* What happens if the saving child gets killed or segfaults instead of ending normally? Handle this.
* Make sinterstore / unionstore / sdiffstore returning the cardinality of the resulting set.
* check 'server.dirty' everywere
* What happens if the saving child gets killed or segfaults instead of ending normally? Handle this.
* Make sinterstore / unionstore / sdiffstore returning the cardinality of the resulting set.
* check 'server.dirty' everywere