func (self *Shard) executeQueryForSeries(querySpec *parser.QuerySpec, seriesName string, columns []string, processor cluster.QueryProcessor) error {
startTimeBytes := self.byteArrayForTime(querySpec.GetStartTime())
endTimeBytes := self.byteArrayForTime(querySpec.GetEndTime())
fields, err := self.getFieldsForSeries(querySpec.Database(), seriesName, columns)
if err != nil {
// because a db is distributed across the cluster, it's possible we don't have the series indexed here. ignore
switch err := err.(type) {
case FieldLookupError:
log.Debug("Cannot find fields %v", columns)
return nil
default:
log.Error("Error looking up fields for %s: %s", seriesName, err)
return fmt.Errorf("Error looking up fields for %s: %s", seriesName, err)
}
}
fieldCount := len(fields)
rawColumnValues := make([]rawColumnValue, fieldCount, fieldCount)
query := querySpec.SelectQuery()
aliases := query.GetTableAliases(seriesName)
if querySpec.IsSinglePointQuery() {
series, err := self.fetchSinglePoint(querySpec, seriesName, fields)
if err != nil {
log.Error("Error reading a single point: %s", err)
return err
}
if len(series.Points) > 0 {
processor.YieldPoint(series.Name, series.Fields, series.Points[0])
}
return nil
}
fieldNames, iterators := self.getIterators(fields, startTimeBytes, endTimeBytes, query.Ascending)
defer func() {
for _, it := range iterators {
it.Close()
}
}()
seriesOutgoing := &protocol.Series{Name: protocol.String(seriesName), Fields: fieldNames, Points: make([]*protocol.Point, 0, self.pointBatchSize)}
// TODO: clean up, this is super gnarly
// optimize for the case where we're pulling back only a single column or aggregate
buffer := bytes.NewBuffer(nil)
valueBuffer := proto.NewBuffer(nil)
for {
isValid := false
point := &protocol.Point{Values: make([]*protocol.FieldValue, fieldCount, fieldCount)}
for i, it := range iterators {
if rawColumnValues[i].value != nil || !it.Valid() {
if err := it.Error(); err != nil {
return err
}
continue
}
key := it.Key()
if len(key) < 16 {
continue
}
if !isPointInRange(fields[i].Id, startTimeBytes, endTimeBytes, key) {
continue
}
value := it.Value()
sequenceNumber := key[16:]
rawTime := key[8:16]
rawColumnValues[i] = rawColumnValue{time: rawTime, sequence: sequenceNumber, value: value}
}
var pointTimeRaw []byte
var pointSequenceRaw []byte
// choose the highest (or lowest in case of ascending queries) timestamp
// and sequence number. that will become the timestamp and sequence of
// the next point.
for _, value := range rawColumnValues {
if value.value == nil {
continue
}
pointTimeRaw, pointSequenceRaw = value.updatePointTimeAndSequence(pointTimeRaw,
pointSequenceRaw, query.Ascending)
}
for i, iterator := range iterators {
// if the value is nil or doesn't match the point's timestamp and sequence number
// then skip it
if rawColumnValues[i].value == nil ||
!bytes.Equal(rawColumnValues[i].time, pointTimeRaw) ||
!bytes.Equal(rawColumnValues[i].sequence, pointSequenceRaw) {
point.Values[i] = &protocol.FieldValue{IsNull: &TRUE}
continue
}
// if we emitted at lease one column, then we should keep
// trying to get more points
isValid = true
// advance the iterator to read a new value in the next iteration
if query.Ascending {
iterator.Next()
} else {
iterator.Prev()
}
fv := &protocol.FieldValue{}
valueBuffer.SetBuf(rawColumnValues[i].value)
err := valueBuffer.Unmarshal(fv)
if err != nil {
log.Error("Error while running query: %s", err)
return err
}
point.Values[i] = fv
rawColumnValues[i].value = nil
}
var sequence uint64
var t uint64
// set the point sequence number and timestamp
buffer.Reset()
buffer.Write(pointSequenceRaw)
binary.Read(buffer, binary.BigEndian, &sequence)
buffer.Reset()
buffer.Write(pointTimeRaw)
binary.Read(buffer, binary.BigEndian, &t)
time := self.convertUintTimestampToInt64(&t)
point.SetTimestampInMicroseconds(time)
point.SequenceNumber = &sequence
// stop the loop if we ran out of points
if !isValid {
break
}
shouldContinue := true
seriesOutgoing.Points = append(seriesOutgoing.Points, point)
if len(seriesOutgoing.Points) >= self.pointBatchSize {
for _, alias := range aliases {
series := &protocol.Series{
Name: proto.String(alias),
Fields: fieldNames,
Points: seriesOutgoing.Points,
}
if !processor.YieldSeries(series) {
log.Info("Stopping processing")
shouldContinue = false
}
}
seriesOutgoing = &protocol.Series{Name: protocol.String(seriesName), Fields: fieldNames, Points: make([]*protocol.Point, 0, self.pointBatchSize)}
}
if !shouldContinue {
break
}
}
//Yield remaining data
for _, alias := range aliases {
log.Debug("Final Flush %s", alias)
series := &protocol.Series{Name: protocol.String(alias), Fields: seriesOutgoing.Fields, Points: seriesOutgoing.Points}
if !processor.YieldSeries(series) {
log.Debug("Cancelled...")
}
}
log.Debug("Finished running query %s", query.GetQueryString())
return nil
}