I would like to share some interesting parameters I found for the undocumented extended stored procedure xp_ReadErrorLog. In doing some testing with this extended stored procedure I found four very interesting parameters. Adding to some of the articles already on the web that discuss undocumented stored procedures, in this article I will explain my testing, use and some examples of the procedure.

ApexSQL is launching a new product called Enforce.  As part of their launch they are giving away twenty-five copies to our members for participating in the forums.  Read on for the details and to find out if you've already won.

One of the more obscure requirements that a developer may find themselves facing is the need to compare a row with its immediate sibling. One such case is when a list of values needs to be processed to produce a moving average or to smooth a sequence of statistical numbers where their order is important.  For example, values lying along a time line. The solution is actually quite simple, but not immediately obvious.

SQL Server 2008 introduces a TIME data type which allows us to store the time without the date.

When designing a database, we sometimes come across situations where there are multiple types of entities that we are modeling, but we'd like them to all have certain attributes or relations in common. Using "sub-type" tables is a simple way to implement table inheritance in SQL Server.

Occasionally someone will ask for my help with a query and say that both a right outer join and a left outer join was tried, and still the expected results were not achieved. That made me realize that some developers do not completely understand outer joins and that an article explaining how to use them might help.

Troubleshooting SQL Server requires the use of both PerfMon (Performance/System Monitor) and SQL Trace files created by SQL Profiler or directly by SQL Server trace. Analysis of the gathered data is much easier if you can correlate your trace file with the PerfMon counters. In this article I'll show how to create a PerfMon counters log file and SQL Profiler Trace file, how to read them both and how to correlate the two files in SQL Profiler.

Or should I place my database files on SAN or directly-attached storage? This is a frequently asked question. It comes up repeatedly in public newsgroups, email discussion lists, and private meetings with customers who are concerned with database performance.

One of the new features found in SQL Server 2005 is the ability to add additional columns, called Included Columns, to a non-clustered index. This article will explain the advantages of using included columns and what impact they will have on your database.

We've arranged for Kalen Delaney to present Controlling and Reusing Query Plans in Kansas City on March 26th, 2008. This full-day seminar will cover techniques available for determining if, when and how you should override the optimizer's choice of query plans. It will also cover how to determine if your plans are being reused, how you can determine if reuse is desirable for your queries, and how you can control query caching behavior. You can get early-bird pricing through February 10th. Please see our corporate site for more information.

Application locks aren't a well known area of locking in SQL Server, but they can be very useful for special scenarios. They work in an analogous way to the lock() construct in .Net and are basicaly user defined mutexes in SQL Server.

Backing up a database is one of the most important things you need to do when having a database driven application. It's only all of your data in there, right? But often developers and management don't realize the importance of backups and overall proper backup strategy for the most important side of the business – data and it's consistency.