I just rebuilt the index in the latest beta by issuing a rebuild index command.
The log reports:
2011-01-19 12:53:45.5444 13 Info LibraryIndex Finished indexing resources (in 02:15:28.9118636); writing postings.
but the writing postings part continues for a good four hours after the fact. Indexing may be faster than I remember it, but is this behavior consistent with before? I seem to remember that postings and everything finished up pretty much as soon as the log reported that indexing was finished.