Re: random() (was Re: New GUC to sample log queries)

On Wed, Dec 26, 2018 at 01:45:00PM -0500, Tom Lane wrote:
> I am not sure I buy the argument that this is a security hazard, but
> there are other reasons to question the use of random() here, some of
> which you stated yourself above.  I wonder whether we should
> establish a project policy to avoid use of random() for internal
> purposes, ie try to get to a point where drandom() is the only
> caller in the backend.

Agreed for all three points.

> A quick grep says that there's a dozen or so callers, so this patch
> certainly isn't the only offender ... but should we make an effort
> to convert them all to use, say, pg_erand48()?  I think all the
> existing callers  could happily share a process-wide random state,
> so we could make a wrapper that's no harder to use than random().

Another possibility would be to extend a bit more the use of
pg_strong_random(), though it is designed to really be used in cases
like authentication where the random bytes are strong for
cryptography.  pg_erand48() would be a good step forward.
--
Michael