From: Teodor Sigaev <teodor@sigaev.ru>
To: Pgsql Hackers <pgsql-hackers@postgresql.org>
Subject: Re: KNNGiST for knn-search (WIP)
Date: Fri, 27 Nov 2009 18:23:50 +0300
Message-ID: <4B0FEF06.5050703@sigaev.ru> (raw)
In-Reply-To: <4B0EAE0D.606@sigaev.ru>
References: <4B0AC9E1.5050509@sigaev.ru>
<4B0EAE0D.606@sigaev.ru>
> Planner (find_usable_indexes function, actually) could push pathkey
> expression into restriction clauses of index. I'm not fully satisfied
> with this piece of code, but, may be, someone has a better idea. I
> though about adding separate indexorderquals in IndexPath structure...
Done, IndexScan and IndexPath have separate field to store order clauses. That's
allowed to improve explain output:
# EXPLAIN (COSTS OFF)
SELECT * FROM point_tbl WHERE f1 <@ '(-10,-10),(10,10)':: box ORDER BY f1 <->
'0,1';
QUERY PLAN
------------------------------------------------
Index Scan using gpointind on point_tbl
Index Cond: (f1 <@ '(10,10),(-10,-10)'::box)
Sort Cond: (f1 <-> '(0,1)'::point)
(3 rows)
We are waiting feedback to choose a way of planner support of knn-search.
Still TODO:
- cost of index scan
- Sort condition should not be ANDed in explain output
- current patch remove support of IndexScanDesc->kill_prior_tuple, it's needed
to restore support if it will not create too big overhead
- documentation
--
Teodor Sigaev E-mail: teodor@sigaev.ru
WWW: http://www.sigaev.ru/Attachments:
builtin_knngist-0.4.1.gz (application/x-tar, 26.9K) download
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To: pgsql-hackers@postgresql.org
Cc: teodor@sigaev.ru
Subject: Re: KNNGiST for knn-search (WIP)
In-Reply-To: <4B0FEF06.5050703@sigaev.ru>
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