Shulou(Shulou.com)06/02 Report--

This article mainly explains "how to use data to generate Sequence in database". Interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let the editor take you to learn how to use data to generate Sequence in a database.

1. Snowflake algorithm

Twitter's open source distributed id generation algorithm uses 64-bit long-type id.

41 bit, timestamp, in milliseconds. 2 ^ 41-1 converts adults to 69 years.

10 bit, of which 5 represent computer room and 5 represent machine ID

12 bit, recording different id generated in the same millisecond, 2 ^ 12-1 = 4096, which can represent 4096 different id in the same millisecond

Support tens of thousands of concurrent messages per second.

Public class UniqueOrderGenerate {/ / = = Fields===/** start time cut (2018-07-03) * / private final long twepoch = 1530607760000L * number of bits occupied by machine id * / private final long workerIdBits = 5L * number of digits occupied by data identifier id * / private final long datacenterIdBits = 5L / * * the largest machine supported, id, the result is 31 (this shift algorithm can quickly calculate the maximum decimal number that several binary numbers can represent) * / private final long maxWorkerId =-1L ^ (- 1L)

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