On 11/15/09 11:07 PM, Heikki Linnakangas wrote:
> - When replaying b-tree deletions, we currently wait out/cancel all
> running (read-only) transactions. We take the ultra-conservative stance
> because we don't know how recent the tuples being deleted are. If we
> could store a better estimate for latestRemovedXid in the WAL record, we
> could make that less conservative.
Simon was explaining this issue here at JPUGCon; now that I understand
it, this specific issue seems like the worst usability issue in HS now.Bad enough to kill its usefulness for users, or
evenour ability to get
useful testing data; in an OLTP production database with several hundred
inserts per second it would result in pretty much never being able to
get any query which takes longer than a few seconds to complete on the
slave.
--Josh Berkus