假设我要创建一个表 foo ,该表的列 bar 应该是一个非常大的随机整数。
Let's say I'm creating a table foo with a column bar that should be a very large random integer.
CREATE TABLE foo ( bar bigint DEFAULT round(((9223372036854775807::bigint)::double precision * random())) NOT NULL, baz text );这是最好的方法吗?谁能说出PostgreSQL random()函数的质量?
Is this the best way to do this? Can anyone speak to the quality of PostgreSQL's random() function? Is the multiplication here masking the entropy?
请注意,我做具有良好的硬件熵,它们可以馈入 / dev / random中? 。
Note that I do have good hardware entropy feeding into /dev/random.
推荐答案Postgresql随机基于自己的 erand48 便携式实现 >。这是在48位域中的线性同余PRNG 。
Postgresql random is based on their own portable implementation of POSIX erand48. It's a linear congruential PRNG in a 48 bit domain.
如果您需要更强大的功能,请查看pg_crypto模块的 gen_random_bytes 函数,该函数用于通过密码生成强熵。
If you need something stronger look to the pg_crypto module's gen_random_bytes function which is used to produce cryptographically strong entropy.
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PostgreSQL的random()函数的质量?
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