Re: Document hashtext() and Friends? - Mailing list pgsql-hackers

From ktm@rice.edu
Subject Re: Document hashtext() and Friends?
Date
Msg-id 20120221203059.GE21114@aart.rice.edu
Whole thread Raw
In response to Re: Document hashtext() and Friends?  ("David E. Wheeler" <david@justatheory.com>)
List pgsql-hackers
On Tue, Feb 21, 2012 at 12:14:03PM -0800, David E. Wheeler wrote:
> On Feb 21, 2012, at 12:11 PM, Michael Glaesemann wrote:
>
> > And hashtext *has* changed across versions, which is why Peter Eisentraut published a version-independent hash
functionlibrary: https://github.com/petere/pgvihash 
>
> Yes, Marko wrote one, too:
>
>   https://github.com/markokr/pghashlib
>
> But as I’m about to build a system that is going to have many billions of nodes, I could use a variant that returns a
bigint.Anyone got a pointer to something like that? 
>
> Thanks,
>
> David
>

Hi David,

The existing hash_any() function can return a 64-bit hash, instead of the current
32-bit hash, by returning the b and c values, instead of the current which just
returns the c value, per the comment at the start of the function. It sounded like
Peter had already done this in his pg_stat_statements normalization patch, but I
could not find it.

Regards,
Ken


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