Vladan is working on adding slow SQL tracking to Telemetry, part of that has already landed. He recently exposed this information via the about:telemetry addon. We are working out a few remaining issues so we can send this data to our telemetry servers. In the meantime install the addon in your nightly builds (if you are upgrading from an older version, you need to restart Firefox) and check for yourself whether SQL is to blame for pauses in Firefox.
Is there documentation on how to read those reports? How would I know that SQL is to be blamed?
Thanks!