Re: [PATCHES] updated hash functions for postgresql v1

On Wed, 2009-10-28 at 21:09 +0200, Hannu Krosing wrote:
> Is at least the fact that they "are undocumented, have changed in the
> past, and are likely to change again in the future" documented ?

That's a little confusing to me: how do we document that something is
undocumented? And where do we stop?

> Hashing is a quite fundamental thing in computing, so I was quite
> surprised to find out it had silently changed. 

There are many reasons to use a hash, and we don't want people to use
these functions for the wrong purpose. I have seen people use a
performance hash for security purposes before, and I had to demonstrate
some hash collisions to show why that was a bad idea. So, if we do
provide documented functions, it should be done carefully.

Trying to develop and document a set of standardized, stable hash
functions covering a wide range of possible use cases sounds like it may
be better served by an extension.

Regards,Jeff Davis