Judy definitely rates a WOW!!
> -----Original Message-----
> From: pgsql-hackers-owner(at)postgresql(dot)org [mailto:pgsql-hackers-
> owner(at)postgresql(dot)org] On Behalf Of Gregory Maxwell
> Sent: Friday, September 30, 2005 7:07 PM
> To: Ron Peacetree
> Cc: Jeffrey W. Baker; pgsql-hackers(at)postgresql(dot)org; pgsql-
> performance(at)postgresql(dot)org
> Subject: Re: [HACKERS] [PERFORM] A Better External Sort?
>
> On 9/28/05, Ron Peacetree <rjpeace(at)earthlink(dot)net> wrote:
> > 2= We use my method to sort two different tables. We now have these
> > very efficient representations of a specific ordering on these
tables.
> A
> > join operation can now be done using these Btrees rather than the
> > original data tables that involves less overhead than many current
> > methods.
>
> If we want to make joins very fast we should implement them using RD
> trees. For the example cases where a join against a very large table
> will produce a much smaller output, a RD tree will provide pretty much
> the optimal behavior at a very low memory cost.
>
> On the subject of high speed tree code for in-core applications, you
> should check out http://judy.sourceforge.net/ . The performance
> (insert, remove, lookup, AND storage) is really quite impressive.
> Producing cache friendly code is harder than one might expect, and it
> appears the judy library has already done a lot of the hard work.
> Though it is *L*GPLed, so perhaps that might scare some here away from
> it. :) and good luck directly doing joins with a LC-TRIE. ;)
>
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