// 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 TestIteratorOptions_MergeSorted(t *testing.T) { opt := influxql.IteratorOptions{} sorted := opt.MergeSorted() if !sorted { t.Error("expected no expression to be sorted, got unsorted") } opt.Expr = &influxql.VarRef{} sorted = opt.MergeSorted() if !sorted { t.Error("expected expression with varref to be sorted, got unsorted") } opt.Expr = &influxql.Call{} sorted = opt.MergeSorted() if sorted { t.Error("expected expression without varref to be unsorted, got sorted") } }
// 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 { inputs := make([]influxql.Iterator, 0, len(t.SeriesKeys)) 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]) { conditionFields[fields] = f fields++ } } input, err := e.createVarRefSeriesIterator(ref, mm, seriesKey, t, t.Filters[i], conditionFields[:fields], opt) if err != nil { return err } else if input == nil { continue } inputs = append(inputs, input) } 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 }