Guide to speed up remote R2 publish: raise concurrency now; S3 API + delta upload next.

Date: 2026-08-13 08:19 Summary: Guide to speed up remote R2 publish: raise concurrency now; S3 API + delta upload next.

[question] 如何优化R2的发布速度

[try to solve] The bottleneck is spawning wrangler CLI once per file, not gzip size. Speed up from low to high effort:

Current state

npm run upload:r2 runs ~1510 .html.gz files each via spawn npx wrangler r2 object put
Default R2_UPLOAD_CONCURRENCY=6
Wall clock is dominated by CLI cold start × count, not the ~24MB transfer
upload:r2:local writes via binding, so local is fast and remote is slow

Raise concurrency (simplest)
```
R2_UPLOAD_CONCURRENCY=20 npm run upload:r2
```
Empirically 12–24 is often faster than 6; higher may hit API limits or local CPU — tune a few times.
Skip the bucket when HTML did not change
```
npm run deploy:skip-upload
```
Use when only Worker/Assets changed.
Do not treat every local wrangler deploy as required Default path is upload → git push → CF pulls the repo; do not double-count Worker deploy and R2 fill as one slow path.

Direction	Effect	Approach
S3-compatible PutObject	Often “minutes–10+ min” → “tens of seconds”	`@aws-sdk/client-s3` + R2 endpoint; in-process concurrent `PutObject`; stop spawning wrangler. Use R2 S3 credentials (Object R/W), separate from wrangler Admin token
Delta only	Near seconds when one tool changes	Local build already has whole-bucket `contentHash`; extend meta with per-file sha256, compare last `.cache/pages-build.json` or R2 meta, put only changes + rewrite `_meta/pages-build.json`
Batch/pipeline	Stabilizes	CI: `build:site` → S3 upload → `verify:r2`; local push only; or local delta + CI full fallback

Priority: S3 direct upload (drop CLI) first → then delta. Concurrency tuning alone is a stopgap.

Further gzip compression: already .html.gz; size is not the main cost
Multipart: objects are small; multipart does not help
Expecting Cloudflare Git deploy to fill R2: remote default does not run upload:r2

Minimal script change: remote path in upload-r2-pages.mjs → S3 PutObject + optional --changed-only.

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