/
group_by.go
71 lines (60 loc) · 1.4 KB
/
group_by.go
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package executor
import (
"github.com/gotodb/gotodb/datatype"
"github.com/gotodb/gotodb/metadata"
"github.com/gotodb/gotodb/pb"
"github.com/gotodb/gotodb/row"
"github.com/gotodb/gotodb/stage"
"github.com/gotodb/gotodb/util"
"github.com/vmihailenco/msgpack"
"io"
)
func (e *Executor) SetInstructionGroupBy(instruction *pb.Instruction) (err error) {
var job stage.GroupByJob
if err = msgpack.Unmarshal(instruction.EncodedStageJobBytes, &job); err != nil {
return err
}
e.StageJob = &job
return nil
}
func (e *Executor) RunGroupBy() error {
job := e.StageJob.(*stage.GroupByJob)
md := &metadata.Metadata{}
reader := e.Readers[0]
writer := e.Writers[0]
if err := util.ReadObject(reader, md); err != nil {
return err
}
//write metadata
job.Metadata.ClearKeys()
job.Metadata.AppendKeyByType(datatype.STRING)
if err := util.WriteObject(writer, job.Metadata); err != nil {
return err
}
rbReader := row.NewRowsBuffer(md, reader, nil)
rbWriter := row.NewRowsBuffer(job.Metadata, nil, writer)
if err := job.GroupBy.Init(md); err != nil {
return err
}
for {
rg, err := rbReader.Read()
if err != nil {
if err == io.EOF {
err = nil
}
break
}
keys, err := job.GroupBy.Result(rg)
if err != nil {
return err
}
rg.AppendKeyColumns(keys)
if err := rbWriter.Write(rg); err != nil {
return err
}
}
if err := rbWriter.Flush(); err != nil {
return err
}
return nil
}