func (s *server) ExecuteQuery(q *protocol.QueryRequest) ([]*protocol.Triple, error) {
var triples []*protocol.Triple
switch q.Type {
case protocol.BASIC:
for i, step := range q.Steps {
if i != 0 {
var midTriples []*protocol.Triple
for _, triple := range triples {
midTriples = append(midTriples, &protocol.Triple{
Subj: triple.Obj,
})
}
step = &protocol.ArrayOp{
Arguments: []*protocol.ArrayOp{step},
Mode: protocol.AND,
Triples: midTriples,
}
}
// External request and is already sharded.
if q.Sharded {
return s.ts.QueryArrayOp(step, int(q.Limit))
}
var wg sync.WaitGroup
var triplesLock sync.RWMutex
triples = nil
shards := query.ShardQueryByHash(step)
// Unrooted queries
if arrayOp, ok := shards[0]; ok {
// TODO localnode
set := s.network.MinimumCoveringPeers()
s.Printf("Minimum covering set %+v", set)
_ = arrayOp
wg.Add(len(set))
req := basicReq(arrayOp)
var err error
for _, conn := range set {
conn := conn
go func() {
var msg *protocol.Message
msg, err = conn.Request(req)
if err != nil {
return
}
triplesLock.Lock()
// TODO(d4l3k): Deduplicate triples
triples = append(triples, msg.GetQueryResponse().Triples...)
triplesLock.Unlock()
done := make(chan bool, 1)
go func() {
wg.Done()
done <- true
}()
go func() {
time.Sleep(10 * time.Second)
done <- true
}()
<-done
}()
}
wg.Wait()
return triples, err
}
// Rooted queries
for hash, arrayOp := range shards {
if hash == 0 {
return nil, query.ErrUnRooted
}
if s.network.LocalPeer().Keyspace.Includes(hash) {
trips, err := s.ts.QueryArrayOp(arrayOp, int(q.Limit))
if err != nil {
return nil, err
}
triples = append(triples, trips...)
continue
}
Peers:
for _, conn := range s.network.Peers {
if conn == nil || conn.Peer == nil {
continue
}
if conn.Peer.Keyspace.Includes(hash) {
req := basicReq(arrayOp)
// TODO(d4l3k) Parallelize
msg, err := conn.Request(req)
if err != nil {
return nil, err
}
triples = append(triples, msg.GetQueryResponse().Triples...)
break Peers
}
}
}
}
//case protocol.GREMLIN:
//case protocol.MQL:
default:
return nil, query.ErrNotImplemented
}
return triples, nil
}
