From: Tom Lane <tgl@sss.pgh.pa.us>
To: Madison Kelly <linux@alteeve.com>
Cc: Tobias Brox <tobias@nordicbet.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Index ot being used
Date: Sun, 12 Jun 2005 11:56:23 -0400
Message-ID: <24636.1118591783@sss.pgh.pa.us> (raw)
In-Reply-To: <42AC42CB.8050703@alteeve.com>
References: <1825.216.209.137.1.1118419819.squirrel@mail.alteeve.com>
<20050610155535.GO8451@tobias.nordicbet.com>
<42AC42CB.8050703@alteeve.com>
Madison Kelly <linux@alteeve.com> writes:
> Here is my full query:
> tle-bu=> EXPLAIN ANALYZE SELECT file_name, file_parent_dir, file_type
> FROM file_info_7 WHERE file_type='d' ORDER BY file_parent_dir ASC,
> file_name ASC;
> This is my index (which I guess is wrong):
> tle-bu=> \d file_info_7_display_idx
> Index "public.file_info_7_display_idx"
> Column | Type
> -----------------+----------------------
> file_type | character varying(2)
> file_parent_dir | text
> file_name | text
> btree, for table "public.file_info_7"
The index is fine, but you need to phrase the query as
... ORDER BY file_type, file_parent_dir, file_name;
(Whether you use ASC or not doesn't matter.) Otherwise the planner
won't make the connection to the sort ordering of the index.
regards, tom lane
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To: pgsql-performance@postgresql.org
Cc: tgl@sss.pgh.pa.us, linux@alteeve.com, tobias@nordicbet.com
Subject: Re: Index ot being used
In-Reply-To: <24636.1118591783@sss.pgh.pa.us>
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