jaegertracing/jaeger · error

max spans count reached

Error message

max spans count reached

What it means

forThisEngine translates a regex-ish text pattern into an Elasticsearch wildcard/regexp query. Perl shorthand classes such as \d, \w, \s are rejected with tracestore.ErrFilterUnsupported because the engine reads them as literal characters rather than character classes, so honoring them would silently match the wrong text. The error tells the caller to write the class out explicitly (e.g. [0-9] instead of \d).

Source

Thrown at cmd/anonymizer/app/writer/writer.go:21

package writer

import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"os"
	"sync"

	"github.com/gogo/protobuf/jsonpb"
	"go.uber.org/zap"

	"github.com/jaegertracing/jaeger-idl/model/v1"
	"github.com/jaegertracing/jaeger/cmd/anonymizer/app/anonymizer"
)

var ErrMaxSpansCountReached = errors.New("max spans count reached")

// Config contains parameters to NewWriter.
type Config struct {
	MaxSpansCount  int                `yaml:"max_spans_count" name:"max_spans_count"`
	CapturedFile   string             `yaml:"captured_file" name:"captured_file"`
	AnonymizedFile string             `yaml:"anonymized_file" name:"anonymized_file"`
	MappingFile    string             `yaml:"mapping_file" name:"mapping_file"`
	AnonymizerOpts anonymizer.Options `yaml:"anonymizer" name:"anonymizer"`
}

// Writer is a span Writer that obfuscates the span and writes it to a JSON file.
type Writer struct {
	config         Config
	lock           sync.Mutex
	logger         *zap.Logger
	capturedFile   *os.File
	anonymizedFile *os.File
	anonymizer     *anonymizer.Anonymizer

View on GitHub (pinned to 806f444784)

Solutions

1. Replace the shorthand with an explicit character class: [0-9] for \d, [a-zA-Z0-9_] for \w, [ \t] for \s.
2. Catch the error with errors.Is(err, tracestore.ErrFilterUnsupported) and rewrite the pattern client-side before retrying.
3. Escape the backslash if a literal backslash-character match was actually intended.

Example fix

// before
service_name =~ "\d+"
// after
service_name =~ "[0-9]+"

var perlShorthandRe = regexp.MustCompile(`\\[dwsDWS]`)
func patternSafe(p string) bool { return !perlShorthandRe.MatchString(p) }

vm, err := forThisEngine(pattern)
if errors.Is(err, tracestore.ErrFilterUnsupported) {
    pattern = expandPerlShorthand(pattern) // \d -> [0-9], retry
}

When it happens

Trigger: Calling a trace search whose text comparison (attribute or field text match via attributeValueMatch or buildTextComparison) contains a pattern with Perl shorthand escapes like \d, \w, \s in it.

Common situations: Copy-pasting a PCRE/RE2 regex into a Jaeger query; writing attribute 'http.url' =~ "\d+" expecting digit matching; porting filters written for a regex-capable backend to the Elasticsearch backend.

Related errors

• empty configuration
• file must begin with '['
• at least one storage backend is required
• cannot assign unique span ID, too many spans in the trace
• invalid parameters

AI-assisted analysis of jaegertracing/jaeger@806f444784 (2026-09-01). Data as JSON: /api/errors/42343cf8da44544e. Report an issue: GitHub.