iterator.go
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package influxql
import (
"errors"
"fmt"
"io"
"sync"
"time"
"github.com/influxdata/influxdb/models"
"github.com/gogo/protobuf/proto"
internal "github.com/influxdata/influxdb/influxql/internal"
)
// ErrUnknownCall is returned when operating on an unknown function call.
var ErrUnknownCall = errors.New("unknown call")
const (
// MinTime is used as the minimum time value when computing an unbounded range.
// This time is one less than the MinNanoTime so that the first minimum
// time can be used as a sentinel value to signify that it is the default
// value rather than explicitly set by the user.
MinTime = models.MinNanoTime - 1
// MaxTime is used as the maximum time value when computing an unbounded range.
// This time is 2262-04-11 23:47:16.854775806 +0000 UTC
MaxTime = models.MaxNanoTime
// secToNs is the number of nanoseconds in a second.
secToNs = int64(time.Second)
)
// Iterator represents a generic interface for all Iterators.
// Most iterator operations are done on the typed sub-interfaces.
type Iterator interface {
Stats() IteratorStats
Close() error
}
// Iterators represents a list of iterators.
type Iterators []Iterator
// Stats returns the aggregation of all iterator stats.
func (a Iterators) Stats() IteratorStats {
var stats IteratorStats
for _, itr := range a {
stats.Add(itr.Stats())
}
return stats
}
// Close closes all iterators.
func (a Iterators) Close() error {
for _, itr := range a {
itr.Close()
}
return nil
}
// filterNonNil returns a slice of iterators that removes all nil iterators.
func (a Iterators) filterNonNil() []Iterator {
other := make([]Iterator, 0, len(a))
for _, itr := range a {
if itr == nil {
continue
}
other = append(other, itr)
}
return other
}
// castType determines what type to cast the set of iterators to.
// An iterator type is chosen using this hierarchy:
// float > integer > string > boolean
func (a Iterators) castType() DataType {
if len(a) == 0 {
return Unknown
}
typ := DataType(Boolean)
for _, input := range a {
switch input.(type) {
case FloatIterator:
// Once a float iterator is found, short circuit the end.
return Float
case IntegerIterator:
if typ > Integer {
typ = Integer
}
case StringIterator:
if typ > String {
typ = String
}
case BooleanIterator:
// Boolean is the lowest type.
}
}
return typ
}
// cast casts an array of iterators to a single type.
// Iterators that are not compatible or cannot be cast to the
// chosen iterator type are closed and dropped.
func (a Iterators) cast() interface{} {
typ := a.castType()
switch typ {
case Float:
return newFloatIterators(a)
case Integer:
return newIntegerIterators(a)
case String:
return newStringIterators(a)
case Boolean:
return newBooleanIterators(a)
}
return a
}
// Merge combines all iterators into a single iterator.
// A sorted merge iterator or a merge iterator can be used based on opt.
func (a Iterators) Merge(opt IteratorOptions) (Iterator, error) {
// Check if this is a call expression.
call, ok := opt.Expr.(*Call)
// Merge into a single iterator.
if !ok && opt.MergeSorted() {
itr := NewSortedMergeIterator(a, opt)
if itr != nil && opt.InterruptCh != nil {
itr = NewInterruptIterator(itr, opt.InterruptCh)
}
return itr, nil
}
// We do not need an ordered output so use a merge iterator.
itr := NewMergeIterator(a, opt)
if itr == nil {
return nil, nil
}
if opt.InterruptCh != nil {
itr = NewInterruptIterator(itr, opt.InterruptCh)
}
if !ok {
// This is not a call expression so do not use a call iterator.
return itr, nil
}
// When merging the count() function, use sum() to sum the counted points.
if call.Name == "count" {
opt.Expr = &Call{
Name: "sum",
Args: call.Args,
}
}
return NewCallIterator(itr, opt)
}
// NewMergeIterator returns an iterator to merge itrs into one.
// Inputs must either be merge iterators or only contain a single name/tag in
// sorted order. The iterator will output all points by window, name/tag, then
// time. This iterator is useful when you need all of the points for an
// interval.
func NewMergeIterator(inputs []Iterator, opt IteratorOptions) Iterator {
inputs = Iterators(inputs).filterNonNil()
if n := len(inputs); n == 0 {
return nil
} else if n == 1 {
return inputs[0]
}
// Aggregate functions can use a more relaxed sorting so that points
// within a window are grouped. This is much more efficient.
switch inputs := Iterators(inputs).cast().(type) {
case []FloatIterator:
return newFloatMergeIterator(inputs, opt)
case []IntegerIterator:
return newIntegerMergeIterator(inputs, opt)
case []StringIterator:
return newStringMergeIterator(inputs, opt)
case []BooleanIterator:
return newBooleanMergeIterator(inputs, opt)
default:
panic(fmt.Sprintf("unsupported merge iterator type: %T", inputs))
}
}
// NewParallelMergeIterator returns an iterator that breaks input iterators
// into groups and processes them in parallel.
func NewParallelMergeIterator(inputs []Iterator, opt IteratorOptions, parallelism int) Iterator {
inputs = Iterators(inputs).filterNonNil()
if len(inputs) == 0 {
return nil
} else if len(inputs) == 1 {
return inputs[0]
}
// Limit parallelism to the number of inputs.
if len(inputs) < parallelism {
parallelism = len(inputs)
}
// Determine the number of inputs per output iterator.
n := len(inputs) / parallelism
// Group iterators together.
outputs := make([]Iterator, parallelism)
for i := range outputs {
var slice []Iterator
if i < len(outputs)-1 {
slice = inputs[i*n : (i+1)*n]
} else {
slice = inputs[i*n:]
}
outputs[i] = newParallelIterator(NewMergeIterator(slice, opt))
}
// Merge all groups together.
return NewMergeIterator(outputs, opt)
}
// NewSortedMergeIterator returns an iterator to merge itrs into one.
// Inputs must either be sorted merge iterators or only contain a single
// name/tag in sorted order. The iterator will output all points by name/tag,
// then time. This iterator is useful when you need all points for a name/tag
// to be in order.
func NewSortedMergeIterator(inputs []Iterator, opt IteratorOptions) Iterator {
inputs = Iterators(inputs).filterNonNil()
if len(inputs) == 0 {
return nil
} else if len(inputs) == 1 {
return inputs[0]
}
switch inputs := Iterators(inputs).cast().(type) {
case []FloatIterator:
return newFloatSortedMergeIterator(inputs, opt)
case []IntegerIterator:
return newIntegerSortedMergeIterator(inputs, opt)
case []StringIterator:
return newStringSortedMergeIterator(inputs, opt)
case []BooleanIterator:
return newBooleanSortedMergeIterator(inputs, opt)
default:
panic(fmt.Sprintf("unsupported sorted merge iterator type: %T", inputs))
}
}
// newParallelIterator returns an iterator that runs in a separate goroutine.
func newParallelIterator(input Iterator) Iterator {
if input == nil {
return nil
}
switch itr := input.(type) {
case FloatIterator:
return newFloatParallelIterator(itr)
case IntegerIterator:
return newIntegerParallelIterator(itr)
case StringIterator:
return newStringParallelIterator(itr)
case BooleanIterator:
return newBooleanParallelIterator(itr)
default:
panic(fmt.Sprintf("unsupported parallel iterator type: %T", itr))
}
}
// NewLimitIterator returns an iterator that limits the number of points per grouping.
func NewLimitIterator(input Iterator, opt IteratorOptions) Iterator {
switch input := input.(type) {
case FloatIterator:
return newFloatLimitIterator(input, opt)
case IntegerIterator:
return newIntegerLimitIterator(input, opt)
case StringIterator:
return newStringLimitIterator(input, opt)
case BooleanIterator:
return newBooleanLimitIterator(input, opt)
default:
panic(fmt.Sprintf("unsupported limit iterator type: %T", input))
}
}
// NewFilterIterator returns an iterator that filters the points based on the
// condition. This iterator is not nearly as efficient as filtering points
// within the query engine and is only used when filtering subqueries.
func NewFilterIterator(input Iterator, cond Expr, opt IteratorOptions) Iterator {
if input == nil {
return nil
}
switch input := input.(type) {
case FloatIterator:
return newFloatFilterIterator(input, cond, opt)
case IntegerIterator:
return newIntegerFilterIterator(input, cond, opt)
case StringIterator:
return newStringFilterIterator(input, cond, opt)
case BooleanIterator:
return newBooleanFilterIterator(input, cond, opt)
default:
panic(fmt.Sprintf("unsupported filter iterator type: %T", input))
}
}
// NewDedupeIterator returns an iterator that only outputs unique points.
// This iterator maintains a serialized copy of each row so it is inefficient
// to use on large datasets. It is intended for small datasets such as meta queries.
func NewDedupeIterator(input Iterator) Iterator {
if input == nil {
return nil
}
switch input := input.(type) {
case FloatIterator:
return newFloatDedupeIterator(input)
case IntegerIterator:
return newIntegerDedupeIterator(input)
case StringIterator:
return newStringDedupeIterator(input)
case BooleanIterator:
return newBooleanDedupeIterator(input)
default:
panic(fmt.Sprintf("unsupported dedupe iterator type: %T", input))
}
}
// NewFillIterator returns an iterator that fills in missing points in an aggregate.
func NewFillIterator(input Iterator, expr Expr, opt IteratorOptions) Iterator {
switch input := input.(type) {
case FloatIterator:
return newFloatFillIterator(input, expr, opt)
case IntegerIterator:
return newIntegerFillIterator(input, expr, opt)
case StringIterator:
return newStringFillIterator(input, expr, opt)
case BooleanIterator:
return newBooleanFillIterator(input, expr, opt)
default:
panic(fmt.Sprintf("unsupported fill iterator type: %T", input))
}
}
// NewIntervalIterator returns an iterator that sets the time on each point to the interval.
func NewIntervalIterator(input Iterator, opt IteratorOptions) Iterator {
switch input := input.(type) {
case FloatIterator:
return newFloatIntervalIterator(input, opt)
case IntegerIterator:
return newIntegerIntervalIterator(input, opt)
case StringIterator:
return newStringIntervalIterator(input, opt)
case BooleanIterator:
return newBooleanIntervalIterator(input, opt)
default:
panic(fmt.Sprintf("unsupported fill iterator type: %T", input))
}
}
// NewInterruptIterator returns an iterator that will stop producing output
// when the passed-in channel is closed.
func NewInterruptIterator(input Iterator, closing <-chan struct{}) Iterator {
switch input := input.(type) {
case FloatIterator:
return newFloatInterruptIterator(input, closing)
case IntegerIterator:
return newIntegerInterruptIterator(input, closing)
case StringIterator:
return newStringInterruptIterator(input, closing)
case BooleanIterator:
return newBooleanInterruptIterator(input, closing)
default:
panic(fmt.Sprintf("unsupported interrupt iterator type: %T", input))
}
}
// NewCloseInterruptIterator returns an iterator that will invoke the Close() method on an
// iterator when the passed-in channel has been closed.
func NewCloseInterruptIterator(input Iterator, closing <-chan struct{}) Iterator {
switch input := input.(type) {
case FloatIterator:
return newFloatCloseInterruptIterator(input, closing)
case IntegerIterator:
return newIntegerCloseInterruptIterator(input, closing)
case StringIterator:
return newStringCloseInterruptIterator(input, closing)
case BooleanIterator:
return newBooleanCloseInterruptIterator(input, closing)
default:
panic(fmt.Sprintf("unsupported close iterator iterator type: %T", input))
}
}
// AuxIterator represents an iterator that can split off separate auxiliary iterators.
type AuxIterator interface {
Iterator
// Auxilary iterator
Iterator(name string, typ DataType) Iterator
// Start starts writing to the created iterators.
Start()
// Backgrounds the iterator so that, when start is called, it will
// continuously read from the iterator.
Background()
}
// NewAuxIterator returns a new instance of AuxIterator.
func NewAuxIterator(input Iterator, opt IteratorOptions) AuxIterator {
switch input := input.(type) {
case FloatIterator:
return newFloatAuxIterator(input, opt)
case IntegerIterator:
return newIntegerAuxIterator(input, opt)
case StringIterator:
return newStringAuxIterator(input, opt)
case BooleanIterator:
return newBooleanAuxIterator(input, opt)
default:
panic(fmt.Sprintf("unsupported aux iterator type: %T", input))
}
}
// auxIteratorField represents an auxilary field within an AuxIterator.
type auxIteratorField struct {
name string // field name
typ DataType // detected data type
itrs []Iterator // auxillary iterators
mu sync.Mutex
opt IteratorOptions
}
func (f *auxIteratorField) append(itr Iterator) {
f.mu.Lock()
defer f.mu.Unlock()
f.itrs = append(f.itrs, itr)
}
func (f *auxIteratorField) close() {
f.mu.Lock()
defer f.mu.Unlock()
for _, itr := range f.itrs {
itr.Close()
}
}
type auxIteratorFields struct {
fields []*auxIteratorField
dimensions []string
}
// newAuxIteratorFields returns a new instance of auxIteratorFields from a list of field names.
func newAuxIteratorFields(opt IteratorOptions) *auxIteratorFields {
fields := make([]*auxIteratorField, len(opt.Aux))
for i, ref := range opt.Aux {
fields[i] = &auxIteratorField{name: ref.Val, typ: ref.Type, opt: opt}
}
return &auxIteratorFields{
fields: fields,
dimensions: opt.GetDimensions(),
}
}
func (a *auxIteratorFields) close() {
for _, f := range a.fields {
f.close()
}
}
// iterator creates a new iterator for a named auxilary field.
func (a *auxIteratorFields) iterator(name string, typ DataType) Iterator {
for _, f := range a.fields {
// Skip field if it's name doesn't match.
// Exit if no points were received by the iterator.
if f.name != name || (typ != Unknown && f.typ != typ) {
continue
}
// Create channel iterator by data type.
switch f.typ {
case Float:
itr := &floatChanIterator{cond: sync.NewCond(&sync.Mutex{})}
f.append(itr)
return itr
case Integer:
itr := &integerChanIterator{cond: sync.NewCond(&sync.Mutex{})}
f.append(itr)
return itr
case String, Tag:
itr := &stringChanIterator{cond: sync.NewCond(&sync.Mutex{})}
f.append(itr)
return itr
case Boolean:
itr := &booleanChanIterator{cond: sync.NewCond(&sync.Mutex{})}
f.append(itr)
return itr
default:
break
}
}
return &nilFloatIterator{}
}
// send sends a point to all field iterators.
func (a *auxIteratorFields) send(p Point) (ok bool) {
values := p.aux()
for i, f := range a.fields {
var v interface{}
if i < len(values) {
v = values[i]
}
tags := p.tags()
tags = tags.Subset(a.dimensions)
// Send new point for each aux iterator.
// Primitive pointers represent nil values.
for _, itr := range f.itrs {
switch itr := itr.(type) {
case *floatChanIterator:
ok = itr.setBuf(p.name(), tags, p.time(), v) || ok
case *integerChanIterator:
ok = itr.setBuf(p.name(), tags, p.time(), v) || ok
case *stringChanIterator:
ok = itr.setBuf(p.name(), tags, p.time(), v) || ok
case *booleanChanIterator:
ok = itr.setBuf(p.name(), tags, p.time(), v) || ok
default:
panic(fmt.Sprintf("invalid aux itr type: %T", itr))
}
}
}
return ok
}
func (a *auxIteratorFields) sendError(err error) {
for _, f := range a.fields {
for _, itr := range f.itrs {
switch itr := itr.(type) {
case *floatChanIterator:
itr.setErr(err)
case *integerChanIterator:
itr.setErr(err)
case *stringChanIterator:
itr.setErr(err)
case *booleanChanIterator:
itr.setErr(err)
default:
panic(fmt.Sprintf("invalid aux itr type: %T", itr))
}
}
}
}
// DrainIterator reads and discards all points from itr.
func DrainIterator(itr Iterator) {
defer itr.Close()
switch itr := itr.(type) {
case FloatIterator:
for p, _ := itr.Next(); p != nil; p, _ = itr.Next() {
}
case IntegerIterator:
for p, _ := itr.Next(); p != nil; p, _ = itr.Next() {
}
case StringIterator:
for p, _ := itr.Next(); p != nil; p, _ = itr.Next() {
}
case BooleanIterator:
for p, _ := itr.Next(); p != nil; p, _ = itr.Next() {
}
default:
panic(fmt.Sprintf("unsupported iterator type for draining: %T", itr))
}
}
// DrainIterators reads and discards all points from itrs.
func DrainIterators(itrs []Iterator) {
defer Iterators(itrs).Close()
for {
var hasData bool
for _, itr := range itrs {
switch itr := itr.(type) {
case FloatIterator:
if p, _ := itr.Next(); p != nil {
hasData = true
}
case IntegerIterator:
if p, _ := itr.Next(); p != nil {
hasData = true
}
case StringIterator:
if p, _ := itr.Next(); p != nil {
hasData = true
}
case BooleanIterator:
if p, _ := itr.Next(); p != nil {
hasData = true
}
default:
panic(fmt.Sprintf("unsupported iterator type for draining: %T", itr))
}
}
// Exit once all iterators return a nil point.
if !hasData {
break
}
}
}
// NewReaderIterator returns an iterator that streams from a reader.
func NewReaderIterator(r io.Reader, typ DataType, stats IteratorStats) Iterator {
switch typ {
case Float:
return newFloatReaderIterator(r, stats)
case Integer:
return newIntegerReaderIterator(r, stats)
case String:
return newStringReaderIterator(r, stats)
case Boolean:
return newBooleanReaderIterator(r, stats)
default:
return &nilFloatIterator{}
}
}
// IteratorCreator is an interface to create Iterators.
type IteratorCreator interface {
// Creates a simple iterator for use in an InfluxQL query.
CreateIterator(source *Measurement, opt IteratorOptions) (Iterator, error)
}
// FieldMapper returns the data type for the field inside of the measurement.
type FieldMapper interface {
FieldDimensions(m *Measurement) (fields map[string]DataType, dimensions map[string]struct{}, err error)
TypeMapper
}
// IteratorOptions is an object passed to CreateIterator to specify creation options.
type IteratorOptions struct {
// Expression to iterate for.
// This can be VarRef or a Call.
Expr Expr
// Auxilary tags or values to also retrieve for the point.
Aux []VarRef
// Data sources from which to receive data. This is only used for encoding
// measurements over RPC and is no longer used in the open source version.
Sources []Source
// Group by interval and tags.
Interval Interval
Dimensions []string // The final dimensions of the query (stays the same even in subqueries).
GroupBy map[string]struct{} // Dimensions to group points by in intermediate iterators.
Location *time.Location
// Fill options.
Fill FillOption
FillValue interface{}
// Condition to filter by.
Condition Expr
// Time range for the iterator.
StartTime int64
EndTime int64
// Sorted in time ascending order if true.
Ascending bool
// Limits the number of points per series.
Limit, Offset int
// Limits the number of series.
SLimit, SOffset int
// Removes duplicate rows from raw queries.
Dedupe bool
// Determines if this is a query for raw data or an aggregate/selector.
Ordered bool
// Limits on the creation of iterators.
MaxSeriesN int
// If this channel is set and is closed, the iterator should try to exit
// and close as soon as possible.
InterruptCh <-chan struct{}
}
// newIteratorOptionsStmt creates the iterator options from stmt.
func newIteratorOptionsStmt(stmt *SelectStatement, sopt *SelectOptions) (opt IteratorOptions, err error) {
// Determine time range from the condition.
startTime, endTime, err := TimeRange(stmt.Condition)
if err != nil {
return IteratorOptions{}, err
}
if !startTime.IsZero() {
opt.StartTime = startTime.UnixNano()
} else {
if sopt != nil {
opt.StartTime = sopt.MinTime.UnixNano()
} else {
opt.StartTime = MinTime
}
}
if !endTime.IsZero() {
opt.EndTime = endTime.UnixNano()
} else {
if sopt != nil {
opt.EndTime = sopt.MaxTime.UnixNano()
} else {
opt.EndTime = MaxTime
}
}
opt.Location = stmt.Location
// Determine group by interval.
interval, err := stmt.GroupByInterval()
if err != nil {
return opt, err
}
// Set duration to zero if a negative interval has been used.
if interval < 0 {
interval = 0
} else if interval > 0 {
opt.Interval.Offset, err = stmt.GroupByOffset()
if err != nil {
return opt, err
}
}
opt.Interval.Duration = interval
// Always request an ordered output for the top level iterators.
// The emitter will always emit points as ordered.
opt.Ordered = true
// Determine dimensions.
opt.GroupBy = make(map[string]struct{}, len(opt.Dimensions))
for _, d := range stmt.Dimensions {
if d, ok := d.Expr.(*VarRef); ok {
opt.Dimensions = append(opt.Dimensions, d.Val)
opt.GroupBy[d.Val] = struct{}{}
}
}
opt.Condition = stmt.Condition
opt.Ascending = stmt.TimeAscending()
opt.Dedupe = stmt.Dedupe
opt.Fill, opt.FillValue = stmt.Fill, stmt.FillValue
if opt.Fill == NullFill && stmt.Target != nil {
// Set the fill option to none if a target has been given.
// Null values will get ignored when being written to the target
// so fill(null) wouldn't write any null values to begin with.
opt.Fill = NoFill
}
opt.Limit, opt.Offset = stmt.Limit, stmt.Offset
opt.SLimit, opt.SOffset = stmt.SLimit, stmt.SOffset
if sopt != nil {
opt.MaxSeriesN = sopt.MaxSeriesN
opt.InterruptCh = sopt.InterruptCh
}
return opt, nil
}
func newIteratorOptionsSubstatement(stmt *SelectStatement, opt IteratorOptions) (IteratorOptions, error) {
subOpt, err := newIteratorOptionsStmt(stmt, nil)
if err != nil {
return IteratorOptions{}, err
}
if subOpt.StartTime < opt.StartTime {
subOpt.StartTime = opt.StartTime
}
if subOpt.EndTime > opt.EndTime {
subOpt.EndTime = opt.EndTime
}
// Propagate the dimensions to the inner subquery.
subOpt.Dimensions = opt.Dimensions
for d := range opt.GroupBy {
subOpt.GroupBy[d] = struct{}{}
}
subOpt.InterruptCh = opt.InterruptCh
// Propagate the SLIMIT and SOFFSET from the outer query.
subOpt.SLimit += opt.SLimit
subOpt.SOffset += opt.SOffset
// If the inner query uses a null fill option, switch it to none so we
// don't hit an unnecessary penalty from the fill iterator. Null values
// will end up getting stripped by an outer query anyway so there's no
// point in having them here. We still need all other types of fill
// iterators because they can affect the result of the outer query.
if subOpt.Fill == NullFill {
subOpt.Fill = NoFill
}
// Inherit the ordering method from the outer query.
subOpt.Ordered = opt.Ordered
// If there is no interval for this subquery, but the outer query has an
// interval, inherit the parent interval.
interval, err := stmt.GroupByInterval()
if err != nil {
return IteratorOptions{}, err
} else if interval == 0 {
subOpt.Interval = opt.Interval
}
return subOpt, nil
}
// MergeSorted returns true if the options require a sorted merge.
func (opt IteratorOptions) MergeSorted() bool {
return opt.Ordered
}
// SeekTime returns the time the iterator should start from.
// For ascending iterators this is the start time, for descending iterators it's the end time.
func (opt IteratorOptions) SeekTime() int64 {
if opt.Ascending {
return opt.StartTime
}
return opt.EndTime
}
// Window returns the time window [start,end) that t falls within.
func (opt IteratorOptions) Window(t int64) (start, end int64) {
if opt.Interval.IsZero() {
return opt.StartTime, opt.EndTime + 1
}
// Subtract the offset to the time so we calculate the correct base interval.
t -= int64(opt.Interval.Offset)
// Retrieve the zone offset for the start time.
var startOffset int64
if opt.Location != nil {
_, startOffset = opt.Zone(t)
t += startOffset
}
// Truncate time by duration.
dt := t % int64(opt.Interval.Duration)
if dt < 0 {
// Negative modulo rounds up instead of down, so offset
// with the duration.
dt += int64(opt.Interval.Duration)
}
// Find the start time.
if MinTime+dt >= t {
start = MinTime
} else {
start = t - dt
}
// Look for the start offset again because the first time may have been
// after the offset switch. Now that we are at midnight in UTC, we can
// lookup the zone offset again to get the real starting offset.
if opt.Location != nil {
_, adjustedOffset := opt.Zone(start)
// Do not adjust the offset if the offset change is greater than or
// equal to the duration.
if o := startOffset - adjustedOffset; o != 0 && abs(o) < int64(opt.Interval.Duration) {
startOffset = adjustedOffset
}
}
start += int64(opt.Interval.Offset) - startOffset
// Find the end time.
if dt := int64(opt.Interval.Duration) - dt; MaxTime-dt <= t {
end = MaxTime
} else {
end = t + dt
}
end += int64(opt.Interval.Offset) - startOffset
// Retrieve the zone offset for the end time.
if opt.Location != nil {
_, endOffset := opt.Zone(end)
// Adjust the end time if the offset is different from the start offset.
if startOffset != endOffset {
offset := startOffset - endOffset
// Only apply the offset if it is smaller than the duration.
// This prevents going back in time and creating time windows
// that don't make any sense.
if abs(offset) < int64(opt.Interval.Duration) {
end += offset
}
}
}
return
}
// DerivativeInterval returns the time interval for the derivative function.
func (opt IteratorOptions) DerivativeInterval() Interval {
// Use the interval on the derivative() call, if specified.
if expr, ok := opt.Expr.(*Call); ok && len(expr.Args) == 2 {
return Interval{Duration: expr.Args[1].(*DurationLiteral).Val}
}
// Otherwise use the group by interval, if specified.
if opt.Interval.Duration > 0 {
return Interval{Duration: opt.Interval.Duration}
}
return Interval{Duration: time.Second}
}
// ElapsedInterval returns the time interval for the elapsed function.
func (opt IteratorOptions) ElapsedInterval() Interval {
// Use the interval on the elapsed() call, if specified.
if expr, ok := opt.Expr.(*Call); ok && len(expr.Args) == 2 {
return Interval{Duration: expr.Args[1].(*DurationLiteral).Val}
}
return Interval{Duration: time.Nanosecond}
}
// IntegralInterval returns the time interval for the integral function.
func (opt IteratorOptions) IntegralInterval() Interval {
// Use the interval on the integral() call, if specified.
if expr, ok := opt.Expr.(*Call); ok && len(expr.Args) == 2 {
return Interval{Duration: expr.Args[1].(*DurationLiteral).Val}
}
return Interval{Duration: time.Second}
}
// GetDimensions retrieves the dimensions for this query.
func (opt IteratorOptions) GetDimensions() []string {
if len(opt.GroupBy) > 0 {
dimensions := make([]string, 0, len(opt.GroupBy))
for dim := range opt.GroupBy {
dimensions = append(dimensions, dim)
}
return dimensions
}
return opt.Dimensions
}
// Zone returns the zone information for the given time. The offset is in nanoseconds.
func (opt *IteratorOptions) Zone(ns int64) (string, int64) {
if opt.Location == nil {
return "", 0
}
t := time.Unix(0, ns).In(opt.Location)
name, offset := t.Zone()
return name, secToNs * int64(offset)
}
// MarshalBinary encodes opt into a binary format.
func (opt *IteratorOptions) MarshalBinary() ([]byte, error) {
return proto.Marshal(encodeIteratorOptions(opt))
}
// UnmarshalBinary decodes from a binary format in to opt.
func (opt *IteratorOptions) UnmarshalBinary(buf []byte) error {
var pb internal.IteratorOptions
if err := proto.Unmarshal(buf, &pb); err != nil {
return err
}
other, err := decodeIteratorOptions(&pb)
if err != nil {
return err
}
*opt = *other
return nil
}
func encodeIteratorOptions(opt *IteratorOptions) *internal.IteratorOptions {
pb := &internal.IteratorOptions{
Interval: encodeInterval(opt.Interval),
Dimensions: opt.Dimensions,
Fill: proto.Int32(int32(opt.Fill)),
StartTime: proto.Int64(opt.StartTime),
EndTime: proto.Int64(opt.EndTime),
Ascending: proto.Bool(opt.Ascending),
Limit: proto.Int64(int64(opt.Limit)),
Offset: proto.Int64(int64(opt.Offset)),
SLimit: proto.Int64(int64(opt.SLimit)),
SOffset: proto.Int64(int64(opt.SOffset)),
Dedupe: proto.Bool(opt.Dedupe),
MaxSeriesN: proto.Int64(int64(opt.MaxSeriesN)),
Ordered: proto.Bool(opt.Ordered),
}
// Set expression, if set.
if opt.Expr != nil {
pb.Expr = proto.String(opt.Expr.String())
}
// Set the location, if set.
if opt.Location != nil {
pb.Location = proto.String(opt.Location.String())
}
// Convert and encode aux fields as variable references.
pb.Fields = make([]*internal.VarRef, len(opt.Aux))
pb.Aux = make([]string, len(opt.Aux))
for i, ref := range opt.Aux {
pb.Fields[i] = encodeVarRef(ref)
pb.Aux[i] = ref.Val
}
// Encode group by dimensions from a map.
if pb.GroupBy != nil {
dimensions := make([]string, 0, len(opt.GroupBy))
for dim := range opt.GroupBy {
dimensions = append(dimensions, dim)
}
pb.GroupBy = dimensions
}
// Convert and encode sources to measurements.
if opt.Sources != nil {
sources := make([]*internal.Measurement, len(opt.Sources))
for i, source := range opt.Sources {
mm := source.(*Measurement)
sources[i] = encodeMeasurement(mm)
}
pb.Sources = sources
}
// Fill value can only be a number. Set it if available.
if v, ok := opt.FillValue.(float64); ok {
pb.FillValue = proto.Float64(v)
}
// Set condition, if set.
if opt.Condition != nil {
pb.Condition = proto.String(opt.Condition.String())
}
return pb
}
func decodeIteratorOptions(pb *internal.IteratorOptions) (*IteratorOptions, error) {
opt := &IteratorOptions{
Interval: decodeInterval(pb.GetInterval()),
Dimensions: pb.GetDimensions(),
Fill: FillOption(pb.GetFill()),
FillValue: pb.GetFillValue(),
StartTime: pb.GetStartTime(),
EndTime: pb.GetEndTime(),
Ascending: pb.GetAscending(),
Limit: int(pb.GetLimit()),
Offset: int(pb.GetOffset()),
SLimit: int(pb.GetSLimit()),
SOffset: int(pb.GetSOffset()),
Dedupe: pb.GetDedupe(),
MaxSeriesN: int(pb.GetMaxSeriesN()),
Ordered: pb.GetOrdered(),
}
// Set expression, if set.
if pb.Expr != nil {
expr, err := ParseExpr(pb.GetExpr())
if err != nil {
return nil, err
}
opt.Expr = expr
}
if pb.Location != nil {
loc, err := time.LoadLocation(pb.GetLocation())
if err != nil {
return nil, err
}
opt.Location = loc
}
// Convert and decode variable references.
if fields := pb.GetFields(); fields != nil {
opt.Aux = make([]VarRef, len(fields))
for i, ref := range fields {
opt.Aux[i] = decodeVarRef(ref)
}
} else {
opt.Aux = make([]VarRef, len(pb.GetAux()))
for i, name := range pb.GetAux() {
opt.Aux[i] = VarRef{Val: name}
}
}
// Convert and decode sources to measurements.
if pb.Sources != nil {
sources := make([]Source, len(pb.GetSources()))
for i, source := range pb.GetSources() {
mm, err := decodeMeasurement(source)
if err != nil {
return nil, err
}
sources[i] = mm
}
opt.Sources = sources
}
// Convert group by dimensions to a map.
if pb.GroupBy != nil {
dimensions := make(map[string]struct{}, len(pb.GroupBy))
for _, dim := range pb.GetGroupBy() {
dimensions[dim] = struct{}{}
}
opt.GroupBy = dimensions
}
// Set condition, if set.
if pb.Condition != nil {
expr, err := ParseExpr(pb.GetCondition())
if err != nil {
return nil, err
}
opt.Condition = expr
}
return opt, nil
}
// selectInfo represents an object that stores info about select fields.
type selectInfo struct {
calls map[*Call]struct{}
refs map[*VarRef]struct{}
}
// newSelectInfo creates a object with call and var ref info from stmt.
func newSelectInfo(stmt *SelectStatement) *selectInfo {
info := &selectInfo{
calls: make(map[*Call]struct{}),
refs: make(map[*VarRef]struct{}),
}
Walk(info, stmt.Fields)
return info
}
func (v *selectInfo) Visit(n Node) Visitor {
switch n := n.(type) {
case *Call:
v.calls[n] = struct{}{}
return nil
case *VarRef:
v.refs[n] = struct{}{}
return nil
}
return v
}
// FindSelector returns a selector from the selectInfo. This will only
// return a selector if the Call is a selector and it's the only function
// in the selectInfo.
func (v *selectInfo) FindSelector() *Call {
if len(v.calls) != 1 {
return nil
}
for s := range v.calls {
if IsSelector(s) {
return s
}
}
return nil
}
// Interval represents a repeating interval for a query.
type Interval struct {
Duration time.Duration
Offset time.Duration
}
// IsZero returns true if the interval has no duration.
func (i Interval) IsZero() bool { return i.Duration == 0 }
func encodeInterval(i Interval) *internal.Interval {
return &internal.Interval{
Duration: proto.Int64(i.Duration.Nanoseconds()),
Offset: proto.Int64(i.Offset.Nanoseconds()),
}
}
func decodeInterval(pb *internal.Interval) Interval {
return Interval{
Duration: time.Duration(pb.GetDuration()),
Offset: time.Duration(pb.GetOffset()),
}
}
func encodeVarRef(ref VarRef) *internal.VarRef {
return &internal.VarRef{
Val: proto.String(ref.Val),
Type: proto.Int32(int32(ref.Type)),
}
}
func decodeVarRef(pb *internal.VarRef) VarRef {
return VarRef{
Val: pb.GetVal(),
Type: DataType(pb.GetType()),
}
}
type nilFloatIterator struct{}
func (*nilFloatIterator) Stats() IteratorStats { return IteratorStats{} }
func (*nilFloatIterator) Close() error { return nil }
func (*nilFloatIterator) Next() (*FloatPoint, error) { return nil, nil }
// integerFloatTransformIterator executes a function to modify an existing point for every
// output of the input iterator.
type integerFloatTransformIterator struct {
input IntegerIterator
fn integerFloatTransformFunc
}
// Stats returns stats from the input iterator.
func (itr *integerFloatTransformIterator) Stats() IteratorStats { return itr.input.Stats() }
// Close closes the iterator and all child iterators.
func (itr *integerFloatTransformIterator) Close() error { return itr.input.Close() }
// Next returns the minimum value for the next available interval.
func (itr *integerFloatTransformIterator) Next() (*FloatPoint, error) {
p, err := itr.input.Next()
if err != nil {
return nil, err
} else if p != nil {
return itr.fn(p), nil
}
return nil, nil
}
// integerFloatTransformFunc creates or modifies a point.
// The point passed in may be modified and returned rather than allocating a
// new point if possible.
type integerFloatTransformFunc func(p *IntegerPoint) *FloatPoint
type integerFloatCastIterator struct {
input IntegerIterator
}
func (itr *integerFloatCastIterator) Stats() IteratorStats { return itr.input.Stats() }
func (itr *integerFloatCastIterator) Close() error { return itr.input.Close() }
func (itr *integerFloatCastIterator) Next() (*FloatPoint, error) {
p, err := itr.input.Next()
if p == nil || err != nil {
return nil, err
}
return &FloatPoint{
Name: p.Name,
Tags: p.Tags,
Time: p.Time,
Nil: p.Nil,
Value: float64(p.Value),
Aux: p.Aux,
}, nil
}
// IteratorStats represents statistics about an iterator.
// Some statistics are available immediately upon iterator creation while
// some are derived as the iterator processes data.
type IteratorStats struct {
SeriesN int // series represented
PointN int // points returned
}
// Add aggregates fields from s and other together. Overwrites s.
func (s *IteratorStats) Add(other IteratorStats) {
s.SeriesN += other.SeriesN
s.PointN += other.PointN
}
func encodeIteratorStats(stats *IteratorStats) *internal.IteratorStats {
return &internal.IteratorStats{
SeriesN: proto.Int64(int64(stats.SeriesN)),
PointN: proto.Int64(int64(stats.PointN)),
}
}
func decodeIteratorStats(pb *internal.IteratorStats) IteratorStats {
return IteratorStats{
SeriesN: int(pb.GetSeriesN()),
PointN: int(pb.GetPointN()),
}
}
// floatFastDedupeIterator outputs unique points where the point has a single aux field.
type floatFastDedupeIterator struct {
input FloatIterator
m map[fastDedupeKey]struct{} // lookup of points already sent
}
// newFloatFastDedupeIterator returns a new instance of floatFastDedupeIterator.
func newFloatFastDedupeIterator(input FloatIterator) *floatFastDedupeIterator {
return &floatFastDedupeIterator{
input: input,
m: make(map[fastDedupeKey]struct{}),
}
}
// Stats returns stats from the input iterator.
func (itr *floatFastDedupeIterator) Stats() IteratorStats { return itr.input.Stats() }
// Close closes the iterator and all child iterators.
func (itr *floatFastDedupeIterator) Close() error { return itr.input.Close() }
// Next returns the next unique point from the input iterator.
func (itr *floatFastDedupeIterator) Next() (*FloatPoint, error) {
for {
// Read next point.
// Skip if there are not any aux fields.
p, err := itr.input.Next()
if p == nil || err != nil {
return nil, err
} else if len(p.Aux) == 0 {
continue
}
// If the point has already been output then move to the next point.
key := fastDedupeKey{name: p.Name}
key.values[0] = p.Aux[0]
if len(p.Aux) > 1 {
key.values[1] = p.Aux[1]
}
if _, ok := itr.m[key]; ok {
continue
}
// Otherwise mark it as emitted and return point.
itr.m[key] = struct{}{}
return p, nil
}
}
type fastDedupeKey struct {
name string
values [2]interface{}
}
type reverseStringSlice []string
func (p reverseStringSlice) Len() int { return len(p) }
func (p reverseStringSlice) Less(i, j int) bool { return p[i] > p[j] }
func (p reverseStringSlice) Swap(i, j int) { p[i], p[j] = p[j], p[i] }
func abs(v int64) int64 {
if v < 0 {
return -v
}
return v
}