I'm not sure what SQL statements you're trying to log. You can trace specific database transactions through various methods. PRPC tracer gives you the option in the later 6 series and it's available in Pega 7. I believe you can also run database traces from inside PAL. Also, long running SQL statements are logged in the alert log. Can you explain more about what sort of context you want to be logging your trips to the database? An average Pega Platform flow will have a number of them to collect things like rules to run, objects to perform work on, etc, so you wouldn't want to be logging everything at all times.
I wonder if we are referring to two different global db trace tools. The one I am referring to is accessible from the System Management Application (SMA) under "Logging and Tracing - > Global DB Trace Management". /Eric