Worker prompts drop everything downstream of DistributedCollector /
UltimateSDUpscaleDistributed, so the master re-added a PreviewImage
(or PreviewAudio) to give ComfyUI an output node. That preview wrote
every result frame as a PNG into the worker's temp directory: for a
362-frame 1344x768 video, ~2 GB per run (RAM when temp is on tmpfs)
plus CPU time spent PNG-encoding frames nobody looks at.
- Add DistributedWorkerSink: an output node that discards its input.
It is is_dev_only, so it stays out of node search and menus.
- The master probes each worker with GET /object_info/DistributedWorkerSink
while preparing its prompt and uses the sink when it is registered.
Workers on older versions (or a failed probe) keep the PreviewImage /
PreviewAudio terminator, so mixed versions keep working.
Verified with a real master plus one updated and one old worker:
the updated worker ran EmptyImage -> Collector -> Sink and left its
temp directory empty; the old worker still received PreviewImage.
Claude-Session: https://claude.ai/code/session_0166t8T3CVaxZkJbP2RtSpo6
Co-authored-by: ymiyad <cab-13-might@icloud.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
