From: Tom Lane <tgl@sss.pgh.pa.us>
To: Vellinga, Fred <fred.vellinga@nl.verizonbusiness.com>
Cc: 'pgsql-sql@postgresql.org' <pgsql-sql@postgresql.org>
Subject: Re: Special meaning of NL string
Date: Mon, 10 Apr 2006 22:57:57 -0400
Message-ID: <3250.1144724277@sss.pgh.pa.us> (raw)
In-Reply-To: <DB8373C85B90D71191350008C784C7390306AF67@ms-ams-exch02.nl.mcilink.com>
References: <DB8373C85B90D71191350008C784C7390306AF67@ms-ams-exch02.nl.mcilink.com>
"Vellinga, Fred" <fred.vellinga@nl.verizonbusiness.com> writes:
> The query
> SELECT COUNT(*) FROM Table WHERE Field1 = 'NL' OR Field2 = 'NL'
> does a sequence scan instead of an index scan, and is thus very slow. If I
> replace NL by BE (Belgium) the query does an index scan.
Probably, 'NL' is a lot more common than 'BE' in your table ... the
planner does examine statistics while deciding what sort of scan to use.
regards, tom lane
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To: pgsql-sql@postgresql.org
Cc: tgl@sss.pgh.pa.us, fred.vellinga@nl.verizonbusiness.com
Subject: Re: Special meaning of NL string
In-Reply-To: <3250.1144724277@sss.pgh.pa.us>
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