What is the difference between the following two functions
gen_random_uuid()provided bypgcryptoextensionuuid_generate_v4()provided byuuid-osspextension
Are they both the same behind the scenes? Any performance impacts on using one?
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NO WAR WITH RUSSIA
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1good question and welcome to [dba.se]. I would look into it, but I'm going to sleep maybe tomorrow. =) – NO WAR WITH RUSSIA May 05 '18 at 06:04
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Are they the same?
No.
The Postgres documetation for uuid-ossp suggests using gen_random_uuid() If you only need randomly-generated (version 4) UUIDs,
The uuid-ossp extension also provides other types of UUID (such as mac-addresses based)
The difference?
I looked at the source and discovered that
uuid_generate_v4()uses arc4random to determine the random part.gen_random_uuid()uses fortuna instead.
Other than that they do the same job.
Basil Bourque
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Jasen
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3arc4random vs. fortuna, why should you care? As best I can tell arc4random *could* have some vulnerabilities. Fortuna appears to be more secure. https://en.wikipedia.org/wiki/Fortuna_(PRNG) https://en.wikipedia.org/wiki/RC4#RC4-based_random_number_generators https://security.stackexchange.com/questions/85601/is-arc4random-secure-enough/172905#172905 – HairOfTheDog Jun 25 '21 at 02:54