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Another round of planner/optimizer work. This is just restructuring and

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code cleanup; no major improvements yet.  However, EXPLAIN does produce
more intuitive outputs for nested loops with indexscans now...
This commit is contained in:
Tom Lane
2000-01-09 00:26:47 +00:00
parent 69d4299e3e
commit 166b5c1def
35 changed files with 1239 additions and 1448 deletions
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21
src/backend/utils/adt/selfuncs.c
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@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.44 1999/11/25 00:21:34 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.45 2000/01/09 00:26:20 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -36,6 +36,9 @@
/* are we looking at a functional index selectivity request? */
#define FunctionalSelectivity(nIndKeys,attNum) ((attNum)==InvalidAttrNumber)
/* default selectivity estimate for equalities such as "A = b" */
#define DEFAULT_EQ_SEL 0.01
/* default selectivity estimate for inequalities such as "A < b" */
#define DEFAULT_INEQ_SEL (1.0 / 3.0)
@ -75,7 +78,7 @@ eqsel(Oid opid,
result = (float64) palloc(sizeof(float64data));
if (NONVALUE(attno) || NONVALUE(relid))
*result = 0.1;
*result = DEFAULT_EQ_SEL;
else
{
Oid typid;
@ -369,15 +372,16 @@ eqjoinsel(Oid opid,
float64data num1,
num2,
min;
bool unknown1 = NONVALUE(relid1) || NONVALUE(attno1);
bool unknown2 = NONVALUE(relid2) || NONVALUE(attno2);
result = (float64) palloc(sizeof(float64data));
if (NONVALUE(attno1) || NONVALUE(relid1) ||
NONVALUE(attno2) || NONVALUE(relid2))
*result = 0.1;
if (unknown1 && unknown2)
*result = DEFAULT_EQ_SEL;
else
{
num1 = get_attdisbursion(relid1, attno1, 0.01);
num2 = get_attdisbursion(relid2, attno2, 0.01);
num1 = unknown1 ? 1.0 : get_attdisbursion(relid1, attno1, 0.01);
num2 = unknown2 ? 1.0 : get_attdisbursion(relid2, attno2, 0.01);
/*
* The join selectivity cannot be more than num2, since each
* tuple in table 1 could match no more than num2 fraction of
@ -386,6 +390,9 @@ eqjoinsel(Oid opid,
* less). By the same reasoning it is not more than num1.
* The min is therefore an upper bound.
*
* If we know the disbursion of only one side, use it; the reasoning
* above still works.
*
* XXX can we make a better estimate here? Using the nullfrac
* statistic might be helpful, for example. Assuming the operator
* is strict (does not succeed for null inputs) then the selectivity