Re: gaussian distribution pgbench

Hello Mitsumasa,

> In the general transaction situation, clients access for all records equally is
> hard to happen. I think gaussian distribution access patterns are most of
> transaction petterns in general. My patch realizes neary this access pattern.

That is great! I was just looking for something like that!

I have not looked at the patch yet, but from the plots you sent, it seems
that it is a gaussian distribution over the keys. However this pattern
induces stronger cache effects which are maybe not too realistic, because
neighboring keys in the middle are more likely to be chosen.

It seems to me that this is not desirable.

Have you considered adding a "randomization" layer, that is once you have
a key in [1 .. n] centered around n/2, then you perform a pseudo-random
transformation into the same domain so that key values are scattered over
the whole domain?

--
Fabien.