d691ae27b1
This is passed the UBID type as an integer, which you can determine
via `UBID.to_base32_n` (e.g. `UBID.to_base32_n("vm") # => 884`)
This could be used as the DEFAULT value for UUID primary keys.
45 lines
1.4 KiB
Ruby
45 lines
1.4 KiB
Ruby
# frozen_string_literal: true
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Sequel.migration do
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up do
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# This function generates a pure-random (not timestamp-based) UUID,
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# that is in valid UBID format. It is passed the UBID type as an integer.
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# You can get the type integer using `UBID.to_base32_n(prefix)`
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# (e.g. `UBID.to_base32_n("vm") # => 884`).
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#
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# This could be used in the future as the DEFAULT value for uuid primary
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# keys.
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run <<~SQL
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CREATE FUNCTION gen_random_ubid_uuid(ubid_type int) RETURNS uuid AS $$
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DECLARE
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r0 bigint;
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r1 int;
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r2 int;
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r3 bigint;
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p1 text;
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p2 text;
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BEGIN
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-- 48 bit random
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r0 = floor(281474976710656 * random()::numeric)::bigint;
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-- 4 bit version + 2 bit random + 10 bit type
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r1 = ((32 + floor(4 * random()::numeric)::integer) << 10) | ubid_type;
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-- 2 bit variant + 2 bit random
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r2 = 8 + floor(4 * random()::numeric)::integer;
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-- 60 bit random
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r3 = floor(1152921504606846976 * random()::numeric)::bigint;
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p1 = lpad(to_hex(r0), 12, '0');
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p2 = lpad(to_hex(r3), 15, '0');
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RETURN (substr(p1, 1, 8) || '-' || substr(p1, 9, 4) || '-' || lpad(to_hex(r1), 4, '0') || '-' || to_hex(r2) || substr(p2, 1, 3) || '-' || substr(p2, 4, 12))::uuid;
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END
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$$ LANGUAGE plpgsql;
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SQL
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end
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down do
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run "DROP FUNCTION gen_random_ubid_uuid(int)"
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end
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end
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