Can you give a quick explanation on how to get stethoscope or tomograph to capture data? The online documentation is a bit sparse. As I understand it, I can start stethoscope with the following command: "stethoscope -d tpch -h localhost +ts algebra.* bat.* group.* sql.* aggr.*" It does seem to start, but it never seems to progress. I see the following line: "-- opened UDP profile stream StephenMorgan:50010 for localhost" But I never get any more output. As apparently suggested, I ran a query in another window, but got no obvious trace events or any other output. I eventually just killed it with ^C, at which point it said, "-- connection with server localhost closed". It didn't seem to leave behind a file. I also tried running tomograph, using "tomograph -d tpch -h localhost" and got a similar startup message. I ran a query in another window, but nothing happened. When I finally interrupted it, it told me to "Run: 'gnuplot tomograph.gpl'". Aha! Success: however, when I tried that command, it complained that it was "Skipping data file with no valid points". Clearly, I'm missing how to capture data. Thanks, Steve Morgan