uuid6 2022.10.25

New time-based UUID formats which are suited for use as a database key

uuid6

New time-based UUID formats which are suited for use as a database key.

This module extends immutable UUID objects (the UUID class) with the functions uuid6(), uuid7(), and uuid8() from the IETF draft.

Install

pip install uuid6

Usage

from uuid6 import uuid6, uuid7, uuid8

my_uuid = uuid6()
print(my_uuid)
assert my_uuid < uuid6()

my_uuid = uuid7()
print(my_uuid)
assert my_uuid < uuid7()

my_uuid = uuid8()
print(my_uuid)
assert my_uuid < uuid8()

Which UUID version should I use?

Implementations SHOULD utilize UUID version 7 over UUID version 1 and 6 if possible.

UUID version 7 features a time-ordered value field derived from the widely implemented and well known Unix Epoch timestamp source, the number of milliseconds seconds since midnight 1 Jan 1970 UTC, leap seconds excluded. As well as improved entropy characteristics over versions 1 or 6.

If your use case requires greater granularity than UUID vesion 7 can provide, you might consider UUID version 8. UUID version 8 doesn't provide as good entropy characteristics as UUID version 7, but it utilizes timestamp with nanosecond level of precision.

UUIDv6 Field and Bit Layout

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                           time_high                           |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |           time_mid            |      time_low_and_version     |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |clk_seq_hi_res |  clk_seq_low  |         node (0-1)            |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                         node (2-5)                            |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

UUIDv7 Field and Bit Layout

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                           unix_ts_ms                          |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |          unix_ts_ms           |  ver  |       rand_a          |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |var|                        rand_b                             |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                            rand_b                             |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

UUIDv8 Field and Bit Layout

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                           unix_ts_ms                          |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |          unix_ts_ms           |  ver  |      subsec_a         |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |var|   subsec_b    |         rand                              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
        |                             rand                              |
        +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

• unix_ts_ms: 48 bit big-endian unsigned number of Unix epoch timestamp with millisecond level of precision
• ver: The 4 bit UUIDv8 version (1000)
• subsec_a: 12 bits allocated to sub-second precision values
• var: 2 bit UUID variant (10)
• subsec_b: 8 bits allocated to sub-second precision values
• rand: The remaining 54 bits are filled with cryptographically strong random data

20 extra bits dedicated to sub-second precision provide nanosecond resolution. The unix_ts_ms, subsec_a, and subsec_b fields guarantee the order of UUIDs generated within the same nanosecond by monotonically incrementing the timer.

Performance

Run the shell script bench.sh to test on your own machine.

Results

MacBook Air 2020

Python 3.10.4
Mean +- std dev: 870 ns +- 11 ns
Mean +- std dev: 1.17 us +- 0.01 us
Mean +- std dev: 2.18 us +- 0.02 us
Mean +- std dev: 1.60 us +- 0.02 us
Mean +- std dev: 1.78 us +- 0.02 us
+-----------+--------+-----------------------+-----------------------+-----------------------+-----------------------+
| Benchmark | uuid1  | uuid4                 | uuid6                 | uuid7                 | uuid8                 |
+===========+========+=======================+=======================+=======================+=======================+
| timeit    | 870 ns | 1.17 us: 1.35x slower | 2.18 us: 2.51x slower | 1.60 us: 1.84x slower | 1.78 us: 2.04x slower |
+-----------+--------+-----------------------+-----------------------+-----------------------+-----------------------+