Function `ParseKeyValue` has performance Bottleneck: Inefficient String Concatenation

[zhaojinxin409]

Component(s)

No response

Is your feature request related to a problem? Please describe.

The SplitString function has a significant performance bottleneck caused by inefficient string concatenation when processing long input strings. This leads to excessive memory allocations and high GC pressure, resulting in degraded performance (especially with strings longer than 1KB).

opentelemetry-collector-contrib/internal/coreinternal/parseutils/parser.go

Line 51 in 65171d9

current += string(input[i])

Test Case:

processors:
  transform/standard:
    error_mode: silent
    log_statements:
      - context: log
        statements:
          - set(attributes["log.type"], "test")
          - merge_maps(cache, ParseKeyValue(body), "upsert")

service:
  pipelines:
    logs/main:
      receivers: [filelog/log_file]
      processors: [transform/standard]
      exporters: [debug]

This is the cpu profile of otel collector

Describe the solution you'd like

use strings.Builder instead

Describe alternatives you've considered

No response

Additional context

Use strings.Builder

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[github-actions]

Pinging code owners for processor/transform: @TylerHelmuth @evan-bradley @edmocosta @bogdandrutu. See Adding Labels via Comments if you do not have permissions to add labels yourself. For example, comment '/label priority:p2 -needs-triage' to set the priority and remove the needs-triage label.

[github-actions]

Pinging code owners for pkg/ottl: @TylerHelmuth @evan-bradley @edmocosta @bogdandrutu. See Adding Labels via Comments if you do not have permissions to add labels yourself. For example, comment '/label priority:p2 -needs-triage' to set the priority and remove the needs-triage label.

[zhaojinxin409]

I can try to fix it if needed

[edmocosta]

Hi @zhaojinxin409, thank you opening this issue! It sounds like a fair request, and I think it would be simple to optimize it as suggested. Please feel free to give it a try if you want to. It would be nice to have some benchmarks (before vs after) to double check if the changes were effective. Please let me know if you need any help! :)