KSUID generators

These functions return 27-character text values using the base62 alphabet 0-9, A-Z, a-z. Use text collate "C" for byte-order comparisons. Both read clock_timestamp() and use random(); the sizes of their random fields are not claims of equivalent random entropy.

gen_random_ksuid_second

extensions.gen_random_ksuid_second() → text

Combines a seconds field relative to Unix epoch value 1400000000 (2014-05-13 16:53:20 UTC) with a 128-bit payload assembled from three calls to random(), then encodes and pads the result to 27 base62 characters.

Guarantees: for current timestamps within the format’s range, produces a fixed-width base62 string suitable for a text column default.

Does not guarantee: uniqueness, cryptographic unpredictability or ordering of calls within a second. The seconds field is rounded, not floored. The function does not explicitly guard the 32-bit seconds range; see errors and limits.

select length(extensions.gen_random_ksuid_second());
-- 27

gen_random_ksuid_microsecond

extensions.gen_random_ksuid_microsecond() → text

Uses the same epoch and encoding, with 20 bits for microseconds and a 108-bit random payload assembled from two calls to random(). This is the extension’s microsecond variant; a conventional KSUID decoder treats those microsecond bits as part of the payload.

Guarantees: for current timestamps within the format’s range, produces a 27-character base62 string with an additional time field.

Does not guarantee: uniqueness, cryptographic unpredictability, strict monotonicity or exact microsecond ordering. The seconds field is rounded before the microseconds field is added.

select length(extensions.gen_random_ksuid_microsecond());
-- 27

The extension exposes no KSUID decoder or validator. Use primary keys for table defaults and collation examples.