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

On Wed, Dec 26, 2018 at 11:46 AM Peter Geoghegan <pg@bowt.ie> wrote:
> > There might well be debugging value in affecting internal PRNG usages,
> > but let's please not think it's a good idea that that's trivially
> > reachable from SQL.
>
> I hesitate to say that there is much value beyond the value that I've
> found in this one instance. Maybe the remaining cases where this
> technique could be applied just aren't very interesting.

Actually, it looks like there may be several cases that are quite
similar to the "getting tired" case that I took an interest in. You
have spgdoinsert(), gistchoose(), and gin_rand()/dropItem(), just for
starters -- those all seem to affect the final structure of an index.
I'm beginning to think that the technique that I came up with to make
"getting tired" deterministic ought to be supporting as a debugging
option if we're to do away with internal use of the generic/seedable
backend PRNG.

-- 
Peter Geoghegan