If it overflows, it increases crash count instead. So really you have 2^47
transactions or 65536 crashes and 2^31 transactions between each crash.
it seems to me that you only need to be able to represent a range of the
most recent 65536 crashes... and could have an online process which goes
about "refreshing" old objects to move them forward to the most recent
crash state. as long as you know the minimm on-disk crash count you can
use it as an offset.
-dean-
p.s. i could see a network device with spotty connectivity causing a large
bump in crash count in a short period of time.