38 lines
1.3 KiB
Markdown
38 lines
1.3 KiB
Markdown
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Snowflake ID generator
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======================
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This is a Go implementation of [Twitter Snowflake](https://blog.twitter.com/2010/announcing-snowflake).
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The most useful aspect of these IDs is they are _roughly_ sortable and when generated
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at roughly the same time, should have values in close proximity to each other.
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IDs
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---
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Each id will be a 64-bit number represented, structured as follows:
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```
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6 6 5 4 3 2 1
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3210987654321098765432109876543210987654321098765432109876543210
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ttttttttttttttttttttttttttttttttttttttttttmmmmmmmmmmssssssssssss
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```
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where
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* s (sequence) is a 12-bit integer that increments if called multiple times for the same millisecond
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* m (machine id) is a 10-bit integer representing the server id
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* t (time) is a 42-bit integer representing the current timestamp in milliseconds
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the number of milliseconds to have elapsed since 1491696000000 or 2017-04-09T00:00:00Z
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### String Encoding
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The 64-bit unsigned integer is base-63 encoded using the following URL-safe characters, which are ordered
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according to their ASCII value.
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```
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0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz~
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```
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A binary sort of a list of encoded values will be correctly ordered according to the numerical representation.
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