Paginate Traces tab with step filter

[abidlabs]

Continuing the work that @edbeeching started in #540, this PR implements:

• Server-paginated Traces tab: get_traces gains step + limit/offset; new get_trace_steps returns per-step counts.
• Traces.svelte adds a step dropdown and 50/page prev/next; existing search, sort, and expandable rows are preserved.
• trackio.log() accepts list[Trace] so one step can carry a batch of rollouts.
• Example: examples/traces/large-trace-batch.py logs 200 steps × 40 traces (8000 total) for performance testing.

[gradio-pr-bot]

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•	Name	Status	URL
🦄	Changes	detected!	Details

[gradio-pr-bot]

🦄 change detected

This Pull Request includes changes to the following packages.

Package	Version
trackio	minor

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• Paginate Traces tab with step filter

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[HuggingFaceDocBuilderDev]

🪼 branch checks and previews

•	Name	Status	URL
	Spaces	ready!	Spaces preview

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Install Trackio from this PR (includes built frontend)

pip install "https://huggingface.co/buckets/trackio/trackio-wheels/resolve/e743a4b87070762366277953e5c202948bf1cdb6/trackio-0.25.1-py3-none-any.whl"

[HuggingFaceDocBuilderDev]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.

[Copilot]

Pull request overview

This PR extends Trackio’s trace viewer to handle large trace volumes more efficiently by adding server-side pagination and step-based filtering, plus support for logging batched traces at a single step.

Changes:

• Add step + limit/offset support to the traces backend API, and introduce a get_trace_steps endpoint for per-step counts.
• Update the Traces UI to include a step dropdown and 50-per-page pagination while preserving search/sort/expandable rows.
• Allow trackio.log() to accept list[Trace] values, and add an example script to generate large batched trace runs.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
trackio/sqlite_storage.py	Adds step filtering for get_traces and implements get_trace_steps aggregation.
trackio/server.py	Exposes step in get_traces and registers new get_trace_steps API.
trackio/run.py	Converts list[Trace] metric values into serializable dicts and queues media uploads.
trackio/frontend/src/pages/Traces.svelte	Adds step filter UI, server pagination wiring, and pagination controls.
trackio/frontend/src/lib/staticApi.js	Adds static-mode getTraceSteps and step filtering for traces.
trackio/frontend/src/lib/api.js	Adds getTraceSteps client API wrapper (static + server modes).
examples/traces/large-trace-batch.py	Adds a performance/stress test example generating large batched traces.
.changeset/young-views-do.md	Declares a minor release changeset for the feature.

Comments suppressed due to low confidence (3)

trackio/frontend/src/pages/Traces.svelte:273

• activeTotal multiplies the already-merged per-step count by selectedRuns.length, which overstates totals when multiple runs are selected (and inflates totalPages). Since loadSummary() sums counts across runs into availableSteps, the multiplier should be removed so totals/pagination reflect the real trace count.

  let activeTotal = $derived.by(() => {
    if (stepFilter === "all") return totalCount;
    const stepNum = Number(stepFilter);
    const entry = availableSteps.find((s) => s.step === stepNum);
    return entry ? entry.count * Math.max(1, selectedRuns.length) : 0;
  });

trackio/frontend/src/pages/Traces.svelte:167

• The summary refresh/reset logic only keys off selectedRuns (runsKey(selectedRuns)), so switching project while keeping the same run selection can leave availableSteps/totalCount stale and pagination state inconsistent. Include project in the key (or track lastProject) so loadSummary() runs and paging/filter state resets on project changes.

  $effect(() => {
    project;
    const key = runsKey(selectedRuns);
    if (key !== lastRunsKey) {
      lastRunsKey = key;
      page = 0;
      stepFilter = "all";
      loadSummary();
    }

trackio/frontend/src/pages/Traces.svelte:183

• Pagination (totalPages) is derived from totalCount/availableSteps, but those totals ignore the current search filter. With a non-empty search, the UI can show many pages and allow navigating to pages that will be empty even though there are no more matches. Consider returning a filtered total from the backend (e.g., add a count field/endpoint that takes search+step), or change the Next/total-pages logic to be driven by whether the current fetch returns a full page of results.

  $effect(() => {
    const trimmed = search.trim();
    if (trimmed !== lastSearch || sortBy !== lastSort || stepFilter !== lastStep) {
      if (lastSearch !== "" || trimmed !== "" || sortBy !== lastSort || stepFilter !== lastStep) {
        page = 0;
      }
      lastSearch = trimmed;
      lastSort = sortBy;
      lastStep = stepFilter;
    }

    const timeout = setTimeout(() => {
      loadTraces(trimmed, sortBy, stepFilter, page);
    }, 150);

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[abidlabs]

Thanks @Saba9!