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[ENHANCEMENT] PromQL: Add detail to tracing spans 

For aggregates, operators, calls, show what operation is performed.
Also add an event when series are expanded, typically time spent
accessing TSDB.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
This commit is contained in:
Bryan Boreham 2024-09-02 13:38:05 +01:00
parent 54989ce6fd
commit abb0502685
1 changed files with 8 additions and 0 deletions
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8
promql/engine.go
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@ -991,6 +991,8 @@ func checkAndExpandSeriesSet(ctx context.Context, expr parser.Expr) (annotations
if e.Series != nil { if e.Series != nil {
return nil, nil return nil, nil
} }
span := trace.SpanFromContext(ctx)
span.AddEvent("expand start", trace.WithAttributes(attribute.String("selector", e.String())))
series, ws, err := expandSeriesSet(ctx, e.UnexpandedSeriesSet) series, ws, err := expandSeriesSet(ctx, e.UnexpandedSeriesSet)
if e.SkipHistogramBuckets { if e.SkipHistogramBuckets {
for i := range series { for i := range series {
@ -998,6 +1000,7 @@ func checkAndExpandSeriesSet(ctx context.Context, expr parser.Expr) (annotations
} }
} }
e.Series = series e.Series = series
span.AddEvent("expand end", trace.WithAttributes(attribute.Int("num_series", len(series))))
return ws, err return ws, err
} }
return nil, nil return nil, nil
@ -1475,6 +1478,9 @@ func (ev *evaluator) eval(ctx context.Context, expr parser.Expr) (parser.Value,
// Create a new span to help investigate inner evaluation performances. // Create a new span to help investigate inner evaluation performances.
ctx, span := otel.Tracer("").Start(ctx, stats.InnerEvalTime.SpanOperation()+" eval "+reflect.TypeOf(expr).String()) ctx, span := otel.Tracer("").Start(ctx, stats.InnerEvalTime.SpanOperation()+" eval "+reflect.TypeOf(expr).String())
defer span.End() defer span.End()
if ss, ok := expr.(interface{ ShortString() string }); ok {
span.SetAttributes(attribute.String("operation", ss.ShortString()))
}
switch e := expr.(type) { switch e := expr.(type) {
case *parser.AggregateExpr: case *parser.AggregateExpr:
@ -1849,11 +1855,13 @@ func (ev *evaluator) eval(ctx context.Context, expr parser.Expr) (parser.Value,
} }
case *parser.NumberLiteral: case *parser.NumberLiteral:
span.SetAttributes(attribute.Float64("value", e.Val))
return ev.rangeEval(ctx, nil, func(v []parser.Value, _ [][]EvalSeriesHelper, enh *EvalNodeHelper) (Vector, annotations.Annotations) { return ev.rangeEval(ctx, nil, func(v []parser.Value, _ [][]EvalSeriesHelper, enh *EvalNodeHelper) (Vector, annotations.Annotations) {
return append(enh.Out, Sample{F: e.Val, Metric: labels.EmptyLabels()}), nil return append(enh.Out, Sample{F: e.Val, Metric: labels.EmptyLabels()}), nil
}) })
case *parser.StringLiteral: case *parser.StringLiteral:
span.SetAttributes(attribute.String("value", e.Val))
return String{V: e.Val, T: ev.startTimestamp}, nil return String{V: e.Val, T: ev.startTimestamp}, nil
case *parser.VectorSelector: case *parser.VectorSelector: