// NewIterator creates a new Iterator for the given source and metric.
func (db *DB) NewIterator(source, metric string) (*Iterator, error) {
var p partition.Partition = nil
i := db.partitionList.NewIterator()
for i.Next() {
val, _ := i.Value()
val.Hold()
if val.HasMetric(source, metric) {
if p != nil {
p.Release()
}
p = val
} else {
val.Release()
}
}
if p == nil {
return nil, errors.New("catena: couldn't find metric for iterator")
}
partitionIter, err := p.NewIterator(source, metric)
p.Release()
if err != nil {
return nil, err
}
return &Iterator{
source: source,
metric: metric,
db: db,
curPartition: p,
Iterator: partitionIter,
}, nil
}
// Reset moves i to the first available timestamp.
func (i *Iterator) Reset() error {
i.Iterator.Close()
var p partition.Partition
partitionListIter := i.db.partitionList.NewIterator()
for partitionListIter.Next() {
val, _ := partitionListIter.Value()
val.Hold()
if val.HasMetric(i.source, i.metric) {
if p != nil {
p.Release()
}
p = val
} else {
val.Release()
}
}
if p == nil {
return errors.New("catena: couldn't find metric for iterator")
}
defer p.Release()
i.curPartition = p
partitionIter, err := p.NewIterator(i.source, i.metric)
if err != nil {
return err
}
i.Iterator = partitionIter
return nil
}
