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iterator.go
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iterator.go
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package query
import (
"context"
"encoding/binary"
"errors"
"fmt"
"io"
"regexp"
"time"
"github.com/gogo/protobuf/proto"
"github.com/influxdata/influxdb/pkg/tracing"
internal "github.com/influxdata/influxdb/query/internal"
"github.com/influxdata/influxql"
)
// ErrUnknownCall is returned when operating on an unknown function call.
var ErrUnknownCall = errors.New("unknown call")
const (
// 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
}
// dataType determines what slice type this set of iterators should be.
// An iterator type is chosen by looking at the first element in the slice
// and then returning the data type for that iterator.
func (a Iterators) dataType() influxql.DataType {
if len(a) == 0 {
return influxql.Unknown
}
switch a[0].(type) {
case FloatIterator:
return influxql.Float
case IntegerIterator:
return influxql.Integer
case UnsignedIterator:
return influxql.Unsigned
case StringIterator:
return influxql.String
case BooleanIterator:
return influxql.Boolean
default:
return influxql.Unknown
}
}
// coerce forces an array of iterators to be a single type.
// Iterators that are not of the same type as the first element in the slice
// will be closed and dropped.
func (a Iterators) coerce() interface{} {
typ := a.dataType()
switch typ {
case influxql.Float:
return newFloatIterators(a)
case influxql.Integer:
return newIntegerIterators(a)
case influxql.Unsigned:
return newUnsignedIterators(a)
case influxql.String:
return newStringIterators(a)
case influxql.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.(*influxql.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 = &influxql.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).coerce().(type) {
case []FloatIterator:
return newFloatMergeIterator(inputs, opt)
case []IntegerIterator:
return newIntegerMergeIterator(inputs, opt)
case []UnsignedIterator:
return newUnsignedMergeIterator(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).coerce().(type) {
case []FloatIterator:
return newFloatSortedMergeIterator(inputs, opt)
case []IntegerIterator:
return newIntegerSortedMergeIterator(inputs, opt)
case []UnsignedIterator:
return newUnsignedSortedMergeIterator(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 UnsignedIterator:
return newUnsignedParallelIterator(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 UnsignedIterator:
return newUnsignedLimitIterator(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 influxql.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 UnsignedIterator:
return newUnsignedFilterIterator(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))
}
}
// NewTagSubsetIterator will strip each of the points to a subset of the tag key values
// for each point it processes.
func NewTagSubsetIterator(input Iterator, opt IteratorOptions) Iterator {
if input == nil {
return nil
}
switch input := input.(type) {
case FloatIterator:
return newFloatTagSubsetIterator(input, opt)
case IntegerIterator:
return newIntegerTagSubsetIterator(input, opt)
case UnsignedIterator:
return newUnsignedTagSubsetIterator(input, opt)
case StringIterator:
return newStringTagSubsetIterator(input, opt)
case BooleanIterator:
return newBooleanTagSubsetIterator(input, opt)
default:
panic(fmt.Sprintf("unsupported tag subset 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 UnsignedIterator:
return newUnsignedDedupeIterator(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 influxql.Expr, opt IteratorOptions) Iterator {
switch input := input.(type) {
case FloatIterator:
return newFloatFillIterator(input, expr, opt)
case IntegerIterator:
return newIntegerFillIterator(input, expr, opt)
case UnsignedIterator:
return newUnsignedFillIterator(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 UnsignedIterator:
return newUnsignedIntervalIterator(input, opt)
case StringIterator:
return newStringIntervalIterator(input, opt)
case BooleanIterator:
return newBooleanIntervalIterator(input, opt)
default:
panic(fmt.Sprintf("unsupported interval 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 UnsignedIterator:
return newUnsignedInterruptIterator(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 UnsignedIterator:
return newUnsignedCloseInterruptIterator(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))
}
}
// IteratorScanner is used to scan the results of an iterator into a map.
type IteratorScanner interface {
// Peek retrieves information about the next point. It returns a timestamp, the name, and the tags.
Peek() (int64, string, Tags)
// ScanAt will take a time, name, and tags and scan the point that matches those into the map.
ScanAt(ts int64, name string, tags Tags, values map[string]interface{})
// Stats returns the IteratorStats from the Iterator.
Stats() IteratorStats
// Err returns an error that was encountered while scanning.
Err() error
io.Closer
}
// SkipDefault is a sentinel value to tell the IteratorScanner to skip setting the
// default value if none was present. This causes the map to use the previous value
// if it was previously set.
var SkipDefault = interface{}(0)
// NewIteratorScanner produces an IteratorScanner for the Iterator.
func NewIteratorScanner(input Iterator, keys []influxql.VarRef, defaultValue interface{}) IteratorScanner {
switch input := input.(type) {
case FloatIterator:
return newFloatIteratorScanner(input, keys, defaultValue)
case IntegerIterator:
return newIntegerIteratorScanner(input, keys, defaultValue)
case UnsignedIterator:
return newUnsignedIteratorScanner(input, keys, defaultValue)
case StringIterator:
return newStringIteratorScanner(input, keys, defaultValue)
case BooleanIterator:
return newBooleanIteratorScanner(input, keys, defaultValue)
default:
panic(fmt.Sprintf("unsupported type for iterator scanner: %T", input))
}
}
// 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 UnsignedIterator:
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 UnsignedIterator:
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(ctx context.Context, r io.Reader, typ influxql.DataType, stats IteratorStats) Iterator {
switch typ {
case influxql.Float:
return newFloatReaderIterator(ctx, r, stats)
case influxql.Integer:
return newIntegerReaderIterator(ctx, r, stats)
case influxql.Unsigned:
return newUnsignedReaderIterator(ctx, r, stats)
case influxql.String:
return newStringReaderIterator(ctx, r, stats)
case influxql.Boolean:
return newBooleanReaderIterator(ctx, r, stats)
default:
return &nilFloatReaderIterator{r: r}
}
}
// IteratorCreator is an interface to create Iterators.
type IteratorCreator interface {
// Creates a simple iterator for use in an InfluxQL query.
CreateIterator(ctx context.Context, source *influxql.Measurement, opt IteratorOptions) (Iterator, error)
// Determines the potential cost for creating an iterator.
IteratorCost(source *influxql.Measurement, opt IteratorOptions) (IteratorCost, error)
}
// 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 influxql.Expr
// Auxilary tags or values to also retrieve for the point.
Aux []influxql.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 []influxql.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 influxql.FillOption
FillValue interface{}
// Condition to filter by.
Condition influxql.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 the measurement name. Useful for meta queries.
StripName bool
// 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{}
// Authorizer can limit access to data
Authorizer Authorizer
}
// newIteratorOptionsStmt creates the iterator options from stmt.
func newIteratorOptionsStmt(stmt *influxql.SelectStatement, sopt SelectOptions) (opt IteratorOptions, err error) {
// Determine time range from the condition.
valuer := &influxql.NowValuer{Location: stmt.Location}
condition, timeRange, err := influxql.ConditionExpr(stmt.Condition, valuer)
if err != nil {
return IteratorOptions{}, err
}
if !timeRange.Min.IsZero() {
opt.StartTime = timeRange.Min.UnixNano()
} else {
opt.StartTime = influxql.MinTime
}
if !timeRange.Max.IsZero() {
opt.EndTime = timeRange.Max.UnixNano()
} else {
opt.EndTime = influxql.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.(*influxql.VarRef); ok {
opt.Dimensions = append(opt.Dimensions, d.Val)
opt.GroupBy[d.Val] = struct{}{}
}
}
opt.Condition = condition
opt.Ascending = stmt.TimeAscending()
opt.Dedupe = stmt.Dedupe
opt.StripName = stmt.StripName
opt.Fill, opt.FillValue = stmt.Fill, stmt.FillValue
if opt.Fill == influxql.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 = influxql.NoFill
}
opt.Limit, opt.Offset = stmt.Limit, stmt.Offset
opt.SLimit, opt.SOffset = stmt.SLimit, stmt.SOffset
opt.MaxSeriesN = sopt.MaxSeriesN
opt.Authorizer = sopt.Authorizer
return opt, nil
}
func newIteratorOptionsSubstatement(ctx context.Context, stmt *influxql.SelectStatement, opt IteratorOptions) (IteratorOptions, error) {
subOpt, err := newIteratorOptionsStmt(stmt, SelectOptions{
Authorizer: opt.Authorizer,
MaxSeriesN: opt.MaxSeriesN,
})
if err != nil {
return IteratorOptions{}, err
}
if subOpt.StartTime < opt.StartTime {
subOpt.StartTime = opt.StartTime
}
if subOpt.EndTime > opt.EndTime {
subOpt.EndTime = opt.EndTime
}
if !subOpt.Interval.IsZero() && subOpt.EndTime == influxql.MaxTime {
if now := ctx.Value("now"); now != nil {
subOpt.EndTime = now.(time.Time).UnixNano()
}
}
// Propagate the dimensions to the inner subquery.
subOpt.Dimensions = opt.Dimensions
for d := range opt.GroupBy {
subOpt.GroupBy[d] = struct{}{}
}
subOpt.InterruptCh = opt.InterruptCh
// Extract the time range and condition from the condition.
cond, t, err := influxql.ConditionExpr(stmt.Condition, nil)
if err != nil {
return IteratorOptions{}, err
}
subOpt.Condition = cond
// If the time range is more constrained, use it instead. A less constrained time
// range should be ignored.
if !t.Min.IsZero() && t.MinTimeNano() > opt.StartTime {
subOpt.StartTime = t.MinTimeNano()
}
if !t.Max.IsZero() && t.MaxTimeNano() < opt.EndTime {
subOpt.EndTime = t.MaxTimeNano()
}
// Propagate the SLIMIT and SOFFSET from the outer query.
subOpt.SLimit += opt.SLimit
subOpt.SOffset += opt.SOffset
// Propagate the ordering from the parent query.
subOpt.Ascending = opt.Ascending
// If the inner query uses a null fill option and is not a raw query,
// 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. We also do not do this for raw queries because
// there is no fill iterator for them and fill(none) doesn't work with
// raw queries.
if !stmt.IsRawQuery && subOpt.Fill == influxql.NullFill {
subOpt.Fill = influxql.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
}
// StopTime returns the time the iterator should end at.
// For ascending iterators this is the end time, for descending iterators it's the start time.
func (opt IteratorOptions) StopTime() int64 {
if opt.Ascending {
return opt.EndTime
}
return opt.StartTime
}
// 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 zone int64
if opt.Location != nil {
_, zone = opt.Zone(t)
}
// Truncate time by duration.
dt := (t + zone) % 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 influxql.MinTime+dt >= t {
start = influxql.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 {
_, startOffset := opt.Zone(start)
// Do not adjust the offset if the offset change is greater than or
// equal to the duration.
if o := zone - startOffset; o != 0 && abs(o) < int64(opt.Interval.Duration) {
start += o
}
}
start += int64(opt.Interval.Offset)
// Find the end time.
if dt := int64(opt.Interval.Duration) - dt; influxql.MaxTime-dt <= t {
end = influxql.MaxTime
} else {
end = t + dt
}
// 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.
// 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 o := zone - endOffset; o != 0 && abs(o) < int64(opt.Interval.Duration) {
// If the offset is greater than 0, that means we are adding time.
// Added time goes into the previous interval because the clocks
// move backwards. If the offset is less than 0, then we are skipping
// time. Skipped time comes after the switch so if we have a time
// interval that lands on the switch, it comes from the next
// interval and not the current one. For this reason, we need to know
// when the actual switch happens by seeing if the time switch is within
// the current interval. We calculate the zone offset with the offset
// and see if the value is the same. If it is, we apply the
// offset.
if o > 0 {
end += o
} else if _, z := opt.Zone(end + o); z == endOffset {
end += o
}
}
}
end += int64(opt.Interval.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.(*influxql.Call); ok && len(expr.Args) == 2 {
return Interval{Duration: expr.Args[1].(*influxql.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.(*influxql.Call); ok && len(expr.Args) == 2 {
return Interval{Duration: expr.Args[1].(*influxql.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.(*influxql.Call); ok && len(expr.Args) == 2 {
return Interval{Duration: expr.Args[1].(*influxql.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)),
StripName: proto.Bool(opt.StripName),
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.
if opt.Aux != nil {
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 opt.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.(*influxql.Measurement)
sources[i] = encodeMeasurement(mm)
}
pb.Sources = sources
}