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Reduce eqsel()'s fudge-factor for estimating the frequency of values

other than the most common value in a column. We had had 0.5, make it0.1 to make it more likely that an indexscan will be chosen. Reallyneed better statistics instead, but this should stem the bleedingmeanwhile ...

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src/backend/utils/adt
- selfuncs.c

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-3

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`‎src/backend/utils/adt/selfuncs.c`

Lines changed: 6 additions & 3 deletions

Original file line number	Diff line number	Diff line change
`@@ -15,7 +15,7 @@`
`15`	`15`	`*`
`16`	`16`	`*`
`17`	`17`	`* IDENTIFICATION`
`18`		`- * $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.65 2000/04/16 04:41:02 tgl Exp $`
	`18`	`+ * $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.66 2000/05/26 17:19:15 tgl Exp $`
`19`	`19`	`*`
`20`	`20`	`*-------------------------------------------------------------------------`
`21`	`21`	`*/`
`@@ -55,6 +55,9 @@`
`55`	`55`	`/* default selectivity estimate for pattern-match operators such as LIKE */`
`56`	`56`	`#defineDEFAULT_MATCH_SEL0.01`
`57`	`57`
	`58`	`+/* "fudge factor" for estimating frequency of not-most-common values */`
	`59`	`+#defineNOT_MOST_COMMON_RATIO 0.1`
	`60`	`+`
`58`	`61`	`staticboolconvert_to_scalar(Datumvalue,Oidvaluetypid,double*scaledvalue,`
`59`	`62`	`Datumlobound,Datumhibound,Oidboundstypid,`
`60`	`63`	`doublescaledlobound,doublescaledhibound);`
`@@ -190,7 +193,7 @@ eqsel(Oid opid,`
`190`	`193`	`* exactly!`
`191`	`194`	`*/`
`192`	`195`	`if (typid!=BOOLOID)`
`193`		`-selec *=0.5;`
	`196`	`+selec *=NOT_MOST_COMMON_RATIO;`
`194`	`197`	`}`
`195`	`198`	`}`
`196`	`199`	`else`
`@@ -209,7 +212,7 @@ eqsel(Oid opid,`
`209`	`212`	`* and in fact it's probably less, so apply a fudge`
`210`	`213`	`* factor.`
`211`	`214`	`*/`
`212`		`-selec *=0.5;`
	`215`	`+selec *=NOT_MOST_COMMON_RATIO;`
`213`	`216`	`}`
`214`	`217`
`215`	`218`	`/* result should be in range, but make sure... */`

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Commitb71761d

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`‎src/backend/utils/adt/selfuncs.c`

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