Hi, David,
David Clarke wrote:
> On 7/6/06, Markus Schaber <schabi@logix-tt.com> wrote:
>> This is a good idea if you want to have taller indices, but you still
>> need to re-check the "real" key due to hash collisions.
>
> I am aware there are collisions with md5 but without any actual proof
> I believe the risk to be very low with the data I'm storing which is a
> kind of scrubbed free form residential address.
Then you'll have to use the re-check approach, like:
SELECT * FROM foo WHERE hashed_key = hash(mykey) && plain_key = mykey;
And then have an non-unique index on hashed_key, and probably no index n
my_key (to give the planner a hint which index to use).
HTH,
Markus
--
Markus Schaber | Logical Tracking&Tracing International AG
Dipl. Inf. | Software Development GIS
Fight against software patents in EU! www.ffii.org www.nosoftwarepatents.org
