perf: parallelize suspension handler for high-concurrency

[pranaygp]

The current implementation of suspension handler processes the invocation queue sequentially which is really slow. Now we process is in parallel:

• Process hooks first, then steps and waits in parallel to prevent race conditions
• Refactor runtime.ts into modular files: suspension-handler.ts, step-handler.ts, helpers.ts
• nit: Add otel attributes for hooks created (workflow.hooks.created) and waits created (workflow.waits.created)
• nit: Update suspension status from pending_steps to workflow_suspended

[changeset-bot]

🦋 Changeset detected

Latest commit: 886548c

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 12 packages

Name	Type
@workflow/core	Patch
@workflow/builders	Patch
@workflow/cli	Patch
@workflow/next	Patch
@workflow/nitro	Patch
@workflow/web-shared	Patch
workflow	Patch
@workflow/astro	Patch
@workflow/sveltekit	Patch
@workflow/world-testing	Patch
@workflow/nuxt	Patch
@workflow/ai	Patch

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Project	Deployment	Review	Updated (UTC)
example-nextjs-workflow-turbopack	Ready	Preview, Comment	Dec 18, 2025 2:28am
example-nextjs-workflow-webpack	Ready	Preview, Comment	Dec 18, 2025 2:28am
example-workflow	Ready	Preview, Comment	Dec 18, 2025 2:28am
workbench-astro-workflow	Ready	Preview, Comment	Dec 18, 2025 2:28am
workbench-express-workflow	Ready	Preview, Comment	Dec 18, 2025 2:28am
workbench-fastify-workflow	Ready	Preview, Comment	Dec 18, 2025 2:28am
workbench-hono-workflow	Ready	Preview, Comment	Dec 18, 2025 2:28am
workbench-nitro-workflow	Ready	Preview, Comment	Dec 18, 2025 2:28am
workbench-nuxt-workflow	Ready	Preview, Comment	Dec 18, 2025 2:28am
workbench-sveltekit-workflow	Ready	Preview, Comment	Dec 18, 2025 2:28am
workbench-vite-workflow	Ready	Preview, Comment	Dec 18, 2025 2:28am
workflow-docs	Ready	Preview, Comment	Dec 18, 2025 2:28am

[github-actions]

🧪 E2E Test Results

❌ Some tests failed

Summary

	Passed	Failed	Skipped	Total
✅ ▲ Vercel Production	286	0	11	297
✅ 💻 Local Development	262	0	8	270
✅ 📦 Local Production	262	0	8	270
✅ 🐘 Local Postgres	262	0	8	270
✅ 🪟 Windows	27	0	0	27
❌ 🌍 Community Worlds	109	11	0	120
Total	1208	11	35	1254

❌ Failed Tests

🌍 Community Worlds (11 failed)

mongodb (1 failed):

• webhookWorkflow

redis (1 failed):

• webhookWorkflow

starter (8 failed):

• addTenWorkflow
• addTenWorkflow
• retryAttemptCounterWorkflow
• crossFileErrorWorkflow - stack traces work across imported modules
• hookCleanupTestWorkflow - hook token reuse after workflow completion
• stepFunctionPassingWorkflow - step function references can be passed as arguments (without closure vars)
• stepFunctionWithClosureWorkflow - step function with closure variables passed as argument
• spawnWorkflowFromStepWorkflow - spawning a child workflow using start() inside a step

turso (1 failed):

• webhookWorkflow

Details by Category

✅ ▲ Vercel Production

App	Passed	Failed	Skipped
✅ astro	26	0	1
✅ example	26	0	1
✅ express	26	0	1
✅ fastify	26	0	1
✅ hono	26	0	1
✅ nextjs-turbopack	26	0	1
✅ nextjs-webpack	26	0	1
✅ nitro	26	0	1
✅ nuxt	26	0	1
✅ sveltekit	26	0	1
✅ vite	26	0	1

✅ 💻 Local Development

App	Passed	Failed	Skipped
✅ astro-stable	26	0	1
✅ express-stable	26	0	1
✅ fastify-stable	26	0	1
✅ hono-stable	26	0	1
✅ nextjs-turbopack-stable	27	0	0
✅ nextjs-webpack-stable	27	0	0
✅ nitro-stable	26	0	1
✅ nuxt-stable	26	0	1
✅ sveltekit-stable	26	0	1
✅ vite-stable	26	0	1

✅ 📦 Local Production

App	Passed	Failed	Skipped
✅ astro-stable	26	0	1
✅ express-stable	26	0	1
✅ fastify-stable	26	0	1
✅ hono-stable	26	0	1
✅ nextjs-turbopack-stable	27	0	0
✅ nextjs-webpack-stable	27	0	0
✅ nitro-stable	26	0	1
✅ nuxt-stable	26	0	1
✅ sveltekit-stable	26	0	1
✅ vite-stable	26	0	1

✅ 🐘 Local Postgres

App	Passed	Failed	Skipped
✅ astro-stable	26	0	1
✅ express-stable	26	0	1
✅ fastify-stable	26	0	1
✅ hono-stable	26	0	1
✅ nextjs-turbopack-stable	27	0	0
✅ nextjs-webpack-stable	27	0	0
✅ nitro-stable	26	0	1
✅ nuxt-stable	26	0	1
✅ sveltekit-stable	26	0	1
✅ vite-stable	26	0	1

✅ 🪟 Windows

App	Passed	Failed	Skipped
✅ nextjs-turbopack	27	0	0

❌ 🌍 Community Worlds

App	Passed	Failed	Skipped
✅ mongodb-dev	3	0	0
❌ mongodb	26	1	0
✅ redis-dev	3	0	0
❌ redis	26	1	0
✅ starter-dev	3	0	0
❌ starter	19	8	0
✅ turso-dev	3	0	0
❌ turso	26	1	0

---

📋 View full workflow run

[pranaygp]

• perf: parallelize suspension handler for high-concurrency #544 : 2 dependent PRs (#620 , #621 ) 👈 (View in Graphite)
• perf: use Map for invocationsQueue (O(1) lookup/delete) #541
• Add stress test benchmarks for large concurrent step counts #539
• main

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