Golang influxql.Sources函数代码示例

// CreateIterator returns an iterator for the data in the shard.
func (s *Shard) CreateIterator(opt influxql.IteratorOptions) (influxql.Iterator, error) {
	if s.closed() {
		return nil, ErrEngineClosed
	}

	if influxql.Sources(opt.Sources).HasSystemSource() {
		return s.createSystemIterator(opt)
	}
	opt.Sources = influxql.Sources(opt.Sources).Filter(s.database, s.retentionPolicy)
	return s.engine.CreateIterator(opt)
}

// CreateIterator returns an iterator for the data in the shard.
func (s *Shard) CreateIterator(opt influxql.IteratorOptions) (influxql.Iterator, error) {
	if err := s.ready(); err != nil {
		return nil, err
	}

	if influxql.Sources(opt.Sources).HasSystemSource() {
		return s.createSystemIterator(opt)
	}
	opt.Sources = influxql.Sources(opt.Sources).Filter(s.database, s.retentionPolicy)
	return s.engine.CreateIterator(opt)
}

// Ensure the query executor can execute a basic query.
func TestQueryExecutor_ExecuteQuery_Select(t *testing.T) {
	sh := MustOpenShard()
	defer sh.Close()
	sh.MustWritePointsString(`
cpu,region=serverA value=1 0
cpu,region=serverA value=2 10
cpu,region=serverB value=3 20
`)

	e := NewQueryExecutor()
	e.MetaClient.ShardIDsByTimeRangeFn = func(sources influxql.Sources, tmin, tmax time.Time) (a []uint64, err error) {
		if !reflect.DeepEqual(sources, influxql.Sources([]influxql.Source{&influxql.Measurement{Database: "db0", RetentionPolicy: "rp0", Name: "cpu"}})) {
			t.Fatalf("unexpected sources: %s", spew.Sdump(sources))
		} else if tmin.IsZero() {
			t.Fatalf("unexpected tmin: %s", tmin)
		} else if tmax.IsZero() {
			t.Fatalf("unexpected tmax: %s", tmax)
		}
		return []uint64{100}, nil
	}
	e.Store.ShardsFn = func(ids []uint64) []*tsdb.Shard {
		if !reflect.DeepEqual(ids, []uint64{100}) {
			t.Fatalf("unexpected shard ids: %+v", ids)
		}
		return []*tsdb.Shard{sh.Shard}
	}

	res := e.MustExecuteQueryString("db0", `SELECT value FROM cpu`)
	if s := MustMarshalJSON(res); s != `[{"series":[{"name":"cpu","columns":["time","value"],"values":[["1970-01-01T00:00:00Z",1],["1970-01-01T00:00:10Z",2],["1970-01-01T00:00:20Z",3]]}]}]` {
		t.Fatalf("unexpected results: %s", s)
	}
}

// SeriesKeys returns a list of series in in all shards in a. If a series
// exists in multiple shards in a, all instances will be combined into a single
// Series by calling Combine on it.
func (a Shards) SeriesKeys(opt influxql.IteratorOptions) (influxql.SeriesList, error) {
	if influxql.Sources(opt.Sources).HasSystemSource() {
		// Only support a single system source.
		if len(opt.Sources) > 1 {
			return nil, errors.New("cannot select from multiple system sources")
		}
		// Meta queries don't need to know the series name and always have a single string.
		return []influxql.Series{{Aux: []influxql.DataType{influxql.String}}}, nil
	}

	seriesMap := make(map[string]influxql.Series)
	for _, sh := range a {
		series, err := sh.SeriesKeys(opt)
		if err != nil {
			return nil, err
		}

		for _, s := range series {
			cur, ok := seriesMap[s.ID()]
			if ok {
				cur.Combine(&s)
			} else {
				seriesMap[s.ID()] = s
			}
		}
	}

	seriesList := make([]influxql.Series, 0, len(seriesMap))
	for _, s := range seriesMap {
		seriesList = append(seriesList, s)
	}
	sort.Sort(influxql.SeriesList(seriesList))
	return influxql.SeriesList(seriesList), nil
}

// FieldDimensions returns unique sets of fields and dimensions across a list of sources.
func (s *Shard) FieldDimensions(sources influxql.Sources) (fields map[string]influxql.DataType, dimensions map[string]struct{}, err error) {
	if influxql.Sources(sources).HasSystemSource() {
		// Only support a single system source.
		if len(sources) > 1 {
			return nil, nil, errors.New("cannot select from multiple system sources")
		}

		switch m := sources[0].(type) {
		case *influxql.Measurement:
			switch m.Name {
			case "_fieldKeys":
				return map[string]influxql.DataType{
					"fieldKey":  influxql.String,
					"fieldType": influxql.String,
				}, nil, nil
			case "_measurements":
				return map[string]influxql.DataType{"_name": influxql.String}, nil, nil
			case "_series":
				return map[string]influxql.DataType{"key": influxql.String}, nil, nil
			case "_tagKeys":
				return map[string]influxql.DataType{"tagKey": influxql.String}, nil, nil
			case "_tags":
				return map[string]influxql.DataType{
					"_tagKey": influxql.String,
					"value":   influxql.String,
				}, nil, nil
			}
		}
		return nil, nil, nil
	}

	fields = make(map[string]influxql.DataType)
	dimensions = make(map[string]struct{})

	for _, src := range sources {
		switch m := src.(type) {
		case *influxql.Measurement:
			// Retrieve measurement.
			mm := s.index.Measurement(m.Name)
			if mm == nil {
				continue
			}

			// Append fields and dimensions.
			mf := s.engine.MeasurementFields(m.Name)
			if mf != nil {
				for name, typ := range mf.FieldSet() {
					fields[name] = typ
				}
			}
			for _, key := range mm.TagKeys() {
				dimensions[key] = struct{}{}
			}
		}
	}

	return
}

// CreateIterator returns an iterator for the data in the shard.
func (s *Shard) CreateIterator(opt influxql.IteratorOptions) (influxql.Iterator, error) {
	if s.closed() {
		return nil, ErrEngineClosed
	}

	if influxql.Sources(opt.Sources).HasSystemSource() {
		return s.createSystemIterator(opt)
	}
	return s.engine.CreateIterator(opt)
}

func (e *Engine) SeriesKeys(opt influxql.IteratorOptions) (influxql.SeriesList, error) {
	seriesList := influxql.SeriesList{}
	mms := tsdb.Measurements(e.index.MeasurementsByName(influxql.Sources(opt.Sources).Names()))
	for _, mm := range mms {
		// Determine tagsets for this measurement based on dimensions and filters.
		tagSets, err := mm.TagSets(opt.Dimensions, opt.Condition)
		if err != nil {
			return nil, err
		}

		// Calculate tag sets and apply SLIMIT/SOFFSET.
		tagSets = influxql.LimitTagSets(tagSets, opt.SLimit, opt.SOffset)
		for _, t := range tagSets {
			series := influxql.Series{
				Name: mm.Name,
				Tags: influxql.NewTags(t.Tags),
				Aux:  make([]influxql.DataType, len(opt.Aux)),
			}

			// Determine the aux field types.
			for _, seriesKey := range t.SeriesKeys {
				tags := influxql.NewTags(e.index.TagsForSeries(seriesKey))
				for i, field := range opt.Aux {
					typ := func() influxql.DataType {
						mf := e.measurementFields[mm.Name]
						if mf == nil {
							return influxql.Unknown
						}

						f := mf.Field(field)
						if f == nil {
							return influxql.Unknown
						}
						return f.Type
					}()

					if typ == influxql.Unknown {
						if v := tags.Value(field); v != "" {
							// All tags are strings.
							typ = influxql.String
						}
					}

					if typ != influxql.Unknown {
						if series.Aux[i] == influxql.Unknown || typ < series.Aux[i] {
							series.Aux[i] = typ
						}
					}
				}
			}
			seriesList = append(seriesList, series)
		}
	}
	return seriesList, nil
}

// planShowMeasurements converts the statement to a SELECT and executes it.
func (q *QueryExecutor) planShowMeasurements(stmt *influxql.ShowMeasurementsStatement, database string, chunkSize int) (Executor, error) {
	// Check for time in WHERE clause (not supported).
	if influxql.HasTimeExpr(stmt.Condition) {
		return nil, errors.New("SHOW MEASUREMENTS doesn't support time in WHERE clause")
	}

	condition := stmt.Condition
	if source, ok := stmt.Source.(*influxql.Measurement); ok {
		var expr influxql.Expr
		if source.Regex != nil {
			expr = &influxql.BinaryExpr{
				Op:  influxql.EQREGEX,
				LHS: &influxql.VarRef{Val: "name"},
				RHS: &influxql.RegexLiteral{Val: source.Regex.Val},
			}
		} else if source.Name != "" {
			expr = &influxql.BinaryExpr{
				Op:  influxql.EQ,
				LHS: &influxql.VarRef{Val: "name"},
				RHS: &influxql.StringLiteral{Val: source.Name},
			}
		}

		// Set condition or "AND" together.
		if condition == nil {
			condition = expr
		} else {
			condition = &influxql.BinaryExpr{Op: influxql.AND, LHS: expr, RHS: condition}
		}
	}

	ss := &influxql.SelectStatement{
		Fields: influxql.Fields([]*influxql.Field{
			{Expr: &influxql.VarRef{Val: "name"}},
		}),
		Sources: influxql.Sources([]influxql.Source{
			&influxql.Measurement{Name: "_measurements"},
		}),
		Condition:  condition,
		Offset:     stmt.Offset,
		Limit:      stmt.Limit,
		SortFields: stmt.SortFields,
		OmitTime:   true,
		Dedupe:     true,
	}

	// Normalize the statement.
	if err := q.normalizeStatement(ss, database); err != nil {
		return nil, err
	}

	return q.PlanSelect(ss, chunkSize)
}

// createVarRefIterator creates an iterator for a variable reference.
func (e *Engine) createVarRefIterator(opt influxql.IteratorOptions) ([]influxql.Iterator, error) {
	ref, _ := opt.Expr.(*influxql.VarRef)

	var itrs []influxql.Iterator
	if err := func() error {
		mms := tsdb.Measurements(e.index.MeasurementsByName(influxql.Sources(opt.Sources).Names()))

		// Retrieve the maximum number of fields (without time).
		conditionFields := make([]string, len(influxql.ExprNames(opt.Condition)))

		for _, mm := range mms {
			// Determine tagsets for this measurement based on dimensions and filters.
			tagSets, err := mm.TagSets(opt.Dimensions, opt.Condition)
			if err != nil {
				return err
			}

			// Calculate tag sets and apply SLIMIT/SOFFSET.
			tagSets = influxql.LimitTagSets(tagSets, opt.SLimit, opt.SOffset)

			for _, t := range tagSets {
				for i, seriesKey := range t.SeriesKeys {
					fields := 0
					if t.Filters[i] != nil {
						// Retrieve non-time fields from this series filter and filter out tags.
						for _, f := range influxql.ExprNames(t.Filters[i]) {
							if mm.HasField(f) {
								conditionFields[fields] = f
								fields++
							}
						}
					}

					itr, err := e.createVarRefSeriesIterator(ref, mm, seriesKey, t, t.Filters[i], conditionFields[:fields], opt)
					if err != nil {
						return err
					} else if itr == nil {
						continue
					}
					itrs = append(itrs, itr)
				}
			}
		}
		return nil
	}(); err != nil {
		influxql.Iterators(itrs).Close()
		return nil, err
	}

	return itrs, nil
}

func TestSources_HasSystemSource(t *testing.T) {
	sources := influxql.Sources([]influxql.Source{
		&influxql.Measurement{
			Name: "_measurements",
		},
	})

	ok := sources.HasSystemSource()
	if !ok {
		t.Errorf("expected to find a system source, found none")
	}

	sources = influxql.Sources([]influxql.Source{
		&influxql.Measurement{
			Name: "cpu",
		},
	})

	ok = sources.HasSystemSource()
	if ok {
		t.Errorf("expected to find no system source, found one")
	}
}

func TestSources_Names(t *testing.T) {
	sources := influxql.Sources([]influxql.Source{
		&influxql.Measurement{
			Name: "cpu",
		},
		&influxql.Measurement{
			Name: "mem",
		},
	})

	names := sources.Names()
	if names[0] != "cpu" {
		t.Errorf("expected cpu, got %s", names[0])
	}
	if names[1] != "mem" {
		t.Errorf("expected mem, got %s", names[1])
	}
}

// SeriesKeys returns a list of series in the shard.
func (s *Shard) SeriesKeys(opt influxql.IteratorOptions) (influxql.SeriesList, error) {
	if influxql.Sources(opt.Sources).HasSystemSource() {
		// Only support a single system source.
		if len(opt.Sources) > 1 {
			return nil, errors.New("cannot select from multiple system sources")
		}

		// Meta queries don't need to know the series name and
		// always have a single series of strings.
		auxFields := make([]influxql.DataType, len(opt.Aux))
		for i := range auxFields {
			auxFields[i] = influxql.String
		}
		return []influxql.Series{{Aux: auxFields}}, nil
	}

	return s.engine.SeriesKeys(opt)
}

// createVarRefIterator creates an iterator for a variable reference.
func (e *Engine) createVarRefIterator(opt influxql.IteratorOptions) ([]influxql.Iterator, error) {
	ref, _ := opt.Expr.(*influxql.VarRef)

	var itrs []influxql.Iterator
	if err := func() error {
		mms := tsdb.Measurements(e.index.MeasurementsByName(influxql.Sources(opt.Sources).Names()))

		for _, mm := range mms {
			// Determine tagsets for this measurement based on dimensions and filters.
			tagSets, err := mm.TagSets(opt.Dimensions, opt.Condition)
			if err != nil {
				return err
			}

			// Calculate tag sets and apply SLIMIT/SOFFSET.
			tagSets = influxql.LimitTagSets(tagSets, opt.SLimit, opt.SOffset)

			for _, t := range tagSets {
				inputs, err := e.createTagSetIterators(ref, mm, t, opt)
				if err != nil {
					return err
				}

				if len(inputs) > 0 && (opt.Limit > 0 || opt.Offset > 0) {
					var itr influxql.Iterator
					if opt.MergeSorted() {
						itr = influxql.NewSortedMergeIterator(inputs, opt)
					} else {
						itr = influxql.NewMergeIterator(inputs, opt)
					}
					itrs = append(itrs, newLimitIterator(itr, opt))
				} else {
					itrs = append(itrs, inputs...)
				}
			}
		}
		return nil
	}(); err != nil {
		influxql.Iterators(itrs).Close()
		return nil, err
	}

	return itrs, nil
}

// 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
}

func (e *StatementExecutor) createIterators(stmt *influxql.SelectStatement, ctx *influxql.ExecutionContext) ([]influxql.Iterator, *influxql.SelectStatement, error) {
	// It is important to "stamp" this time so that everywhere we evaluate `now()` in the statement is EXACTLY the same `now`
	now := time.Now().UTC()
	opt := influxql.SelectOptions{
		InterruptCh: ctx.InterruptCh,
		NodeID:      ctx.ExecutionOptions.NodeID,
		MaxSeriesN:  e.MaxSelectSeriesN,
	}

	// Replace instances of "now()" with the current time, and check the resultant times.
	nowValuer := influxql.NowValuer{Now: now}
	stmt.Condition = influxql.Reduce(stmt.Condition, &nowValuer)
	// Replace instances of "now()" with the current time in the dimensions.
	for _, d := range stmt.Dimensions {
		d.Expr = influxql.Reduce(d.Expr, &nowValuer)
	}

	var err error
	opt.MinTime, opt.MaxTime, err = influxql.TimeRange(stmt.Condition)
	if err != nil {
		return nil, stmt, err
	}

	if opt.MaxTime.IsZero() {
		// In the case that we're executing a meta query where the user cannot
		// specify a time condition, then we expand the default max time
		// to the maximum possible value, to ensure that data where all points
		// are in the future are returned.
		if influxql.Sources(stmt.Sources).HasSystemSource() {
			opt.MaxTime = time.Unix(0, influxql.MaxTime).UTC()
		} else {
			if interval, err := stmt.GroupByInterval(); err != nil {
				return nil, stmt, err
			} else if interval > 0 {
				opt.MaxTime = now
			} else {
				opt.MaxTime = time.Unix(0, influxql.MaxTime).UTC()
			}
		}
	}
	if opt.MinTime.IsZero() {
		opt.MinTime = time.Unix(0, influxql.MinTime).UTC()
	}

	// Convert DISTINCT into a call.
	stmt.RewriteDistinct()

	// Remove "time" from fields list.
	stmt.RewriteTimeFields()

	// Rewrite any regex conditions that could make use of the index.
	stmt.RewriteRegexConditions()

	// Create an iterator creator based on the shards in the cluster.
	ic, err := e.iteratorCreator(stmt, &opt)
	if err != nil {
		return nil, stmt, err
	}

	// Expand regex sources to their actual source names.
	if stmt.Sources.HasRegex() {
		sources, err := ic.ExpandSources(stmt.Sources)
		if err != nil {
			return nil, stmt, err
		}
		stmt.Sources = sources
	}

	// Rewrite wildcards, if any exist.
	tmp, err := stmt.RewriteFields(ic)
	if err != nil {
		return nil, stmt, err
	}
	stmt = tmp

	if e.MaxSelectBucketsN > 0 && !stmt.IsRawQuery {
		interval, err := stmt.GroupByInterval()
		if err != nil {
			return nil, stmt, err
		}

		if interval > 0 {
			// Determine the start and end time matched to the interval (may not match the actual times).
			min := opt.MinTime.Truncate(interval)
			max := opt.MaxTime.Truncate(interval).Add(interval)

			// Determine the number of buckets by finding the time span and dividing by the interval.
			buckets := int64(max.Sub(min)) / int64(interval)
			if int(buckets) > e.MaxSelectBucketsN {
				return nil, stmt, fmt.Errorf("max-select-buckets limit exceeded: (%d/%d)", buckets, e.MaxSelectBucketsN)
			}
		}
	}

	// Create a set of iterators from a selection.
	itrs, err := influxql.Select(stmt, ic, &opt)
	if err != nil {
		return nil, stmt, err
	}

//.........这里部分代码省略.........