Mike C (11/22/2010)
I'd like to stress a point the author mentioned in passing: this function is UNDOCUMENTED. What does that really mean? Well, to summarize:1) Microsoft does not support the function. If you run into issues in production with this function, the first solution you will probably get is to remove the dependency on this function. Apart from that you're probably pretty much on your own.
2) It could have undesirable side effects. Blocking comes immediately to mind for this function.
3) It may not be available/accessible in the next release. That is, it can be pulled at any time, including major release, minor release, or even service pack. Sp_makewebtask anyone?
You mentioned Paul Randall, Kimberly Tripp and Isaac Kunen in your article, but I've never seen a recommendation from them to use this in production. Every time I've seen them use this it has been to demo one-off troubleshooting. You may want to clarify this before people start asking how they can use this to do things like create their own transaction log monitoring or home-baked custom replication systems in production environments. Nobody wants to waste money on a CSS call only to find out the code they've written using undocumented functionality is not supported.
TRACEY-320982
Mike and Phil's points about these commands being "Undocumented" and unsupported cannot be stressed enough, obviously. But a very popular blogger once said "It's a physical-record locator function! Undocumented and unsupported (obviously), but hey, some of the best features are :-)" -Paul S. Randal
fn_dblog has changed over the different versions of SQL Server, but it also has survived all of the versions to date as well. It also is the basis for many of the third party applications available, so you be the judge.
I've given you some tools that you can use for your exploration, what you do with it is only limited to your knowledge and imagination. If you've got the wherewithal to build a replication system or some other mechanism using it, then by all means do so. But do keep in mind there are risks to such an appoach that can't be ignored.
When questioned about his work to come up with first light bulb, Thomas Edision replied. “I haven't failed, I've found 10,000 ways that don't work”.