Isolation tests still falling over routinely - Mailing list pgsql-hackers

The buildfarm is still showing isolation test failures more days than
not, eg
http://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=pika&dt=2011-09-17%2012%3A43%3A11
and I've personally seen such failures when testing with
CLOBBER_CACHE_ALWAYS.  Could we please fix those tests to not have such
fragile timing assumptions?
        regards, tom lane