Questions tagged [uuid]

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High-cardinality UUID: how/where to store? [closed]

I have lots of devices, each identified by a unique UUID. For each device, I have one or more timeseries data (potentially up to millions of entries). What's the best way to store these entries? ...
persson's user avatar
  • 197
2 votes
3 answers
1k views

Should you manually generate UUIDs / GUIDs by modifying an existing UUID / GUID?

As an example imagine I generate a UUID/GUID for an ID in a json file. { "25d01302-2558-4c44-bf9d-385b1cc51377": ["somevalues"] } is it ok or generally frowned upon to do ...
RyanCosans's user avatar
1 vote
3 answers
1k views

Better than ongoing integer and uuid as primary key

I read a lot about using ongoing numbers vs UUIDs as the primary key and had an idea how it might be possible to combine both and profit from their advantages, without their disadvantages. The table ...
Mointy's user avatar
  • 119
1 vote
4 answers
1k views

Is using multiple UUIDs decrease chance of collisions exponentially?

For example if you have a single UUID with a collision probability of x, if you concatenate 2 UUIDs, does the collision probability become x^2? val0 = generate_uuid() val1 = generate_uuid() final_val ...
Joan Venge's user avatar
  • 1,960
-3 votes
2 answers
11k views

What is the minimum length for a UUID?

From general observation I've come across the standard to be 36. I was looking to incorporate a uuid in my urls but didn't want it that long. Is there a minimum where I can still keep the uuid unique?
Carl Edwards's user avatar
3 votes
2 answers
3k views

Generate UUID in Application or Database level?

I created a new application and I am thinking where is the best place to generate a UUID. Generate a UUID in application level and persist it Generate a UUID in Database level I have a feeling that ...
pik4's user avatar
  • 375
2 votes
1 answer
585 views

MySQL UUID storage/presentation

I'm looking at the way UUIDs are stored in MySQL. MySQL 8 still doesn't have a UUID data type, and it still doesn't have custom types, so there are two options - store it as a string or as a binary. ...
Oleg Mikheev's user avatar
0 votes
2 answers
385 views

Questioning the impact of UUIDs

When I first played with a NoSQL database I become aware of the impact of UUIDs in a distributed system. MongoDB defaults to ObjectIDs, but I've always questioned in which cases UUID (RFC4122) would ...
SystematicFrank's user avatar
2 votes
1 answer
2k views

How do I create Uuids in DDD Entities/Aggregates

As I am learning DDD to help build an app idea the proper way ;) I have come across a confusing aspect that I am trying to find a solution for. I understand the need for Uuids in an app the size of ...
designermonkey's user avatar
-2 votes
1 answer
618 views

Repository UUID equivalent

I am converting an old Subversion repository to Git. Here is an example: $ svn info http://alfa.com/bravo/charlie Path: charlie URL: http://alfa.com/bravo/charlie Relative URL: ^/charlie Repository ...
Zombo's user avatar
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4 votes
3 answers
7k views

UUID vs Integer

For a database. Should I use an UUID or an integer for the primary key? I will never exceed 2^32 in amount of rows, so an integer should be more than plenty. I would prefer to use an integer, as I ...
KaareZ's user avatar
  • 151
7 votes
1 answer
5k views

Uniformly distributing GUIDS to bucket of size N [closed]

How can uniformly and deterministically distribute set of GUIDS to N buckets. N can be as small as 2. Need to make sure the same GUID is always mapped to the same bucket. Can't use any additionally ...
FaisalMansoor's user avatar
3 votes
2 answers
2k views

Accepting the UUID collision risk based on number of clients

After reading some questions about the probability of UUID collisions it seems like collisions although unlikely, are still possible and a conflict solution is still needed. Therefore I am wondering ...
SystematicFrank's user avatar
2 votes
2 answers
2k views

Is it okay if we use an arbitrary string as UUID?

I found the tutorial of client (android) and server (pc) bluetooth tutorial from here. But my question is about the UUID. Is that okay if we define it randomly without the proper format? Because I ...
gumuruh's user avatar
  • 123
50 votes
3 answers
14k views

Strategy for generating unique and secure identifiers for use in a "sometimes offline" web app

I have a web based project that allows users to work both online and offline and I'm looking for a way to generate unique ids for records on the client side. I'd like an approach that works while a ...
herbrandson's user avatar
0 votes
2 answers
1k views

How deterministic are SessionIDs from SHA'd GUIDs?

Assume I'm using the following code to generate pseudo-random sessionID's: sessionID = SHA-512(GENERATE-GUID()) The GUIDs are pretty deterministic, i.e. I see lots of GUIDs with a lot of the same ...
Davio's user avatar
  • 101
0 votes
1 answer
453 views

How unique should a UUID identified object be?

I am working on a fairly large open source project (Drupal) and the next major version will begin to use UUIDs for a lot of things, including configuration objects. If we put UUIDs into the ...
chx's user avatar
  • 373
18 votes
2 answers
10k views

Why are UUID / GUID's in the format they are?

Globally Unique Identifiers (GUID) are a grouped string with a specific format which I assume has a security reason. A GUID is most commonly written in text as a sequence of hexadecimal digits ...
Xeoncross's user avatar
  • 1,213
26 votes
7 answers
15k views

How to generate "language-safe" UUIDs?

I always wanted to use randomly generated strings for my resources' IDs, so I could have shorter URLs like this: /user/4jz0k1 But I never did, because I was worried about the random string generation ...
HappyDeveloper's user avatar
10 votes
8 answers
2k views

A good schema to represent integer numbers from 0 to infinity, assuming you have infinite linear binary storage?

I would like a schema to represent integer numbers starting with 0, without any limit (assuming access to infinite linear storage). Here's a schema that can represent numbers from 0 to 255: Use the ...
Dmitri Shuralyov's user avatar
33 votes
6 answers
140k views

UUID collisions [closed]

Has anybody done any real research on the probability of UUID collisions, especially with version 4 (random) UUIDs, given that the random number generators we use aren't truly random and that we might ...
Paul Tomblin's user avatar
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