Ever wonder what DUMP_LOG_COORDINATOR_QUEUE wait is?

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If you’ve used wait statistics to do performance tuning on your SQL Server systems, I doubt that you would ever see this on your top waits (or if even shows up at all). You would rarely find anything on the Internet about this wait type, although, I did find a placeholder from SQLServerpedia for future information. However, if you have been heavily playing around with the SQL Server undocumented function fn_dump_dblog(), you may have seen this wait type. This occurs when you run this function to read your log backups. Janice Lee (a schoolmate of mine from way back home) blogged about using this function as an alternative to restoring to a point in time. While I did not use this function to do a point-in-time restore of a database, I did find it interesting seeing the DUMP_LOG_COORDINATOR_QUEUE wait type. I actually used it to estimate the amount of INSERT, UPDATE and DELETE commands executed on my database. While it is not pretty straightforward as compared to gathering performance counters, it’s the only thing I can do especially if you were brought in for a one time consulting engagement and need to work with what you have.

Note that I did not run this in a production server so I have no issues running the undocumented function. Use it at your own risk.