Re: Index Scans become Seq Scans after VACUUM ANALYSE

<br /><font face="sans-serif" size="2">On 04/18/2002 12:41:15 PM tycho wrote:<br /> > > Don't know if the
optimizertakes this into consideration, but a query that <br /> > uses a primary and/or unique key in the
where-clause,should always choose to <br /> > use<br /> > > the related indices (assuming the table size is
abovea certain threshold). <br /> > Since a primary key/unique index always restricts the resultset to a single <br
/>> row.....<br /> > <br /> > I don't think so.<br /> > <br /> > eg. table with primary key "pk", taking
valuesfrom 1 to 1000000 (so<br /> > 1000000 records)<br /> > <br /> > select * from table where pk > 5<br
/>> <br /> > should probably not use the index ...<br /></font><br /><font face="sans-serif" size="2">Oops,
you'reright of course. Rephrase the above as 'a query that uses a primary key to uniquely qualify a single row' (which
prettymuch restricts it to the = operator with a constant). Still, this is probably a fairly common case.....</font><br
/><br/><font face="sans-serif" size="2">Maarten</font><br /><font face="sans-serif" size="2"><br /> ----<br /><br />
MaartenBoekhold, maarten.boekhold@reuters.com<br /><br /> Reuters Consulting<br /> Dubai Media City<br /> Building 1,
5thFloor<br /> PO Box 1426<br /> Dubai, United Arab Emirates<br /> tel:+971(0)4 3918300 ext 249<br /> fax:+971(0)4
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