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• 版本回滚要存什么？只存最终产物够不够？What must a version record hold for rollback? Are the final artifacts enough?

  国内高频海外高频进阶#versioning#rollback#data-modeling

  分析过程 · 先想清楚再作答

  1. 题眼在「够不够」三个字，它在提示答案是否定的。先把问题重述成一句判断：**版本不是备份**，这句话说出来这题就答对了一半。
  2. 两者的语义不一样。备份是「出事了拿回来」，只需要保留最近一份好状态；版本是「两个都在」，要能并排对比、来回切换，最终选哪个由人定。审核场景要的是后者。
  3. 所以每个版本要存三类东西：产物本身（按版本分目录，一个文件都不删）、产生它的输入（那一版的台词与画面描述，否则三天后没人说得清两版差在哪）、以及这一版重跑了哪些节点与原因。
  4. 当前版本要设计成一个指针，不是一份拷贝。回滚就是把指针挪回去，不搬文件，因此是瞬时且可逆的；这也让「再切回新版本」变成理所当然的操作。
  5. 有一个连带影响必须提到，提了就说明你真做过：**回滚一镜会改变整集的时间轴**。新版配音比旧版长一秒，切回去之后后面所有镜头的起止时间都要重排。所以回滚之后要重算一次时间轴，好在这是纯本地计算，很便宜。
  6. 可预期的追问是「版本存多久」。按产物体积和业务价值定：小文本无限存，视频这种大件设一个保留期，过期只留元数据和输入，需要时可以按同样的输入重跑出来。

  How to reason about it · think before answering

  1. The hinge is are they enough, which signals the answer is no. Restate it as a claim: a version is not a backup. Saying that sentence gets you half the credit.
  2. The semantics differ. A backup means restore after an incident and only needs the latest good state. A version means both exist, side by side, switchable, with a human choosing. Review workflows need the latter.
  3. So each version stores three things: the artifacts themselves, kept in per-version directories with nothing deleted; the inputs that produced them, the line and the visual description, or nobody can explain the difference three days later; and which nodes reran plus why.
  4. The current version should be a pointer, not a copy. Rollback moves the pointer without touching files, which makes it instant and reversible, and makes switching forward again equally natural.
  5. Mention the knock-on effect, because it shows you have actually shipped this: rolling back one shot changes the whole episode timeline. If the new take of the voice is a second longer, every later shot shifts, so rollback must recompute the timeline. That part is cheap local computation.
  6. Expected follow-up: how long to keep versions. Scale it by artifact size and business value: keep small text forever, put a retention window on video, and after expiry keep only metadata and inputs so the artifact can be regenerated on demand.

  答题要点

  • 版本不是备份：备份只要最近一份好状态，版本要求新旧同时存在、能并排对比。
  • 每版要存三类：产物（按版本分目录、不删）、产生它的输入、重跑的节点与原因。
  • 当前版本是指针不是拷贝，回滚只挪指针，瞬时且可逆。
  • 回滚一镜会改变整集时间轴，回滚后要重算一次——这是纯本地计算，很便宜。
  • 保留策略按体积分级：文本长期留，大视频设保留期，过期只留元数据与输入以便按需重跑。

  Key points

  • A version is not a backup: backups keep the latest good state, versions keep old and new side by side.
  • Store three things per version: artifacts in per-version directories, the inputs that produced them, and which nodes reran and why.
  • Make the current version a pointer, not a copy, so rollback is instant and reversible.
  • Rolling back one shot shifts the episode timeline, so recompute it after rollback; it is cheap local work.
  • Set retention by size: keep text forever, expire large video and retain metadata plus inputs for regeneration.