func TestIteratorOptions_MergeSorted(t *testing.T) {
opt := influxql.IteratorOptions{}
sorted := opt.MergeSorted()
if !sorted {
t.Error("expected no expression to be sorted, got unsorted")
}
opt.Expr = &influxql.VarRef{}
sorted = opt.MergeSorted()
if !sorted {
t.Error("expected expression with varref to be sorted, got unsorted")
}
opt.Expr = &influxql.Call{}
sorted = opt.MergeSorted()
if sorted {
t.Error("expected expression without varref to be unsorted, got sorted")
}
}
// CreateIterator returns a single combined iterator for the shards.
func (a Shards) CreateIterator(opt influxql.IteratorOptions) (influxql.Iterator, error) {
if influxql.Sources(opt.Sources).HasSystemSource() {
return a.createSystemIterator(opt)
}
// Create iterators for each shard.
// Ensure that they are closed if an error occurs.
itrs := make([]influxql.Iterator, 0, len(a))
if err := func() error {
for _, sh := range a {
itr, err := sh.CreateIterator(opt)
if err != nil {
return err
}
itrs = append(itrs, itr)
}
return nil
}(); err != nil {
influxql.Iterators(itrs).Close()
return nil, err
}
// Merge into a single iterator.
if opt.MergeSorted() {
return influxql.NewSortedMergeIterator(itrs, opt), nil
}
itr := influxql.NewMergeIterator(itrs, opt)
if opt.Expr != nil {
if expr, ok := opt.Expr.(*influxql.Call); ok && expr.Name == "count" {
opt.Expr = &influxql.Call{
Name: "sum",
Args: expr.Args,
}
}
}
return influxql.NewCallIterator(itr, opt), nil
}