QueryPlan* TokenAwarePolicy::new_query_plan(const std::string& connected_keyspace,
const Request* request,
const TokenMap* token_map,
Request::EncodingCache* cache) {
if (request != NULL) {
switch (request->opcode()) {
{
case CQL_OPCODE_QUERY:
case CQL_OPCODE_EXECUTE:
case CQL_OPCODE_BATCH:
const RoutableRequest* rr = static_cast<const RoutableRequest*>(request);
const std::string& statement_keyspace = rr->keyspace();
const std::string& keyspace = statement_keyspace.empty()
? connected_keyspace : statement_keyspace;
std::string routing_key;
if (rr->get_routing_key(&routing_key, cache) && !keyspace.empty()) {
if (token_map != NULL) {
CopyOnWriteHostVec replicas = token_map->get_replicas(keyspace, routing_key);
if (replicas && !replicas->empty()) {
return new TokenAwareQueryPlan(child_policy_.get(),
child_policy_->new_query_plan(connected_keyspace, request, token_map, cache),
replicas,
index_++);
}
}
}
break;
}
default:
break;
}
}
return child_policy_->new_query_plan(connected_keyspace, request, token_map, cache);
}
// The number of replicas is bounded by replication factor per DC. In practice, the number
// of replicas is fairly small so a linear search should be extremely fast.
static inline bool contains(const CopyOnWriteHostVec& replicas, const Address& address) {
for (HostVec::const_iterator i = replicas->begin(),
end = replicas->end(); i != end; ++i) {
if ((*i)->address() == address) {
return true;
}
}
return false;
}
TokenAwareQueryPlan(LoadBalancingPolicy* child_policy, QueryPlan* child_plan, const CopyOnWriteHostVec& replicas, size_t start_index)
: child_policy_(child_policy)
, child_plan_(child_plan)
, replicas_(replicas)
, index_(start_index)
, remaining_(replicas->size()) {}
RoundRobinQueryPlan(const CopyOnWriteHostVec& hosts, size_t start_index)
: hosts_(hosts)
, index_(start_index)
, remaining_(hosts->size()) { }
// Helper method to prevent copy (Notice: "const CopyOnWriteHostVec&")
static size_t get_hosts_size(const CopyOnWriteHostVec& hosts) {
return hosts->size();
}