UUID v7

[Mike Kerner]

it's an interesting topic, because in one of the db communities i'm
involved with, they're actually going the other way, increasing entropy.

On Fri, Sep 1, 2023 at 1:56 PM Tom Glod via use-livecode <
use-livecode at lists.runrev.com> wrote:

> Hi Mike,
>
> Sometimes you just don't need uniqueness across all bits, and if you do,
> use v4.
> In my example, the ID is used for clipboard clips, but now I don't have to
> sort them based on their timestamp.
> Also this improves database performance as the btree is better organized.
> There are a few videos and lots of papers on the topic.
>
>
> On Fri, Sep 1, 2023 at 1:38 PM Mike Kerner via use-livecode <
> use-livecode at lists.runrev.com> wrote:
>
> > why would reducing randomness be desirable in an internet-facing app?
> isn't
> > the whole point to
> > * ensure uniqueness across the entire space
> > * make it nearly impossible to guess an ID?
> > i would think that once you make the id's sequential, you have eliminated
> > the ability to stop an authorized user from randomly marching through
> your
> > data.
> >
> > On Fri, Sep 1, 2023 at 1:21 PM Tom Glod via use-livecode <
> > use-livecode at lists.runrev.com> wrote:
> >
> > > Hi Folks,
> > >
> > > Sharing this because its useful, and also, more eyeballs on the code
> > makes
> > > sense.
> > > I implemented this with the help of chatGPT.
> > >
> > > This is a handler that can generate v7 UUIDs.
> > > v7 UUIDs work better in databases, because they are not so random,
> > > improving performance.
> > > And they are sequential.
> > > They also match the format of uuid v4
> > > Also the specs for v7 have not yet been finalized.
> > >
> > > Here it is:
> > >
> > > function CreateUUID pVersion
> > >    // This Handler returns a
> > >    if pVersion is not 7 then
> > >       //Return V4 Random UUID
> > >       return uuid("random")
> > >
> > >    else if pVersion = 7 then
> > >       // return V7 Random yet sequenced UUID
> > >
> > >       local tUnixTsMs, tVer, tRandA, tTVar, tRandB, tTheID
> > >       -- Get the current timestamp in milliseconds
> > >
> > >       put baseConvert(the milliseconds, 10, 16) into tUnixTsMs
> > >       put format("%012s", tUnixTsMs) into tUnixTsMs
> > >
> > >       // Set the version field to 0b0111 (7)
> > >       put "7" into tVer
> > >
> > >       // Generate 12 bits of pseudo-random data for RAND A
> > >       put random(4095) into tRandA -- 4095 is the maximum value for 12
> > bits
> > >       put baseConvert(tRandA, 10, 16) into tRandA
> > >       put format("%03s", tRandA) into tRandA
> > >
> > >       // Set the variant field to 0b10
> > >       put "8" into tTVar -- 0b10 in hexadecimal
> > >
> > >       // Generate 62 bits of pseudo-random data for RAND B
> > >       repeat 16 times
> > >          put baseConvert(random(15), 10, 16) after tRandB -- generate
> one
> > > hex digit at a time
> > >       end repeat
> > >
> > >       // Combine all the bits to form the UUID
> > >       put tUnixTsMs & tVer & tRandA & tTVar & tRandB into tTheID
> > >
> > >       // Insert dashes to form the UUID in 8-4-4-4-12 format
> > >       put char 1 to 8 of tTheID & "-" & char 9 to 12 of tTheID & "-" &
> > char
> > > 13 to 16 of tTheID & "-" & char 17 to 20 of tTheID & "-" & char 21 to
> 32
> > of
> > > tTheID into tTheID
> > >
> > >       return tTheID
> > >    end if
> > > end CreateUUID tVersion
> > >
> > > Cheers,
> > >
> > > Tom
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> >
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-- 
On the first day, God created the heavens and the Earth
On the second day, God created the oceans.
On the third day, God put the animals on hold for a few hours,
   and did a little diving.
And God said, "This is good."