simpleflake-java
Simpleflake aims to create a Twitter Snowflake compatible identifier without coordination between generators.
The result is a signed 64 bit long broken down as follows
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bit 64 - Sign just like in java
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bit 63-23 - Timestamp in millisecons utilizing same arbritray EPOCH as twiiter(1288834974657L) or Thu, 04 Nov 2010 01:42:54 GMT
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bit 22-1 - Random bits
While this does not provide exact ordering it does provide ordering by the millisecond. ID’s generated within the same millisecond will be random.
Care must be taken to ensure the server has accurate time (ntp).
While duplicates are prevented when utilizing a single instance, if multiple instances are created either in the same or different VM’s collisions are possible though unlikely at low insert rates. Once/if collisions becomes an issue you can gracefully migrate to Twitter snowflake since the EPOCH and format are the same.
Simpleflake for Java is inspired by Simpleflake for Python.