func (s *S) TestPrefetching(c *C) {
session, err := mgo.Mongo("localhost:40001")
c.Assert(err, IsNil)
defer session.Close()
coll := session.DB("mydb").C("mycoll")
docs := make([]interface{}, 200)
for i := 0; i != 200; i++ {
docs[i] = M{"n": i}
}
coll.Insert(docs...)
// Same test three times. Once with prefetching via query, then with the
// default prefetching, and a third time tweaking the default settings in
// the session.
for testi := 0; testi != 3; testi++ {
mgo.ResetStats()
var iter *mgo.Iter
var nextn int
switch testi {
case 0: // First, using query methods.
iter, err = coll.Find(M{}).Prefetch(0.27).Batch(100).Iter()
c.Assert(err, IsNil)
nextn = 73
case 1: // Then, the default session value.
session.SetBatch(100)
iter, err = coll.Find(M{}).Iter()
c.Assert(err, IsNil)
nextn = 75
case 2: // Then, tweaking the session value.
session.SetBatch(100)
session.SetPrefetch(0.27)
iter, err = coll.Find(M{}).Iter()
c.Assert(err, IsNil)
nextn = 73
}
result := struct{ N int }{}
for i := 0; i != nextn; i++ {
iter.Next(&result)
}
stats := mgo.GetStats()
c.Assert(stats.ReceivedDocs, Equals, 100)
iter.Next(&result)
// Ping the database just to wait for the fetch above
// to get delivered.
session.Run("ping", M{}) // XXX Should support nil here.
stats = mgo.GetStats()
c.Assert(stats.ReceivedDocs, Equals, 201) // 200 + the ping result
}
}
func (t *Task) returnArray(it *mgo.Iter, proj *entity.Project) (ret []*entity.Task, err error) {
var dt *data.Task
ret = make([]*entity.Task, 0)
dt = &data.Task{}
for it.Next(&dt) {
ret = append(ret, &entity.Task{dt.Id, dt.Title, dt.Description, dt.Done, proj})
}
// in case of any error while fetching the results
// set this to the return
err = it.Err()
return
}