4 ms·

There's no need to explicitly version your first version of this though. Those first-version values are easy to identify: they don't contain versioning informa

by Groxx 4y ago

There's no need to explicitly version your first version of this though. Those first-version values are easy to identify: they don't contain versioning information :) E.g. say you have `5baa61e4c9b93f3f0682250b6cf8331b7ee68fd8`. What version is that? Well. It's exactly as long as a SHA1 hash. It doesn't start with "sha256:" or "md5:" or "h1:" or "rot13:". So it's SHA1. Easy and totally unambiguous. Versioning can almost always begin with version 2.

morelisp 4y ago
Me, sowing: "Each record begins with a 4 octet BE value indicating the record length." Me, reaping: "Each record begins with a single byte indicating the record format version. In version 0, this is followed by a 3 octet BE value indicating the record length."
- Groxx 4y ago
  if you're storing the raw binary rather than hex or base64: yeah. there are often no illegal values, so there's no way to safely extend it, unless you can differentiate on length. for those, you have to leave versioning room up-front. even 1 bit is enough, since a `1` can imply "following data describes the version", if a bit wastefully in the long run.
- nh23423fefe 4y ago
  sow then reap
  - morelisp 4y ago
    Well this fucking sucks. What the fuck.
    - cdelsolar 4y ago
      What are you guys even talking about
      - etc-hosts 4y ago
        https://twitter.com/screaminbutcalm/status/1105577845642878976 https://twitter.com/screaminbutcalm/status/11055778456428789...
    - nh23423fefe 4y ago
      i deserved it, i guess, lol
      - deleted 4y ago
        [deleted]
- kazinator 4y ago
  That's not applicable to Grox's example. The initial version uses only hexadecimal digits for the SHA256. If you had: "each record begins with an 8 character record length, in hexadecimal, giving 32 bits", you have no problems. The new version has a 'V' character in byte 0, which is rejected as invalid by the old implementation.
  - morelisp 4y ago
    Love too put another branch in the decoder I need to run a billion times.
    - guipsp 4y ago
      I beg you: please clone git, do the changes, and benchmark them. I bet you won't be able to obtain a statistically significant result from this single branch.
      - morelisp 4y ago
        It’s “almost always” though, not “in git for this one ID we already messed up”.
arccy 4y ago
versioning also allows you to change the inputs on the future to include/exclude more info inconsistencies in how data is presented (optional version number) is a pain to deal with in code

by Groxx 4y ago

morelisp 4y ago

Me, sowing: "Each record begins with a 4 octet BE value indicating the record length." Me, reaping: "Each record begins with a single byte indicating the record format version. In version 0, this is followed by a 3 octet BE value indicating the record length."

Groxx 4y ago
if you're storing the raw binary rather than hex or base64: yeah. there are often no illegal values, so there's no way to safely extend it, unless you can differentiate on length. for those, you have to leave versioning room up-front. even 1 bit is enough, since a `1` can imply "following data describes the version", if a bit wastefully in the long run.
nh23423fefe 4y ago
sow then reap
- morelisp 4y ago
  Well this fucking sucks. What the fuck.
  - cdelsolar 4y ago
    What are you guys even talking about
    - etc-hosts 4y ago
      https://twitter.com/screaminbutcalm/status/1105577845642878976 https://twitter.com/screaminbutcalm/status/11055778456428789...
  - nh23423fefe 4y ago
    i deserved it, i guess, lol
    - deleted 4y ago
      [deleted]
kazinator 4y ago
That's not applicable to Grox's example. The initial version uses only hexadecimal digits for the SHA256. If you had: "each record begins with an 8 character record length, in hexadecimal, giving 32 bits", you have no problems. The new version has a 'V' character in byte 0, which is rejected as invalid by the old implementation.
- morelisp 4y ago
  Love too put another branch in the decoder I need to run a billion times.
  - guipsp 4y ago
    I beg you: please clone git, do the changes, and benchmark them. I bet you won't be able to obtain a statistically significant result from this single branch.
    - morelisp 4y ago
      It’s “almost always” though, not “in git for this one ID we already messed up”.

arccy 4y ago

versioning also allows you to change the inputs on the future to include/exclude more info inconsistencies in how data is presented (optional version number) is a pain to deal with in code