A couple of comments:
* There should be an explicit "\setrandom ... uniform" option too, even
though you get that implicitly if you don't specify the distribution
Indeed. I agree. I suggested it, but it got lost.
* What exactly does the "threshold" mean? The docs informally explain that
"the larger the thresold, the more frequent values close to the middle of the
interval are drawn", but that's pretty vague.
There are explanations and computations as comments in the code. If it is
about the documentation, I'm not sure that a very precise mathematical
definition will help a lot of people, and might rather hinder
understanding, so the doc focuses on an intuitive explanation instead.
* Does min and max really make sense for gaussian and exponential
distributions? For gaussian, I would expect mean and standard deviation as
the parameters, not min/max/threshold.
Yes... and no:-) The aim is to draw an integer primary key from a table,
so it must be in a specified range. This is approximated by drawing a
double value with the expected distribution (gaussian or exponential) and
project it carefully onto integers. If it is out of range, there is a loop
and another value is drawn. The minimal threshold constraint (2.0) ensures
that the probability of looping is low.
* How about setting the variable as a float instead of integer? Would seem
more natural to me. At least as an option.
Which variable? The values set by setrandom are mostly used for primary
keys. We really want integers in a range.
Sent via pgsql-hackers mailing list (email@example.com)
To make changes to your subscription: