Re: Guarantee uniqueness of PGP key

good grief

yeah, look at using the MD5 or SHA1 hash of the key itself

-d

On Mon, 20 May 2002, andre wrote:

> Hi,
> 
> More generically, how do I best guarantee that any large varchar is unique 
> before inserting?
> 
> In my application, I need to ensure that each e-mail address and 
> corresponding PGP public key are both unique.
> 
> I originally implemented this by adding a uniqueness contrainst to both 
> columns.  easy.
> 
> The problem is that some PGP keys are over 2713 bytes, and postgres (7.2) 
> gives the error:
> 
> ERROR: btree: index item size 4336 exceeds maximum 2713
> 
> I thought perhaps I could use a hash or rtree index, but neither of them work 
> for unique-ness.
> 
> I saw in another posting that it may be possible to raise this limit to 8k or 
> so, but I don't want to do this because 1) it requires a recompile of 
> postgres (and rollout to dev, stage, prod machines), and 2) a key could 
> theoretically be longer than 8k anyway.
> 
> I can guarantee unique-ness by removing the index and doing a select before 
> the insert.  If there is a matching row, then I am trying to insert a dup. 
> bail.
> 
> My concern is that doing this without an index will be monumentally slow for 
> any large-ish number of keys.
> 
> Any bright ideas? All suggestions appreciated.
> 
> /andre
> 
> 
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