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Identify All the Things With UUIDs! (Dutch PHP 2016)

Identify All the Things With UUIDs! (Dutch PHP 2016)

Universally unique identifiers (UUIDs) are a fun and exciting way to identify things. We can issue UUIDs forever and never run out; they're practically unique! Join this whirlwind adventure in search of the perfect identifier to find out why UUIDs might be good for your projects. Along the way, you'll learn what is a UUID, the various types of UUIDs, pros and cons of using UUIDs, and how to use the ramsey/uuid library. Advanced and little-known features of ramsey/uuid will be covered.


Ben Ramsey

June 24, 2016


  1. Identify All the Things With UUIDs Ben Ramsey Dutch PHP

    Conference 24 June 2016
  2. None
  3. universally unique identifier U U ID

  4. universally unique There are 1632 possible UUIDs “only after generating

    1 billion UUIDs every second for the next 100 years, the probability of creating just one duplicate would be about 50%” — Wikipedia, UUID
  5. 379dae82-5a2b-4c4b-8193-b8e7749a3495 Unsigned 128-bit integer

  6. 73 926 269 841 798 498 179 266 328 839

    241 479 317 Unsigned 128-bit integer
  7. b"7Ø«éZ+LKüô©þtÜ4ò" Unsigned 128-bit integer

  8. None
  9. HI, I’M BEN. I’m a web craftsman, author, and speaker.

    I build a platform for professional photographers at ShootProof. I enjoy APIs, open source software, organizing user groups, good beer, and spending time with my family. Nashville, TN is my home. ▸ Zend PHP Certification Study Guide ▸ Nashville PHP & Atlanta PHP user groups ▸ array_column() ▸ league/oauth2-client ▸ ramsey/uuid
  10. None
  11. ramsey/uuid

  12. composer require ramsey/uuid

  13. use Ramsey\Uuid\Uuid;

  14. RFC 4122 Defines a specific variant of UUID with five

  15. Anatomy of a UUID

  16. 379dae82-5a2b-4c4b-8193-b8e7749a3495

  17. 379dae82-5a2b-4c4b-8193-b8e7749a3495 time low

  18. 379dae82-5a2b-4c4b-8193-b8e7749a3495 time mid

  19. 379dae82-5a2b-4c4b-8193-b8e7749a3495 time high & version

  20. 379dae82-5a2b-4c4b-8193-b8e7749a3495 time high & version UUID version

  21. 379dae82-5a2b-4c4b-8193-b8e7749a3495 clock sequence high & reserved

  22. 379dae82-5a2b-4c4b-8193-b8e7749a3495 clock sequence high & reserved UUID variant

  23. 379dae82-5a2b-4c4b-8193-b8e7749a3495 clock sequence low

  24. 379dae82-5a2b-4c4b-8193-b8e7749a3495 node

  25. Version 1: Time Based

  26. $uuid = Uuid::uuid1(); echo $uuid->toString();

  27. for ($i = 0; $i < 5; $i++) { echo

    Uuid::uuid1()->toString(); echo "\n"; }
  28. 68845efc-1303-11e6-8d40-3c15c2cafa76 68846d0c-1303-11e6-8088-3c15c2cafa76 68847216-1303-11e6-830b-3c15c2cafa76 68847590-1303-11e6-892a-3c15c2cafa76 68847806-1303-11e6-913b-3c15c2cafa76

  29. Version 4: Random

  30. for ($i = 0; $i < 5; $i++) { echo

    Uuid::uuid4()->toString(); echo "\n"; }
  31. 28b7883f-3df0-4e8a-9994-57b28f01fab2 dd78278c-03d7-4ca4-8411-06380c4cfd57 ae8de9f1-6ffc-454e-8522-b2c260e4c66b a5e9ac6b-0680-4fb7-a019-f305c7d2d5da 09fd4b15-2b2d-49be-af51-30899169ff99

  32. Name Based: Version 3 & 5

  33. $uuid = Uuid::uuid3( Uuid::NAMESPACE_DNS, '' );

  34. 2f75e334-aa61-3af8-b570-49dd823d7248

  35. $uuid = Uuid::uuid5( Uuid::NAMESPACE_DNS, '' );

  36. f2a7c7f9-358c-51b7-ab30-cc456c5b2256

  37. $dpcNS = Uuid::uuid5( Uuid::NAMESPACE_DNS, '' ); define( 'NAMESPACE_DPC', $dpcNS->toString() );

    $pageId = Uuid::uuid5( NAMESPACE_DPC, '/about-dpc' );
  38. Version 2?

  39. Version 2: DCE Security

  40. Advanced

  41. Database Considerations • Some databases have UUID as native type

    • MySQL does not • InnoDB uses PK in all secondary keys; if PK is big (CHAR(36)), then all keys will be huge • InnoDB stores data in PK order; if UUID is PK and not sequential, then inserts are scattered
  42. Database Solutions • Use binary instead of string UUID •

    CHAR(16) • $uuid->getBytes() • Pull request #118: Codec to store UUID in an optimized way for InnoDB • Read Percona blog post “Store UUID in an optimized way”
  43. COMB • Combined random UUID/timestamp • Replaces the least significant

    bytes of the node field with the current timestamp • Tries to compensate for the reduced clustering in database indexes
  44. $factory = new UuidFactory(); $generator = new CombGenerator( $factory->getRandomGenerator(), $factory->getNumberConverter()

    ); $factory->setRandomGenerator($generator); $combUuid = $factory->uuid4();
  45. Override Time Generator Want to use pecl-uuid as your time

    generator? We can do that.
  46. $factory = new UuidFactory(); $factory->setTimeGenerator( new PeclUuidTimeGenerator() ); $uuid =

  47. Override Random Generator Want to use libsodium as your random

    generator? We can do that.
  48. $factory = new UuidFactory(); $factory->setRandomGenerator( new SodiumRandomGenerator() ); $uuid =

  49. More Customization In fact, you’re able to customize ramsey/uuid in

    any way you need by using interfaces and injecting dependencies in the factory: - Generators - Codecs - Converters - Providers
  50. UUID all the things?

  51. Cons • Takes up much more DB space than integer

    • By default (and spec) not sequential • Decreases database performance • Can’t use ORDER BY • Ugly in URLs
  52. Pros • Unique everywhere • Easily able to merge recordsets

    from multiple sources • Easy distribution of databases across multiple servers • May be generated anywhere, independently
  53. THANK YOU. ANY QUESTIONS? If you want to talk more,

    feel free to contact me. @ramsey Identify All the Things With UUIDs Copyright © 2016 Ben Ramsey This work is licensed under Creative Commons Attribution-ShareAlike 4.0 International. For uses not covered under this license, please contact the author. Ramsey, Ben. “Identify All the Things With UUIDs.” Dutch PHP Conference. RAI Amsterdam Convention Centre, Amsterdam. 24 Jun. 2016. Conference presentation. This presentation was created using Keynote. The text is set in Chunk Five and Helvetica Neue. The source code is set in Menlo. The iconography is provided by Font Awesome. Unless otherwise noted, all photographs are used by permission under a Creative Commons license. Please refer to the Photo Credits slide for more information. Ŏ
  54. Photo Credits 1. “38-365 Fingerprint” by Bram Cymet 2. “Baby

    Feet” by Katelyn Kenderdine 3. “Random” by Vladimer Shioshvili 4. “Hello My Name Is.... 221/365” by Robert Occhialini 5. “Curvy Road Ahead” by Kit Ng 6. “Security door” by reynermedia 7. “Hello! My Name Is JEDi.” by Tyrone J Moore 8. “Mr Anatomini” by clement127 9. “Everything” by Dan Dvorscak 10. “thinker” by Fredrik Rubensson 1 2 3 4 5 6 7 8 9 10