From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
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To: | Alexander Korotkov <aekorotkov(at)gmail(dot)com> |
Cc: | teodor(at)sigaev(dot)ru, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: knngist - 0.8 |
Date: | 2010-08-09 18:32:09 |
Message-ID: | AANLkTin9QBrxbcjG4Dmbsv0u-xHEfqmQDSCo+PNRh1A0@mail.gmail.com |
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Lists: | pgsql-hackers |
On Sun, Aug 8, 2010 at 4:28 PM, Alexander Korotkov <aekorotkov(at)gmail(dot)com> wrote:
> In gist consitent method support only filtering strategies. For such
> strategies consistent method returns true if subtree can contain matching
> node and false otherwise. Knngist introduce also order by strategies. For
> filtering strategies knngist consistent method returns 0 if subtree can
> contain matching node and -1 otherwise. For order by strategies knngist
> consistent method returns minimal possible distance in subtree. I think we
> can use consistent method with order by strategies not only for ordering but
> also for filtering. If query contain assertion that distance is less than
> some value, than we can call consistent method with order by strategy and
> compare result with query value in order to determine whether scan subtree.
I am not an expert on this code, but after thinking this over, I
believe you are correct and that this is a good point.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company
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