The logging of the compact task is done in the log.nsf under Miscellaneous Events. It looks something like this (at least in our log.nsf

):
13.07.2008 13.05.59 Compacting Dach081/d081doc.nsf (DACH081 Dokumente)
13.07.2008 13.06.02 Compacted Dach081/d081doc.nsf, 12288K bytes recovered (18%)
13.07.2008 13.06.02 Compacting Dach086/d086doc.nsf (DACH086 Dokumente)
13.07.2008 13.06.15 Compacted Dach086/d086doc.nsf, 0K bytes recovered (0%)
13.07.2008 13.06.15 Compacting Dach098/d098doc.nsf (DACH098 Dokumente)
13.07.2008 13.06.17 Compacted Dach098/d098doc.nsf, 0K bytes recovered (0%)
13.07.2008 13.06.17 Compacting Dach101/d101doc.nsf (DACH101 Dokumente)
13.07.2008 13.06.46 Compacted Dach101/d101doc.nsf, 2304K bytes recovered (0%)
13.07.2008 13.06.46 Compacting Dach105/d105doc.nsf (DACH105 Dokumente)
If you cannot find it there please check the log-level for the server - it might be that it is set in a way that these transactions are not written there.
Hope this helps..
