influxdb/storage/series_cursor.go

142 lines
3.0 KiB
Go

package storage
import (
"bytes"
"errors"
"github.com/influxdata/influxdb"
"github.com/influxdata/influxdb/models"
"github.com/influxdata/influxdb/pkg/lifecycle"
"github.com/influxdata/influxdb/tsdb"
"github.com/influxdata/influxdb/tsdb/tsi1"
"github.com/influxdata/influxql"
)
var (
errUnexpectedOrg = errors.New("seriesCursor: unexpected org")
errUnexpectedTagComparisonOperator = errors.New("seriesCursor: unexpected tag comparison operator")
)
type SeriesCursor interface {
Close() error
Next() (*SeriesCursorRow, error)
}
type SeriesCursorRequest struct {
// Name contains the tsdb encoded org and bucket ID
Name [influxdb.IDLength]byte
}
// seriesCursor is an implementation of SeriesCursor over an tsi1.Index.
type seriesCursor struct {
index *tsi1.Index
indexref *lifecycle.Reference
sfile *tsdb.SeriesFile
sfileref *lifecycle.Reference
name [influxdb.IDLength]byte
keys [][]byte
ofs int
row SeriesCursorRow
cond influxql.Expr
init bool
}
type SeriesCursorRow struct {
Name []byte
Tags models.Tags
}
// newSeriesCursor returns a new instance of SeriesCursor.
func newSeriesCursor(req SeriesCursorRequest, index *tsi1.Index, sfile *tsdb.SeriesFile, cond influxql.Expr) (SeriesCursor, error) {
if cond != nil {
var err error
influxql.WalkFunc(cond, func(node influxql.Node) {
switch n := node.(type) {
case *influxql.BinaryExpr:
switch n.Op {
case influxql.EQ, influxql.NEQ, influxql.EQREGEX, influxql.NEQREGEX, influxql.OR, influxql.AND:
default:
err = errUnexpectedTagComparisonOperator
}
}
})
if err != nil {
return nil, err
}
}
indexref, err := index.Acquire()
if err != nil {
return nil, err
}
sfileref, err := sfile.Acquire()
if err != nil {
indexref.Release()
return nil, err
}
return &seriesCursor{
index: index,
indexref: indexref,
sfile: sfile,
sfileref: sfileref,
name: req.Name,
cond: cond,
}, nil
}
// Close closes the iterator. Safe to call multiple times.
func (cur *seriesCursor) Close() error {
cur.sfileref.Release()
cur.indexref.Release()
return nil
}
// Next emits the next point in the iterator.
func (cur *seriesCursor) Next() (*SeriesCursorRow, error) {
if !cur.init {
if err := cur.readSeriesKeys(); err != nil {
return nil, err
}
cur.init = true
}
if cur.ofs < len(cur.keys) {
cur.row.Name, cur.row.Tags = tsdb.ParseSeriesKeyInto(cur.keys[cur.ofs], cur.row.Tags)
if !bytes.HasPrefix(cur.row.Name, cur.name[:influxdb.OrgIDLength]) {
return nil, errUnexpectedOrg
}
cur.ofs++
return &cur.row, nil
}
return nil, nil
}
func (cur *seriesCursor) readSeriesKeys() error {
sitr, err := cur.index.MeasurementSeriesByExprIterator(cur.name[:], cur.cond)
if err != nil {
return err
} else if sitr == nil {
return nil
}
defer sitr.Close()
for {
elem, err := sitr.Next()
if err != nil {
return err
} else if elem.SeriesID.IsZero() {
break
}
key := cur.sfile.SeriesKey(elem.SeriesID)
if len(key) == 0 {
continue
}
cur.keys = append(cur.keys, key)
}
return nil
}