Hi Igor, Excuse my very late answering, it's only today I returned from vacation and could sit in front of a computer to study your problem. Igor R escribió:

Hello,

I've got the following data structure:

[...]

I try to extract all the events belonging to some service and bounded by "period":

namespace bl=boost::lambda; pair<Cache::type::iterator, Cache::type::iterator> byPeriod = cache_.get<Cache::time_tag>().range(bl::_1 >= make_tuple(servicePtr, period.begin()), bl::_1 <= make_tuple(servicePtr, period.last()));

The cache contains lots of matching events, but for some reason, this expression always returs empty region, i.e. byPeriod.first==byPeriod.second.

As far as I can see your expression is correct and should work as you intend. I've written a small complete program that simulates your scenario and everything works fine (see attached file). Maybe you can have a look a it and check for similarities/differences with your code. Rereading your question, I realize that the first key of your composite key compares ServicePtrs, which is not the same as comparing the pointed to Services. Maybe your problem is related to this? Joaquín M López Muñoz Telefónica, Investigación y Desarrollo #include <boost/multi_index_container.hpp> #include <boost/multi_index/ordered_index.hpp> #include <boost/multi_index/composite_key.hpp> #include <boost/multi_index/mem_fun.hpp> #include <boost/lambda/lambda.hpp> #include <boost/shared_ptr.hpp> #include <iostream> using boost::shared_ptr; namespace mi=boost::multi_index; namespace pt{typedef unsigned ptime;} struct Service{}; typedef shared_ptr<Service> ServicePtr; struct Event { ServicePtr service() const{return service_;} unsigned time() const{return time_;} Event(const ServicePtr& service_,unsigned time_): service_(service_),time_(time_){} private: ServicePtr service_; unsigned time_; }; typedef shared_ptr<Event> EventPtr; struct Cache { struct time_tag{}; typedef mi::multi_index_container< EventPtr, mi::indexed_by< mi::ordered_non_unique< mi::tag<time_tag>, mi::composite_key< EventPtr, mi::const_mem_fun<Event, ServicePtr, &Event::service>, mi::const_mem_fun<Event, pt::ptime, &Event::time> > > > > type; typedef type::index<time_tag>::type ByTime; }; int main() { Cache::type cache_; ServicePtr servicePtr=ServicePtr(new Service); ServicePtr servicePtr2=ServicePtr(new Service); unsigned period_begin=0; unsigned period_last=1; cache_.insert(EventPtr(new Event(servicePtr,0))); cache_.insert(EventPtr(new Event(servicePtr,1))); cache_.insert(EventPtr(new Event(servicePtr,2))); cache_.insert(EventPtr(new Event(servicePtr2,0))); namespace bl=boost::lambda; using std::pair; pair<Cache::type::iterator, Cache::type::iterator> byPeriod = cache_.get<Cache::time_tag>().range(bl::_1 >= make_tuple(servicePtr, period_begin), bl::_1 <= make_tuple(servicePtr, period_last)); for(;byPeriod.first!=byPeriod.second;++byPeriod.first){ std::cout<<(*byPeriod.first)->service()<<" "<<(*byPeriod.first)->time()<<std::endl; } }