https://github.com/mumrah/flake-java

Id generator based on Twitter's Snowflake
https://github.com/mumrah/flake-java

Last synced: 8 months ago
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Id generator based on Twitter's Snowflake

• Host: GitHub
• URL: https://github.com/mumrah/flake-java
• Owner: mumrah
• Created: 2012-01-18T02:32:56.000Z (over 14 years ago)
• Default Branch: master
• Last Pushed: 2013-09-08T20:38:29.000Z (over 12 years ago)
• Last Synced: 2025-04-13T08:09:55.148Z (about 1 year ago)
• Language: Java
• Homepage:
• Size: 109 KB
• Stars: 104
• Watchers: 16
• Forks: 39
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

Awesome Lists containing this project

• awesome-java - Flake Java

README

          
# Unique Id generator

Based on http://blog.boundary.com/2012/01/12/Flake-A-decentralized-k-ordered-id-generation-service-in-Erlang.html

which is in turn based on Twitter's Snowflake project: http://engineering.twitter.com/2010/06/announcing-snowflake.html

Generates unique ids based on the current epoch time, current machine identity,

and a counter. The result are mostly ordered unique ids that require no

synchronization between machines.

# Compile and run

    javac -cp .:./lib/uuid-3.2.1-SNAPSHOT.jar:./lib/commons-codec-1.6.jar src/uniq/UniqueId.java

    java -cp .:./lib/uuid-3.2.1-SNAPSHOT.jar:./lib/commons-codec-1.6.jar:src uniq.UniqueId

# Performance

2011 MacBook Pro, 2.8Ghz i7

## Cat to file

    $ time java -cp .:./lib/uuid-3.2.1-SNAPSHOT.jar:./lib/commons-codec-1.6.jar:src uniq.UniqueId 10000000 > out

    

    real    0m18.498s

    user    0m5.662s

    sys     0m12.973s

    $ ls -lh out

    -rw-r--r--  1 mumrah  staff   153M May 22 10:52 out

540 id/ms

Since each id is 128 bits, the I/O rate comes out to 8640000 bytes per second, or 8.24 MB/s.

Compare this to 66.59 MB/s which is the speed that the same system can "yes > omgyes". I guess that order of

magnitude difference is the price of safety/synchronization.

## Pipe to /dev/null

    $ time java -cp .:./lib/uuid-3.2.1-SNAPSHOT.jar:./lib/commons-codec-1.6.jar:src uniq.UniqueId 10000000 > /dev/null

    real    0m7.794s

    user    0m4.688s

    sys     0m3.253s

1280 id/ms

## Pipe to fifo, fifo to /dev/null

    $ time java -cp .:./lib/uuid-3.2.1-SNAPSHOT.jar:./lib/commons-codec-1.6.jar:src uniq.UniqueId 10000000 > foo

    real    0m18.051s

    user    0m5.594s

    sys     0m12.594s

554 id/ms