed by looking at a single data point. The art of troubleshooting SQL Server is the art of first gathering various pieces of information and then assembling the “puzzle” to reveal a complete picture of what is going on inside a server, and so the root of the problem. Next, we explore the areas in which problems arise with alarming regularity:

• High Disk I/O -RAID misconfiguration, inadequate I/O throughput, poor workload distribution, SAN issues, disk partition misalignment and more
• High CPU usage -insufficient memory, poorly written queries, inadequate indexing, inappropriate configuration option settings, and so on
• Memory mismanagement – the advent of 64-bit SQL Server removes the memory allocation “shackles” placed on its 32-bit predecessors, but issues arising from incorrect memory configuration are still common
• Missing indexes – arguably the number one cause of wasteful resource usage in SQL Server
• Blocking – caused mainly by poorly designed databases that lack proper keys and indexing, and applications that apply needlessly restrictive transaction isolation levels
• Deadlocking – covering the Bookmark Lookup deadlock, the Serializable Range Scan deadlock, the Cascading Constraint deadlock and more
• Full transaction logs – lack of log backups, hefty index maintenance operations, long running transaction, problems with replication and mirroring environments, and more.
• Accidentally-lost data – “oops, wrong database!” Let’s hope you’ve got backups%hellip;

In each case, the book describes the most common problems, why they occur, and how they can be diagnosed using tools such as the Performance Monitor, Dynamic Management Views, server-side tracing, and more. Finally, it provides practical solutions for removing root causes, rather than “papering over the cracks”.

The steps and techniques described are ones we use day-to-day to troubleshoot real SQL Server performance problems. With them, we hope you can solve performance problems quickly and accurately, and tame your unruly SQL Servers.