prometheus/promql/engine.go
Tom Wilkie 4c52400708
Limit concurrent remote reads. (#4656)
Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
2018-09-25 20:07:34 +01:00

1733 lines
48 KiB
Go

// Copyright 2013 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package promql
import (
"container/heap"
"context"
"fmt"
"math"
"regexp"
"runtime"
"sort"
"strconv"
"sync"
"time"
"github.com/go-kit/kit/log"
"github.com/go-kit/kit/log/level"
opentracing "github.com/opentracing/opentracing-go"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/model"
"github.com/prometheus/prometheus/pkg/gate"
"github.com/prometheus/prometheus/pkg/labels"
"github.com/prometheus/prometheus/pkg/timestamp"
"github.com/prometheus/prometheus/pkg/value"
"github.com/prometheus/prometheus/storage"
"github.com/prometheus/prometheus/util/stats"
)
const (
namespace = "prometheus"
subsystem = "engine"
queryTag = "query"
// The largest SampleValue that can be converted to an int64 without overflow.
maxInt64 = 9223372036854774784
// The smallest SampleValue that can be converted to an int64 without underflow.
minInt64 = -9223372036854775808
)
type engineMetrics struct {
currentQueries prometheus.Gauge
maxConcurrentQueries prometheus.Gauge
queryQueueTime prometheus.Summary
queryPrepareTime prometheus.Summary
queryInnerEval prometheus.Summary
queryResultSort prometheus.Summary
}
// convertibleToInt64 returns true if v does not over-/underflow an int64.
func convertibleToInt64(v float64) bool {
return v <= maxInt64 && v >= minInt64
}
type (
// ErrQueryTimeout is returned if a query timed out during processing.
ErrQueryTimeout string
// ErrQueryCanceled is returned if a query was canceled during processing.
ErrQueryCanceled string
// ErrStorage is returned if an error was encountered in the storage layer
// during query handling.
ErrStorage error
)
func (e ErrQueryTimeout) Error() string { return fmt.Sprintf("query timed out in %s", string(e)) }
func (e ErrQueryCanceled) Error() string { return fmt.Sprintf("query was canceled in %s", string(e)) }
// A Query is derived from an a raw query string and can be run against an engine
// it is associated with.
type Query interface {
// Exec processes the query. Can only be called once.
Exec(ctx context.Context) *Result
// Close recovers memory used by the query result.
Close()
// Statement returns the parsed statement of the query.
Statement() Statement
// Stats returns statistics about the lifetime of the query.
Stats() *stats.QueryTimers
// Cancel signals that a running query execution should be aborted.
Cancel()
}
// query implements the Query interface.
type query struct {
// Underlying data provider.
queryable storage.Queryable
// The original query string.
q string
// Statement of the parsed query.
stmt Statement
// Timer stats for the query execution.
stats *stats.QueryTimers
// Result matrix for reuse.
matrix Matrix
// Cancellation function for the query.
cancel func()
// The engine against which the query is executed.
ng *Engine
}
// Statement implements the Query interface.
func (q *query) Statement() Statement {
return q.stmt
}
// Stats implements the Query interface.
func (q *query) Stats() *stats.QueryTimers {
return q.stats
}
// Cancel implements the Query interface.
func (q *query) Cancel() {
if q.cancel != nil {
q.cancel()
}
}
// Close implements the Query interface.
func (q *query) Close() {
for _, s := range q.matrix {
putPointSlice(s.Points)
}
}
// Exec implements the Query interface.
func (q *query) Exec(ctx context.Context) *Result {
if span := opentracing.SpanFromContext(ctx); span != nil {
span.SetTag(queryTag, q.stmt.String())
}
res, err := q.ng.exec(ctx, q)
return &Result{Err: err, Value: res}
}
// contextDone returns an error if the context was canceled or timed out.
func contextDone(ctx context.Context, env string) error {
select {
case <-ctx.Done():
return contextErr(ctx.Err(), env)
default:
return nil
}
}
func contextErr(err error, env string) error {
switch err {
case context.Canceled:
return ErrQueryCanceled(env)
case context.DeadlineExceeded:
return ErrQueryTimeout(env)
default:
return err
}
}
// Engine handles the lifetime of queries from beginning to end.
// It is connected to a querier.
type Engine struct {
logger log.Logger
metrics *engineMetrics
timeout time.Duration
gate *gate.Gate
}
// NewEngine returns a new engine.
func NewEngine(logger log.Logger, reg prometheus.Registerer, maxConcurrent int, timeout time.Duration) *Engine {
if logger == nil {
logger = log.NewNopLogger()
}
metrics := &engineMetrics{
currentQueries: prometheus.NewGauge(prometheus.GaugeOpts{
Namespace: namespace,
Subsystem: subsystem,
Name: "queries",
Help: "The current number of queries being executed or waiting.",
}),
maxConcurrentQueries: prometheus.NewGauge(prometheus.GaugeOpts{
Namespace: namespace,
Subsystem: subsystem,
Name: "queries_concurrent_max",
Help: "The max number of concurrent queries.",
}),
queryQueueTime: prometheus.NewSummary(prometheus.SummaryOpts{
Namespace: namespace,
Subsystem: subsystem,
Name: "query_duration_seconds",
Help: "Query timings",
ConstLabels: prometheus.Labels{"slice": "queue_time"},
}),
queryPrepareTime: prometheus.NewSummary(prometheus.SummaryOpts{
Namespace: namespace,
Subsystem: subsystem,
Name: "query_duration_seconds",
Help: "Query timings",
ConstLabels: prometheus.Labels{"slice": "prepare_time"},
}),
queryInnerEval: prometheus.NewSummary(prometheus.SummaryOpts{
Namespace: namespace,
Subsystem: subsystem,
Name: "query_duration_seconds",
Help: "Query timings",
ConstLabels: prometheus.Labels{"slice": "inner_eval"},
}),
queryResultSort: prometheus.NewSummary(prometheus.SummaryOpts{
Namespace: namespace,
Subsystem: subsystem,
Name: "query_duration_seconds",
Help: "Query timings",
ConstLabels: prometheus.Labels{"slice": "result_sort"},
}),
}
metrics.maxConcurrentQueries.Set(float64(maxConcurrent))
if reg != nil {
reg.MustRegister(
metrics.currentQueries,
metrics.maxConcurrentQueries,
metrics.queryQueueTime,
metrics.queryPrepareTime,
metrics.queryInnerEval,
metrics.queryResultSort,
)
}
return &Engine{
gate: gate.New(maxConcurrent),
timeout: timeout,
logger: logger,
metrics: metrics,
}
}
// NewInstantQuery returns an evaluation query for the given expression at the given time.
func (ng *Engine) NewInstantQuery(q storage.Queryable, qs string, ts time.Time) (Query, error) {
expr, err := ParseExpr(qs)
if err != nil {
return nil, err
}
qry := ng.newQuery(q, expr, ts, ts, 0)
qry.q = qs
return qry, nil
}
// NewRangeQuery returns an evaluation query for the given time range and with
// the resolution set by the interval.
func (ng *Engine) NewRangeQuery(q storage.Queryable, qs string, start, end time.Time, interval time.Duration) (Query, error) {
expr, err := ParseExpr(qs)
if err != nil {
return nil, err
}
if expr.Type() != ValueTypeVector && expr.Type() != ValueTypeScalar {
return nil, fmt.Errorf("invalid expression type %q for range query, must be Scalar or instant Vector", documentedType(expr.Type()))
}
qry := ng.newQuery(q, expr, start, end, interval)
qry.q = qs
return qry, nil
}
func (ng *Engine) newQuery(q storage.Queryable, expr Expr, start, end time.Time, interval time.Duration) *query {
es := &EvalStmt{
Expr: expr,
Start: start,
End: end,
Interval: interval,
}
qry := &query{
stmt: es,
ng: ng,
stats: stats.NewQueryTimers(),
queryable: q,
}
return qry
}
// testStmt is an internal helper statement that allows execution
// of an arbitrary function during handling. It is used to test the Engine.
type testStmt func(context.Context) error
func (testStmt) String() string { return "test statement" }
func (testStmt) stmt() {}
func (ng *Engine) newTestQuery(f func(context.Context) error) Query {
qry := &query{
q: "test statement",
stmt: testStmt(f),
ng: ng,
stats: stats.NewQueryTimers(),
}
return qry
}
// exec executes the query.
//
// At this point per query only one EvalStmt is evaluated. Alert and record
// statements are not handled by the Engine.
func (ng *Engine) exec(ctx context.Context, q *query) (Value, error) {
ng.metrics.currentQueries.Inc()
defer ng.metrics.currentQueries.Dec()
ctx, cancel := context.WithTimeout(ctx, ng.timeout)
q.cancel = cancel
execSpanTimer, ctx := q.stats.GetSpanTimer(ctx, stats.ExecTotalTime)
defer execSpanTimer.Finish()
queueSpanTimer, _ := q.stats.GetSpanTimer(ctx, stats.ExecQueueTime, ng.metrics.queryQueueTime)
if err := ng.gate.Start(ctx); err != nil {
return nil, contextErr(err, "query queue")
}
defer ng.gate.Done()
queueSpanTimer.Finish()
// Cancel when execution is done or an error was raised.
defer q.cancel()
const env = "query execution"
evalSpanTimer, ctx := q.stats.GetSpanTimer(ctx, stats.EvalTotalTime)
defer evalSpanTimer.Finish()
// The base context might already be canceled on the first iteration (e.g. during shutdown).
if err := contextDone(ctx, env); err != nil {
return nil, err
}
switch s := q.Statement().(type) {
case *EvalStmt:
return ng.execEvalStmt(ctx, q, s)
case testStmt:
return nil, s(ctx)
}
panic(fmt.Errorf("promql.Engine.exec: unhandled statement of type %T", q.Statement()))
}
func timeMilliseconds(t time.Time) int64 {
return t.UnixNano() / int64(time.Millisecond/time.Nanosecond)
}
func durationMilliseconds(d time.Duration) int64 {
return int64(d / (time.Millisecond / time.Nanosecond))
}
// execEvalStmt evaluates the expression of an evaluation statement for the given time range.
func (ng *Engine) execEvalStmt(ctx context.Context, query *query, s *EvalStmt) (Value, error) {
prepareSpanTimer, ctxPrepare := query.stats.GetSpanTimer(ctx, stats.QueryPreparationTime, ng.metrics.queryPrepareTime)
querier, err := ng.populateSeries(ctxPrepare, query.queryable, s)
prepareSpanTimer.Finish()
// XXX(fabxc): the querier returned by populateSeries might be instantiated
// we must not return without closing irrespective of the error.
// TODO: make this semantically saner.
if querier != nil {
defer querier.Close()
}
if err != nil {
return nil, err
}
evalSpanTimer, _ := query.stats.GetSpanTimer(ctx, stats.InnerEvalTime, ng.metrics.queryInnerEval)
// Instant evaluation. This is executed as a range evaluation with one step.
if s.Start == s.End && s.Interval == 0 {
start := timeMilliseconds(s.Start)
evaluator := &evaluator{
startTimestamp: start,
endTimestamp: start,
interval: 1,
ctx: ctx,
logger: ng.logger,
}
val, err := evaluator.Eval(s.Expr)
if err != nil {
return nil, err
}
evalSpanTimer.Finish()
mat, ok := val.(Matrix)
if !ok {
panic(fmt.Errorf("promql.Engine.exec: invalid expression type %q", val.Type()))
}
query.matrix = mat
switch s.Expr.Type() {
case ValueTypeVector:
// Convert matrix with one value per series into vector.
vector := make(Vector, len(mat))
for i, s := range mat {
// Point might have a different timestamp, force it to the evaluation
// timestamp as that is when we ran the evaluation.
vector[i] = Sample{Metric: s.Metric, Point: Point{V: s.Points[0].V, T: start}}
}
return vector, nil
case ValueTypeScalar:
return Scalar{V: mat[0].Points[0].V, T: start}, nil
case ValueTypeMatrix:
return mat, nil
default:
panic(fmt.Errorf("promql.Engine.exec: unexpected expression type %q", s.Expr.Type()))
}
}
// Range evaluation.
evaluator := &evaluator{
startTimestamp: timeMilliseconds(s.Start),
endTimestamp: timeMilliseconds(s.End),
interval: durationMilliseconds(s.Interval),
ctx: ctx,
logger: ng.logger,
}
val, err := evaluator.Eval(s.Expr)
if err != nil {
return nil, err
}
evalSpanTimer.Finish()
mat, ok := val.(Matrix)
if !ok {
panic(fmt.Errorf("promql.Engine.exec: invalid expression type %q", val.Type()))
}
query.matrix = mat
if err := contextDone(ctx, "expression evaluation"); err != nil {
return nil, err
}
// TODO(fabxc): order ensured by storage?
// TODO(fabxc): where to ensure metric labels are a copy from the storage internals.
sortSpanTimer, _ := query.stats.GetSpanTimer(ctx, stats.ResultSortTime, ng.metrics.queryResultSort)
sort.Sort(mat)
sortSpanTimer.Finish()
return mat, nil
}
func (ng *Engine) populateSeries(ctx context.Context, q storage.Queryable, s *EvalStmt) (storage.Querier, error) {
var maxOffset time.Duration
Inspect(s.Expr, func(node Node, _ []Node) error {
switch n := node.(type) {
case *VectorSelector:
if maxOffset < LookbackDelta {
maxOffset = LookbackDelta
}
if n.Offset+LookbackDelta > maxOffset {
maxOffset = n.Offset + LookbackDelta
}
case *MatrixSelector:
if maxOffset < n.Range {
maxOffset = n.Range
}
if n.Offset+n.Range > maxOffset {
maxOffset = n.Offset + n.Range
}
}
return nil
})
mint := s.Start.Add(-maxOffset)
querier, err := q.Querier(ctx, timestamp.FromTime(mint), timestamp.FromTime(s.End))
if err != nil {
return nil, err
}
Inspect(s.Expr, func(node Node, path []Node) error {
var set storage.SeriesSet
params := &storage.SelectParams{
Start: timestamp.FromTime(s.Start),
End: timestamp.FromTime(s.End),
Step: int64(s.Interval / time.Millisecond),
}
switch n := node.(type) {
case *VectorSelector:
params.Start = params.Start - durationMilliseconds(LookbackDelta)
params.Func = extractFuncFromPath(path)
if n.Offset > 0 {
offsetMilliseconds := durationMilliseconds(n.Offset)
params.Start = params.Start - offsetMilliseconds
params.End = params.End - offsetMilliseconds
}
set, err = querier.Select(params, n.LabelMatchers...)
if err != nil {
level.Error(ng.logger).Log("msg", "error selecting series set", "err", err)
return err
}
n.series, err = expandSeriesSet(ctx, set)
if err != nil {
// TODO(fabxc): use multi-error.
level.Error(ng.logger).Log("msg", "error expanding series set", "err", err)
return err
}
case *MatrixSelector:
params.Func = extractFuncFromPath(path)
// For all matrix queries we want to ensure that we have (end-start) + range selected
// this way we have `range` data before the start time
params.Start = params.Start - durationMilliseconds(n.Range)
if n.Offset > 0 {
offsetMilliseconds := durationMilliseconds(n.Offset)
params.Start = params.Start - offsetMilliseconds
params.End = params.End - offsetMilliseconds
}
set, err = querier.Select(params, n.LabelMatchers...)
if err != nil {
level.Error(ng.logger).Log("msg", "error selecting series set", "err", err)
return err
}
n.series, err = expandSeriesSet(ctx, set)
if err != nil {
level.Error(ng.logger).Log("msg", "error expanding series set", "err", err)
return err
}
}
return nil
})
return querier, err
}
// extractFuncFromPath walks up the path and searches for the first instance of
// a function or aggregation.
func extractFuncFromPath(p []Node) string {
if len(p) == 0 {
return ""
}
switch n := p[len(p)-1].(type) {
case *AggregateExpr:
return n.Op.String()
case *Call:
return n.Func.Name
case *BinaryExpr:
// If we hit a binary expression we terminate since we only care about functions
// or aggregations over a single metric.
return ""
}
return extractFuncFromPath(p[:len(p)-1])
}
func expandSeriesSet(ctx context.Context, it storage.SeriesSet) (res []storage.Series, err error) {
for it.Next() {
select {
case <-ctx.Done():
return nil, ctx.Err()
default:
}
res = append(res, it.At())
}
return res, it.Err()
}
// An evaluator evaluates given expressions over given fixed timestamps. It
// is attached to an engine through which it connects to a querier and reports
// errors. On timeout or cancellation of its context it terminates.
type evaluator struct {
ctx context.Context
startTimestamp int64 // Start time in milliseconds.
endTimestamp int64 // End time in milliseconds.
interval int64 // Interval in milliseconds.
logger log.Logger
}
// errorf causes a panic with the input formatted into an error.
func (ev *evaluator) errorf(format string, args ...interface{}) {
ev.error(fmt.Errorf(format, args...))
}
// error causes a panic with the given error.
func (ev *evaluator) error(err error) {
panic(err)
}
// recover is the handler that turns panics into returns from the top level of evaluation.
func (ev *evaluator) recover(errp *error) {
e := recover()
if e == nil {
return
}
if err, ok := e.(runtime.Error); ok {
// Print the stack trace but do not inhibit the running application.
buf := make([]byte, 64<<10)
buf = buf[:runtime.Stack(buf, false)]
level.Error(ev.logger).Log("msg", "runtime panic in parser", "err", e, "stacktrace", string(buf))
*errp = fmt.Errorf("unexpected error: %s", err)
} else {
*errp = e.(error)
}
}
func (ev *evaluator) Eval(expr Expr) (v Value, err error) {
defer ev.recover(&err)
return ev.eval(expr), nil
}
// EvalNodeHelper stores extra information and caches for evaluating a single node across steps.
type EvalNodeHelper struct {
// Evaluation timestamp.
ts int64
// Vector that can be used for output.
out Vector
// Caches.
// dropMetricName and label_*.
dmn map[uint64]labels.Labels
// signatureFunc.
sigf map[uint64]uint64
// funcHistogramQuantile.
signatureToMetricWithBuckets map[uint64]*metricWithBuckets
// label_replace.
regex *regexp.Regexp
// For binary vector matching.
rightSigs map[uint64]Sample
matchedSigs map[uint64]map[uint64]struct{}
resultMetric map[uint64]labels.Labels
}
// dropMetricName is a cached version of dropMetricName.
func (enh *EvalNodeHelper) dropMetricName(l labels.Labels) labels.Labels {
if enh.dmn == nil {
enh.dmn = make(map[uint64]labels.Labels, len(enh.out))
}
h := l.Hash()
ret, ok := enh.dmn[h]
if ok {
return ret
}
ret = dropMetricName(l)
enh.dmn[h] = ret
return ret
}
// signatureFunc is a cached version of signatureFunc.
func (enh *EvalNodeHelper) signatureFunc(on bool, names ...string) func(labels.Labels) uint64 {
if enh.sigf == nil {
enh.sigf = make(map[uint64]uint64, len(enh.out))
}
f := signatureFunc(on, names...)
return func(l labels.Labels) uint64 {
h := l.Hash()
ret, ok := enh.sigf[h]
if ok {
return ret
}
ret = f(l)
enh.sigf[h] = ret
return ret
}
}
// rangeEval evaluates the given expressions, and then for each step calls
// the given function with the values computed for each expression at that
// step. The return value is the combination into time series of of all the
// function call results.
func (ev *evaluator) rangeEval(f func([]Value, *EvalNodeHelper) Vector, exprs ...Expr) Matrix {
numSteps := int((ev.endTimestamp-ev.startTimestamp)/ev.interval) + 1
matrixes := make([]Matrix, len(exprs))
origMatrixes := make([]Matrix, len(exprs))
for i, e := range exprs {
// Functions will take string arguments from the expressions, not the values.
if e != nil && e.Type() != ValueTypeString {
matrixes[i] = ev.eval(e).(Matrix)
// Keep a copy of the original point slices so that they
// can be returned to the pool.
origMatrixes[i] = make(Matrix, len(matrixes[i]))
copy(origMatrixes[i], matrixes[i])
}
}
vectors := make([]Vector, len(exprs)) // Input vectors for the function.
args := make([]Value, len(exprs)) // Argument to function.
// Create an output vector that is as big as the input matrix with
// the most time series.
biggestLen := 1
for i := range exprs {
vectors[i] = make(Vector, 0, len(matrixes[i]))
if len(matrixes[i]) > biggestLen {
biggestLen = len(matrixes[i])
}
}
enh := &EvalNodeHelper{out: make(Vector, 0, biggestLen)}
seriess := make(map[uint64]Series, biggestLen) // Output series by series hash.
for ts := ev.startTimestamp; ts <= ev.endTimestamp; ts += ev.interval {
// Gather input vectors for this timestamp.
for i := range exprs {
vectors[i] = vectors[i][:0]
for si, series := range matrixes[i] {
for _, point := range series.Points {
if point.T == ts {
vectors[i] = append(vectors[i], Sample{Metric: series.Metric, Point: point})
// Move input vectors forward so we don't have to re-scan the same
// past points at the next step.
matrixes[i][si].Points = series.Points[1:]
}
break
}
}
args[i] = vectors[i]
}
// Make the function call.
enh.ts = ts
result := f(args, enh)
if result.ContainsSameLabelset() {
ev.errorf("vector cannot contain metrics with the same labelset")
}
enh.out = result[:0] // Reuse result vector.
// If this could be an instant query, shortcut so as not to change sort order.
if ev.endTimestamp == ev.startTimestamp {
mat := make(Matrix, len(result))
for i, s := range result {
s.Point.T = ts
mat[i] = Series{Metric: s.Metric, Points: []Point{s.Point}}
}
return mat
}
// Add samples in output vector to output series.
for _, sample := range result {
h := sample.Metric.Hash()
ss, ok := seriess[h]
if !ok {
ss = Series{
Metric: sample.Metric,
Points: getPointSlice(numSteps),
}
}
sample.Point.T = ts
ss.Points = append(ss.Points, sample.Point)
seriess[h] = ss
}
}
// Reuse the original point slices.
for _, m := range origMatrixes {
for _, s := range m {
putPointSlice(s.Points)
}
}
// Assemble the output matrix.
mat := make(Matrix, 0, len(seriess))
for _, ss := range seriess {
mat = append(mat, ss)
}
return mat
}
// eval evaluates the given expression as the given AST expression node requires.
func (ev *evaluator) eval(expr Expr) Value {
// This is the top-level evaluation method.
// Thus, we check for timeout/cancellation here.
if err := contextDone(ev.ctx, "expression evaluation"); err != nil {
ev.error(err)
}
numSteps := int((ev.endTimestamp-ev.startTimestamp)/ev.interval) + 1
switch e := expr.(type) {
case *AggregateExpr:
if s, ok := e.Param.(*StringLiteral); ok {
return ev.rangeEval(func(v []Value, enh *EvalNodeHelper) Vector {
return ev.aggregation(e.Op, e.Grouping, e.Without, s.Val, v[0].(Vector), enh)
}, e.Expr)
}
return ev.rangeEval(func(v []Value, enh *EvalNodeHelper) Vector {
var param float64
if e.Param != nil {
param = v[0].(Vector)[0].V
}
return ev.aggregation(e.Op, e.Grouping, e.Without, param, v[1].(Vector), enh)
}, e.Param, e.Expr)
case *Call:
if e.Func.Name == "timestamp" {
// Matrix evaluation always returns the evaluation time,
// so this function needs special handling when given
// a vector selector.
vs, ok := e.Args[0].(*VectorSelector)
if ok {
return ev.rangeEval(func(v []Value, enh *EvalNodeHelper) Vector {
return e.Func.Call([]Value{ev.vectorSelector(vs, enh.ts)}, e.Args, enh)
})
}
}
// Check if the function has a matrix argument.
var matrixArgIndex int
var matrixArg bool
for i, a := range e.Args {
_, ok := a.(*MatrixSelector)
if ok {
matrixArgIndex = i
matrixArg = true
break
}
}
if !matrixArg {
// Does not have a matrix argument.
return ev.rangeEval(func(v []Value, enh *EvalNodeHelper) Vector {
return e.Func.Call(v, e.Args, enh)
}, e.Args...)
}
inArgs := make([]Value, len(e.Args))
// Evaluate any non-matrix arguments.
otherArgs := make([]Matrix, len(e.Args))
otherInArgs := make([]Vector, len(e.Args))
for i, e := range e.Args {
if i != matrixArgIndex {
otherArgs[i] = ev.eval(e).(Matrix)
otherInArgs[i] = Vector{Sample{}}
inArgs[i] = otherInArgs[i]
}
}
sel := e.Args[matrixArgIndex].(*MatrixSelector)
mat := make(Matrix, 0, len(sel.series)) // Output matrix.
offset := durationMilliseconds(sel.Offset)
selRange := durationMilliseconds(sel.Range)
stepRange := selRange
if stepRange > ev.interval {
stepRange = ev.interval
}
// Reuse objects across steps to save memory allocations.
points := getPointSlice(16)
inMatrix := make(Matrix, 1)
inArgs[matrixArgIndex] = inMatrix
enh := &EvalNodeHelper{out: make(Vector, 0, 1)}
// Process all the calls for one time series at a time.
it := storage.NewBuffer(selRange)
for i, s := range sel.series {
points = points[:0]
it.Reset(s.Iterator())
ss := Series{
// For all range vector functions, the only change to the
// output labels is dropping the metric name so just do
// it once here.
Metric: dropMetricName(sel.series[i].Labels()),
Points: getPointSlice(numSteps),
}
inMatrix[0].Metric = sel.series[i].Labels()
for ts, step := ev.startTimestamp, -1; ts <= ev.endTimestamp; ts += ev.interval {
step++
// Set the non-matrix arguments.
// They are scalar, so it is safe to use the step number
// when looking up the argument, as there will be no gaps.
for j := range e.Args {
if j != matrixArgIndex {
otherInArgs[j][0].V = otherArgs[j][0].Points[step].V
}
}
maxt := ts - offset
mint := maxt - selRange
// Evaluate the matrix selector for this series for this step.
points = ev.matrixIterSlice(it, mint, maxt, points)
if len(points) == 0 {
continue
}
inMatrix[0].Points = points
enh.ts = ts
// Make the function call.
outVec := e.Func.Call(inArgs, e.Args, enh)
enh.out = outVec[:0]
if len(outVec) > 0 {
ss.Points = append(ss.Points, Point{V: outVec[0].Point.V, T: ts})
}
// Only buffer stepRange milliseconds from the second step on.
it.ReduceDelta(stepRange)
}
if len(ss.Points) > 0 {
mat = append(mat, ss)
}
}
if mat.ContainsSameLabelset() {
ev.errorf("vector cannot contain metrics with the same labelset")
}
putPointSlice(points)
return mat
case *ParenExpr:
return ev.eval(e.Expr)
case *UnaryExpr:
mat := ev.eval(e.Expr).(Matrix)
if e.Op == itemSUB {
for i := range mat {
mat[i].Metric = dropMetricName(mat[i].Metric)
for j := range mat[i].Points {
mat[i].Points[j].V = -mat[i].Points[j].V
}
}
if mat.ContainsSameLabelset() {
ev.errorf("vector cannot contain metrics with the same labelset")
}
}
return mat
case *BinaryExpr:
switch lt, rt := e.LHS.Type(), e.RHS.Type(); {
case lt == ValueTypeScalar && rt == ValueTypeScalar:
return ev.rangeEval(func(v []Value, enh *EvalNodeHelper) Vector {
val := scalarBinop(e.Op, v[0].(Vector)[0].Point.V, v[1].(Vector)[0].Point.V)
return append(enh.out, Sample{Point: Point{V: val}})
}, e.LHS, e.RHS)
case lt == ValueTypeVector && rt == ValueTypeVector:
switch e.Op {
case itemLAND:
return ev.rangeEval(func(v []Value, enh *EvalNodeHelper) Vector {
return ev.VectorAnd(v[0].(Vector), v[1].(Vector), e.VectorMatching, enh)
}, e.LHS, e.RHS)
case itemLOR:
return ev.rangeEval(func(v []Value, enh *EvalNodeHelper) Vector {
return ev.VectorOr(v[0].(Vector), v[1].(Vector), e.VectorMatching, enh)
}, e.LHS, e.RHS)
case itemLUnless:
return ev.rangeEval(func(v []Value, enh *EvalNodeHelper) Vector {
return ev.VectorUnless(v[0].(Vector), v[1].(Vector), e.VectorMatching, enh)
}, e.LHS, e.RHS)
default:
return ev.rangeEval(func(v []Value, enh *EvalNodeHelper) Vector {
return ev.VectorBinop(e.Op, v[0].(Vector), v[1].(Vector), e.VectorMatching, e.ReturnBool, enh)
}, e.LHS, e.RHS)
}
case lt == ValueTypeVector && rt == ValueTypeScalar:
return ev.rangeEval(func(v []Value, enh *EvalNodeHelper) Vector {
return ev.VectorscalarBinop(e.Op, v[0].(Vector), Scalar{V: v[1].(Vector)[0].Point.V}, false, e.ReturnBool, enh)
}, e.LHS, e.RHS)
case lt == ValueTypeScalar && rt == ValueTypeVector:
return ev.rangeEval(func(v []Value, enh *EvalNodeHelper) Vector {
return ev.VectorscalarBinop(e.Op, v[1].(Vector), Scalar{V: v[0].(Vector)[0].Point.V}, true, e.ReturnBool, enh)
}, e.LHS, e.RHS)
}
case *NumberLiteral:
return ev.rangeEval(func(v []Value, enh *EvalNodeHelper) Vector {
return append(enh.out, Sample{Point: Point{V: e.Val}})
})
case *VectorSelector:
mat := make(Matrix, 0, len(e.series))
it := storage.NewBuffer(durationMilliseconds(LookbackDelta))
for i, s := range e.series {
it.Reset(s.Iterator())
ss := Series{
Metric: e.series[i].Labels(),
Points: getPointSlice(numSteps),
}
for ts := ev.startTimestamp; ts <= ev.endTimestamp; ts += ev.interval {
_, v, ok := ev.vectorSelectorSingle(it, e, ts)
if ok {
ss.Points = append(ss.Points, Point{V: v, T: ts})
}
}
if len(ss.Points) > 0 {
mat = append(mat, ss)
}
}
return mat
case *MatrixSelector:
if ev.startTimestamp != ev.endTimestamp {
panic(fmt.Errorf("cannot do range evaluation of matrix selector"))
}
return ev.matrixSelector(e)
}
panic(fmt.Errorf("unhandled expression of type: %T", expr))
}
// vectorSelector evaluates a *VectorSelector expression.
func (ev *evaluator) vectorSelector(node *VectorSelector, ts int64) Vector {
var (
vec = make(Vector, 0, len(node.series))
)
it := storage.NewBuffer(durationMilliseconds(LookbackDelta))
for i, s := range node.series {
it.Reset(s.Iterator())
t, v, ok := ev.vectorSelectorSingle(it, node, ts)
if ok {
vec = append(vec, Sample{
Metric: node.series[i].Labels(),
Point: Point{V: v, T: t},
})
}
}
return vec
}
// vectorSelectorSingle evaluates a instant vector for the iterator of one time series.
func (ev *evaluator) vectorSelectorSingle(it *storage.BufferedSeriesIterator, node *VectorSelector, ts int64) (int64, float64, bool) {
refTime := ts - durationMilliseconds(node.Offset)
var t int64
var v float64
ok := it.Seek(refTime)
if !ok {
if it.Err() != nil {
ev.error(it.Err())
}
}
if ok {
t, v = it.Values()
}
if !ok || t > refTime {
t, v, ok = it.PeekBack(1)
if !ok || t < refTime-durationMilliseconds(LookbackDelta) {
return 0, 0, false
}
}
if value.IsStaleNaN(v) {
return 0, 0, false
}
return t, v, true
}
var pointPool = sync.Pool{}
func getPointSlice(sz int) []Point {
p := pointPool.Get()
if p != nil {
return p.([]Point)
}
return make([]Point, 0, sz)
}
func putPointSlice(p []Point) {
pointPool.Put(p[:0])
}
// matrixSelector evaluates a *MatrixSelector expression.
func (ev *evaluator) matrixSelector(node *MatrixSelector) Matrix {
var (
offset = durationMilliseconds(node.Offset)
maxt = ev.startTimestamp - offset
mint = maxt - durationMilliseconds(node.Range)
matrix = make(Matrix, 0, len(node.series))
)
it := storage.NewBuffer(durationMilliseconds(node.Range))
for i, s := range node.series {
if err := contextDone(ev.ctx, "expression evaluation"); err != nil {
ev.error(err)
}
it.Reset(s.Iterator())
ss := Series{
Metric: node.series[i].Labels(),
}
ss.Points = ev.matrixIterSlice(it, mint, maxt, getPointSlice(16))
if len(ss.Points) > 0 {
matrix = append(matrix, ss)
} else {
putPointSlice(ss.Points)
}
}
return matrix
}
// matrixIterSlice populates a matrix vector covering the requested range for a
// single time series, with points retrieved from an iterator.
//
// As an optimization, the matrix vector may already contain points of the same
// time series from the evaluation of an earlier step (with lower mint and maxt
// values). Any such points falling before mint are discarded; points that fall
// into the [mint, maxt] range are retained; only points with later timestamps
// are populated from the iterator.
func (ev *evaluator) matrixIterSlice(it *storage.BufferedSeriesIterator, mint, maxt int64, out []Point) []Point {
if len(out) > 0 && out[len(out)-1].T >= mint {
// There is an overlap between previous and current ranges, retain common
// points. In most such cases:
// (a) the overlap is significantly larger than the eval step; and/or
// (b) the number of samples is relatively small.
// so a linear search will be as fast as a binary search.
var drop int
for drop = 0; out[drop].T < mint; drop++ {
}
copy(out, out[drop:])
out = out[:len(out)-drop]
// Only append points with timestamps after the last timestamp we have.
mint = out[len(out)-1].T + 1
} else {
out = out[:0]
}
ok := it.Seek(maxt)
if !ok {
if it.Err() != nil {
ev.error(it.Err())
}
}
buf := it.Buffer()
for buf.Next() {
t, v := buf.At()
if value.IsStaleNaN(v) {
continue
}
// Values in the buffer are guaranteed to be smaller than maxt.
if t >= mint {
out = append(out, Point{T: t, V: v})
}
}
// The seeked sample might also be in the range.
if ok {
t, v := it.Values()
if t == maxt && !value.IsStaleNaN(v) {
out = append(out, Point{T: t, V: v})
}
}
return out
}
func (ev *evaluator) VectorAnd(lhs, rhs Vector, matching *VectorMatching, enh *EvalNodeHelper) Vector {
if matching.Card != CardManyToMany {
panic("set operations must only use many-to-many matching")
}
sigf := enh.signatureFunc(matching.On, matching.MatchingLabels...)
// The set of signatures for the right-hand side Vector.
rightSigs := map[uint64]struct{}{}
// Add all rhs samples to a map so we can easily find matches later.
for _, rs := range rhs {
rightSigs[sigf(rs.Metric)] = struct{}{}
}
for _, ls := range lhs {
// If there's a matching entry in the right-hand side Vector, add the sample.
if _, ok := rightSigs[sigf(ls.Metric)]; ok {
enh.out = append(enh.out, ls)
}
}
return enh.out
}
func (ev *evaluator) VectorOr(lhs, rhs Vector, matching *VectorMatching, enh *EvalNodeHelper) Vector {
if matching.Card != CardManyToMany {
panic("set operations must only use many-to-many matching")
}
sigf := enh.signatureFunc(matching.On, matching.MatchingLabels...)
leftSigs := map[uint64]struct{}{}
// Add everything from the left-hand-side Vector.
for _, ls := range lhs {
leftSigs[sigf(ls.Metric)] = struct{}{}
enh.out = append(enh.out, ls)
}
// Add all right-hand side elements which have not been added from the left-hand side.
for _, rs := range rhs {
if _, ok := leftSigs[sigf(rs.Metric)]; !ok {
enh.out = append(enh.out, rs)
}
}
return enh.out
}
func (ev *evaluator) VectorUnless(lhs, rhs Vector, matching *VectorMatching, enh *EvalNodeHelper) Vector {
if matching.Card != CardManyToMany {
panic("set operations must only use many-to-many matching")
}
sigf := enh.signatureFunc(matching.On, matching.MatchingLabels...)
rightSigs := map[uint64]struct{}{}
for _, rs := range rhs {
rightSigs[sigf(rs.Metric)] = struct{}{}
}
for _, ls := range lhs {
if _, ok := rightSigs[sigf(ls.Metric)]; !ok {
enh.out = append(enh.out, ls)
}
}
return enh.out
}
// VectorBinop evaluates a binary operation between two Vectors, excluding set operators.
func (ev *evaluator) VectorBinop(op ItemType, lhs, rhs Vector, matching *VectorMatching, returnBool bool, enh *EvalNodeHelper) Vector {
if matching.Card == CardManyToMany {
panic("many-to-many only allowed for set operators")
}
sigf := enh.signatureFunc(matching.On, matching.MatchingLabels...)
// The control flow below handles one-to-one or many-to-one matching.
// For one-to-many, swap sidedness and account for the swap when calculating
// values.
if matching.Card == CardOneToMany {
lhs, rhs = rhs, lhs
}
// All samples from the rhs hashed by the matching label/values.
if enh.rightSigs == nil {
enh.rightSigs = make(map[uint64]Sample, len(enh.out))
} else {
for k := range enh.rightSigs {
delete(enh.rightSigs, k)
}
}
rightSigs := enh.rightSigs
// Add all rhs samples to a map so we can easily find matches later.
for _, rs := range rhs {
sig := sigf(rs.Metric)
// The rhs is guaranteed to be the 'one' side. Having multiple samples
// with the same signature means that the matching is many-to-many.
if _, found := rightSigs[sig]; found {
// Many-to-many matching not allowed.
ev.errorf("many-to-many matching not allowed: matching labels must be unique on one side")
}
rightSigs[sig] = rs
}
// Tracks the match-signature. For one-to-one operations the value is nil. For many-to-one
// the value is a set of signatures to detect duplicated result elements.
if enh.matchedSigs == nil {
enh.matchedSigs = make(map[uint64]map[uint64]struct{}, len(rightSigs))
} else {
for k := range enh.matchedSigs {
delete(enh.matchedSigs, k)
}
}
matchedSigs := enh.matchedSigs
// For all lhs samples find a respective rhs sample and perform
// the binary operation.
for _, ls := range lhs {
sig := sigf(ls.Metric)
rs, found := rightSigs[sig] // Look for a match in the rhs Vector.
if !found {
continue
}
// Account for potentially swapped sidedness.
vl, vr := ls.V, rs.V
if matching.Card == CardOneToMany {
vl, vr = vr, vl
}
value, keep := vectorElemBinop(op, vl, vr)
if returnBool {
if keep {
value = 1.0
} else {
value = 0.0
}
} else if !keep {
continue
}
metric := resultMetric(ls.Metric, rs.Metric, op, matching, enh)
insertedSigs, exists := matchedSigs[sig]
if matching.Card == CardOneToOne {
if exists {
ev.errorf("multiple matches for labels: many-to-one matching must be explicit (group_left/group_right)")
}
matchedSigs[sig] = nil // Set existence to true.
} else {
// In many-to-one matching the grouping labels have to ensure a unique metric
// for the result Vector. Check whether those labels have already been added for
// the same matching labels.
insertSig := metric.Hash()
if !exists {
insertedSigs = map[uint64]struct{}{}
matchedSigs[sig] = insertedSigs
} else if _, duplicate := insertedSigs[insertSig]; duplicate {
ev.errorf("multiple matches for labels: grouping labels must ensure unique matches")
}
insertedSigs[insertSig] = struct{}{}
}
enh.out = append(enh.out, Sample{
Metric: metric,
Point: Point{V: value},
})
}
return enh.out
}
// signatureFunc returns a function that calculates the signature for a metric
// ignoring the provided labels. If on, then the given labels are only used instead.
func signatureFunc(on bool, names ...string) func(labels.Labels) uint64 {
// TODO(fabxc): ensure names are sorted and then use that and sortedness
// of labels by names to speed up the operations below.
// Alternatively, inline the hashing and don't build new label sets.
if on {
return func(lset labels.Labels) uint64 { return lset.HashForLabels(names...) }
}
return func(lset labels.Labels) uint64 { return lset.HashWithoutLabels(names...) }
}
// resultMetric returns the metric for the given sample(s) based on the Vector
// binary operation and the matching options.
func resultMetric(lhs, rhs labels.Labels, op ItemType, matching *VectorMatching, enh *EvalNodeHelper) labels.Labels {
if enh.resultMetric == nil {
enh.resultMetric = make(map[uint64]labels.Labels, len(enh.out))
}
// op and matching are always the same for a given node, so
// there's no need to include them in the hash key.
// If the lhs and rhs are the same then the xor would be 0,
// so add in one side to protect against that.
lh := lhs.Hash()
h := (lh ^ rhs.Hash()) + lh
if ret, ok := enh.resultMetric[h]; ok {
return ret
}
lb := labels.NewBuilder(lhs)
if shouldDropMetricName(op) {
lb.Del(labels.MetricName)
}
if matching.Card == CardOneToOne {
if matching.On {
Outer:
for _, l := range lhs {
for _, n := range matching.MatchingLabels {
if l.Name == n {
continue Outer
}
}
lb.Del(l.Name)
}
} else {
lb.Del(matching.MatchingLabels...)
}
}
for _, ln := range matching.Include {
// Included labels from the `group_x` modifier are taken from the "one"-side.
if v := rhs.Get(ln); v != "" {
lb.Set(ln, v)
} else {
lb.Del(ln)
}
}
ret := lb.Labels()
enh.resultMetric[h] = ret
return ret
}
// VectorscalarBinop evaluates a binary operation between a Vector and a Scalar.
func (ev *evaluator) VectorscalarBinop(op ItemType, lhs Vector, rhs Scalar, swap, returnBool bool, enh *EvalNodeHelper) Vector {
for _, lhsSample := range lhs {
lv, rv := lhsSample.V, rhs.V
// lhs always contains the Vector. If the original position was different
// swap for calculating the value.
if swap {
lv, rv = rv, lv
}
value, keep := vectorElemBinop(op, lv, rv)
if returnBool {
if keep {
value = 1.0
} else {
value = 0.0
}
keep = true
}
if keep {
lhsSample.V = value
if shouldDropMetricName(op) || returnBool {
lhsSample.Metric = enh.dropMetricName(lhsSample.Metric)
}
enh.out = append(enh.out, lhsSample)
}
}
return enh.out
}
func dropMetricName(l labels.Labels) labels.Labels {
return labels.NewBuilder(l).Del(labels.MetricName).Labels()
}
// scalarBinop evaluates a binary operation between two Scalars.
func scalarBinop(op ItemType, lhs, rhs float64) float64 {
switch op {
case itemADD:
return lhs + rhs
case itemSUB:
return lhs - rhs
case itemMUL:
return lhs * rhs
case itemDIV:
return lhs / rhs
case itemPOW:
return math.Pow(lhs, rhs)
case itemMOD:
return math.Mod(lhs, rhs)
case itemEQL:
return btos(lhs == rhs)
case itemNEQ:
return btos(lhs != rhs)
case itemGTR:
return btos(lhs > rhs)
case itemLSS:
return btos(lhs < rhs)
case itemGTE:
return btos(lhs >= rhs)
case itemLTE:
return btos(lhs <= rhs)
}
panic(fmt.Errorf("operator %q not allowed for Scalar operations", op))
}
// vectorElemBinop evaluates a binary operation between two Vector elements.
func vectorElemBinop(op ItemType, lhs, rhs float64) (float64, bool) {
switch op {
case itemADD:
return lhs + rhs, true
case itemSUB:
return lhs - rhs, true
case itemMUL:
return lhs * rhs, true
case itemDIV:
return lhs / rhs, true
case itemPOW:
return math.Pow(lhs, rhs), true
case itemMOD:
return math.Mod(lhs, rhs), true
case itemEQL:
return lhs, lhs == rhs
case itemNEQ:
return lhs, lhs != rhs
case itemGTR:
return lhs, lhs > rhs
case itemLSS:
return lhs, lhs < rhs
case itemGTE:
return lhs, lhs >= rhs
case itemLTE:
return lhs, lhs <= rhs
}
panic(fmt.Errorf("operator %q not allowed for operations between Vectors", op))
}
// intersection returns the metric of common label/value pairs of two input metrics.
func intersection(ls1, ls2 labels.Labels) labels.Labels {
res := make(labels.Labels, 0, 5)
for _, l1 := range ls1 {
for _, l2 := range ls2 {
if l1.Name == l2.Name && l1.Value == l2.Value {
res = append(res, l1)
continue
}
}
}
return res
}
type groupedAggregation struct {
labels labels.Labels
value float64
mean float64
groupCount int
heap vectorByValueHeap
reverseHeap vectorByReverseValueHeap
}
// aggregation evaluates an aggregation operation on a Vector.
func (ev *evaluator) aggregation(op ItemType, grouping []string, without bool, param interface{}, vec Vector, enh *EvalNodeHelper) Vector {
result := map[uint64]*groupedAggregation{}
var k int64
if op == itemTopK || op == itemBottomK {
f := param.(float64)
if !convertibleToInt64(f) {
ev.errorf("Scalar value %v overflows int64", f)
}
k = int64(f)
if k < 1 {
return Vector{}
}
}
var q float64
if op == itemQuantile {
q = param.(float64)
}
var valueLabel string
if op == itemCountValues {
valueLabel = param.(string)
if !model.LabelName(valueLabel).IsValid() {
ev.errorf("invalid label name %q", valueLabel)
}
if !without {
grouping = append(grouping, valueLabel)
}
}
for _, s := range vec {
metric := s.Metric
if op == itemCountValues {
lb := labels.NewBuilder(metric)
lb.Set(valueLabel, strconv.FormatFloat(s.V, 'f', -1, 64))
metric = lb.Labels()
}
var (
groupingKey uint64
)
if without {
groupingKey = metric.HashWithoutLabels(grouping...)
} else {
groupingKey = metric.HashForLabels(grouping...)
}
group, ok := result[groupingKey]
// Add a new group if it doesn't exist.
if !ok {
var m labels.Labels
if without {
lb := labels.NewBuilder(metric)
lb.Del(grouping...)
lb.Del(labels.MetricName)
m = lb.Labels()
} else {
m = make(labels.Labels, 0, len(grouping))
for _, l := range metric {
for _, n := range grouping {
if l.Name == n {
m = append(m, l)
break
}
}
}
sort.Sort(m)
}
result[groupingKey] = &groupedAggregation{
labels: m,
value: s.V,
mean: s.V,
groupCount: 1,
}
inputVecLen := int64(len(vec))
resultSize := k
if k > inputVecLen {
resultSize = inputVecLen
}
if op == itemStdvar || op == itemStddev {
result[groupingKey].value = 0.0
} else if op == itemTopK || op == itemQuantile {
result[groupingKey].heap = make(vectorByValueHeap, 0, resultSize)
heap.Push(&result[groupingKey].heap, &Sample{
Point: Point{V: s.V},
Metric: s.Metric,
})
} else if op == itemBottomK {
result[groupingKey].reverseHeap = make(vectorByReverseValueHeap, 0, resultSize)
heap.Push(&result[groupingKey].reverseHeap, &Sample{
Point: Point{V: s.V},
Metric: s.Metric,
})
}
continue
}
switch op {
case itemSum:
group.value += s.V
case itemAvg:
group.groupCount++
group.mean += (s.V - group.mean) / float64(group.groupCount)
case itemMax:
if group.value < s.V || math.IsNaN(group.value) {
group.value = s.V
}
case itemMin:
if group.value > s.V || math.IsNaN(group.value) {
group.value = s.V
}
case itemCount, itemCountValues:
group.groupCount++
case itemStdvar, itemStddev:
group.groupCount++
delta := s.V - group.mean
group.mean += delta / float64(group.groupCount)
group.value += delta * (s.V - group.mean)
case itemTopK:
if int64(len(group.heap)) < k || group.heap[0].V < s.V || math.IsNaN(group.heap[0].V) {
if int64(len(group.heap)) == k {
heap.Pop(&group.heap)
}
heap.Push(&group.heap, &Sample{
Point: Point{V: s.V},
Metric: s.Metric,
})
}
case itemBottomK:
if int64(len(group.reverseHeap)) < k || group.reverseHeap[0].V > s.V || math.IsNaN(group.reverseHeap[0].V) {
if int64(len(group.reverseHeap)) == k {
heap.Pop(&group.reverseHeap)
}
heap.Push(&group.reverseHeap, &Sample{
Point: Point{V: s.V},
Metric: s.Metric,
})
}
case itemQuantile:
group.heap = append(group.heap, s)
default:
panic(fmt.Errorf("expected aggregation operator but got %q", op))
}
}
// Construct the result Vector from the aggregated groups.
for _, aggr := range result {
switch op {
case itemAvg:
aggr.value = aggr.mean
case itemCount, itemCountValues:
aggr.value = float64(aggr.groupCount)
case itemStdvar:
aggr.value = aggr.value / float64(aggr.groupCount)
case itemStddev:
aggr.value = math.Sqrt(aggr.value / float64(aggr.groupCount))
case itemTopK:
// The heap keeps the lowest value on top, so reverse it.
sort.Sort(sort.Reverse(aggr.heap))
for _, v := range aggr.heap {
enh.out = append(enh.out, Sample{
Metric: v.Metric,
Point: Point{V: v.V},
})
}
continue // Bypass default append.
case itemBottomK:
// The heap keeps the lowest value on top, so reverse it.
sort.Sort(sort.Reverse(aggr.reverseHeap))
for _, v := range aggr.reverseHeap {
enh.out = append(enh.out, Sample{
Metric: v.Metric,
Point: Point{V: v.V},
})
}
continue // Bypass default append.
case itemQuantile:
aggr.value = quantile(q, aggr.heap)
default:
// For other aggregations, we already have the right value.
}
enh.out = append(enh.out, Sample{
Metric: aggr.labels,
Point: Point{V: aggr.value},
})
}
return enh.out
}
// btos returns 1 if b is true, 0 otherwise.
func btos(b bool) float64 {
if b {
return 1
}
return 0
}
// shouldDropMetricName returns whether the metric name should be dropped in the
// result of the op operation.
func shouldDropMetricName(op ItemType) bool {
switch op {
case itemADD, itemSUB, itemDIV, itemMUL, itemMOD:
return true
default:
return false
}
}
// LookbackDelta determines the time since the last sample after which a time
// series is considered stale.
var LookbackDelta = 5 * time.Minute
// documentedType returns the internal type to the equivalent
// user facing terminology as defined in the documentation.
func documentedType(t ValueType) string {
switch t {
case "vector":
return "instant vector"
case "matrix":
return "range vector"
default:
return string(t)
}
}