revert: Make Wait node fully durable by removing in-memory execution path

[shortstacked]

Summary

Reverts #27066 (f025a786e75ec962fcaca469c107324eea8548a3).

This restores the original Wait node behavior where waits shorter than 65 seconds run in-memory via setTimeout, and removes the DB-server-clock-anchored scheduling infrastructure introduced in the reverted PR.

What is restored:

• Wait node: the < 65s in-memory execution path
• WaitTracker: 60s poll interval with Date.now()-based timing
• ExecutionRepository: original getWaitingExecutions() without lookahead window

What is removed:

• ClockRepository and DbClockService (DB server clock syncing)
• n8n_db_clock_skew_ms Prometheus gauge
• 5s poll interval and 15s lookahead window

Review / Merge checklist

• I have seen this code, I have run this code, and I take responsibility for this code.
• PR title and summary are descriptive. (conventions)
• Docs updated or follow-up ticket created.
• Tests included.
• PR Labeled with Backport to Beta, Backport to Stable, or Backport to v1 (if the PR is an urgent fix that needs to be backported)

[codecov]

Codecov Report

❌ Patch coverage is 70.90909% with 16 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
packages/cli/src/wait-tracker.ts	76.19%	10 Missing ⚠️
...s/@n8n/db/src/repositories/execution.repository.ts	0.00%	6 Missing ⚠️

📢 Thoughts on this report? Let us know!

[github-actions]

Performance Comparison

Comparing current → latest master → 14-day baseline

docker-stats

Metric	Current	Latest Master	Baseline (avg)	vs Master	vs Baseline	Status
docker-image-size-n8n	1269.76 MB	1269.76 MB	1269.76 MB (σ 0.00)	+0.0%	+0.0%	—
docker-image-size-runners	393.00 MB	393.00 MB	391.78 MB (σ 10.35)	+0.0%	+0.3%	✅

Idle baseline with Instance AI module loaded

Metric	Current	Latest Master	Baseline (avg)	vs Master	vs Baseline	Status
instance-ai-heap-used-baseline	186.31 MB	186.36 MB	186.34 MB (σ 0.22)	-0.0%	-0.0%	✅
instance-ai-rss-baseline	383.03 MB	341.24 MB	368.15 MB (σ 24.08)	+12.2%	+4.0%	✅

Memory consumption baseline with starter plan resources

Metric	Current	Latest Master	Baseline (avg)	vs Master	vs Baseline	Status
memory-heap-used-baseline	114.32 MB	114.54 MB	114.07 MB (σ 0.54)	-0.2%	+0.2%	✅
memory-rss-baseline	284.32 MB	332.36 MB	289.54 MB (σ 44.00)	-14.5%	-1.8%	✅

How to read this table

• Current: This PR's value (or latest master if PR perf tests haven't run)
• Latest Master: Most recent nightly master measurement
• Baseline: Rolling 14-day average from master
• vs Master: PR impact (current vs latest master)
• vs Baseline: Drift from baseline (current vs rolling avg)
• Status: ✅ within 1σ | ⚠️ 1-2σ | 🔴 >2σ regression

[gml3ff]

Looks good to me, thanks for submitting this.

[n8n-assistant]

Successfully created backport PR for release-candidate/2.17.x:

• revert: Make Wait node fully durable by removing in-memory execution path (backport to release-candidate/2.17.x) #28574

[n8n-assistant]

Successfully created backport PR for release-candidate/2.16.x:

• revert: Make Wait node fully durable by removing in-memory execution path (backport to release-candidate/2.16.x) #28575

[n8n-assistant]

Got released with n8n@2.18.0