PostgreSQL's hashing function?
Hi!
Does PostgreSQL expose its hash function? I need a fast way to hash a
string to a short code using characters in the set [A-Za-z0-9_]. (I'm not
sure yet how long this code needs to be, but I think even something as short
as length 2 may be enough.)
TIA!
Kynn
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On Fri, 22 Feb 2008 16:49:10 -0500
"Kynn Jones" <kynnjo@gmail.com> wrote:
Hi!
Does PostgreSQL expose its hash function? I need a fast way to hash a
string to a short code using characters in the set [A-Za-z0-9_].
(I'm not sure yet how long this code needs to be, but I think even
something as short as length 2 may be enough.)
Is md5 good enough? :)
select md5()
TIA!
Kynn
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Joshua D. Drake wrote:
On Fri, 22 Feb 2008 16:49:10 -0500
"Kynn Jones" <kynnjo@gmail.com> wrote:Hi!
Does PostgreSQL expose its hash function? I need a fast way to hash a
string to a short code using characters in the set [A-Za-z0-9_].Is md5 good enough? :)
Probably not. He said fast.
You could use hashtext() which is Postgres's internal hash function.
There's some possibility it could change in future versions of Postgres
though.
On Fri, Feb 22, 2008 at 8:12 PM, Greg Stark <stark@enterprisedb.com> wrote:
You could use hashtext() which is Postgres's internal hash function.
Awesome!
There's some possibility it could change in future versions of Postgres
though.
I can live with that, especially if all that changes is the implementation,
and not its availability. The use I have in mind is strictly internal, so
the possibility that a given string may get a different hashkey if
PostgreSQL gets upgraded is no problem at all.
Thanks for the pointer! It's not in the docs, so I would have never found
it on my own... (It makes me wonder what other "hidden" PostgreSQL goodies
are out there. I know, I know, peeking behind the published API is evil...
I guess I'm a geek "in a state of sin", to use von Neumann's terms...)
kynn