SQLSentry - a possible gotcha for high-transaction boxes

Blogging it here for my own edification.

We ran into a problem last year where our performance on a box, monitored by SQLSentry, sucked. 

With the help of SQLSentry Support, we were able to find the problem.  Our code uses lots of functions, and their default statement-level trace slowed things down quite a bit - on one box, parsing was cut by 50%.

Note that this is NOT an inherent problem with SQLSentry, but with the level of detail they were collecting via the trace.

(More here: http://sqlblog.com/blogs/linchi_shea/comments/14682.aspx)

From their support (paraphrased and edited for clarity):

The easiest way to test if this helps in your case is just to turn it off and observe.

To disable it, you can go to View-> Settings, then change "Computer Settings" to "SQL Server Settings" , then change "SQL Server Connection" to "Top SQL Settings". [on SQLSentry 8, it's "Top SQL Source"]
 
Now, set "Collect Statement Events" to False.You will probably need to change "Inherit From Parent (Global)" to False in "Collection Settings", otherwise it won't let you change the value.  Finally, click on another server in the left-side drop down (which changes context) to make sure it's saved.  

" What you will be losing here is really just the statement level detail for cached plans that SQL Sentry is collecting. It is nice to have that level of detail, but also not an absolute necessity."

SQLSentry - new feature in 7 (7.1?) that old customers need to know about

So, we lost our SQL Sentry database server last week - thing took a dive.  And, oddly enough, we didn't get a notification from SQL Sentry, even though the database server was being monitored.

Grrrr.

However, from talking with their tech support (who, honestly, are pretty awesome), there's a new notification that can be enabled, that fixes that.  It's not on by default (though I told them they need to change that), so you SHOULD enable it.  

In the Navigator Pane, go to Shared Groups (Global)
Open Failsafe Actions (on mine, it's a tab on the right side of the app)
Add "Monitoring Service: SQL Sentry Database Offline", Send Email
Add "Monitoring Service: SQL Sentry Database Online", Send Email

It also seems like they've improved the way the monitoring services work these days - it was scary easy to add a secondary site that uses our main SQL Sentry database, but monitors only servers at that site.  It's also really easy to add a backup/load-balancing monitoring service in general - install the service on another box, point it at your main SQL Sentry database, and away you go.

May my pain be your gain.