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Commit34f8ee9

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Add selectivity-calculation code for RowCompareExpr nodes. Simplistic,
but a lot better than nothing at all ...
1 parent39fc1fb commit34f8ee9

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3 files changed

+73
-3
lines changed

3 files changed

+73
-3
lines changed

‎src/backend/optimizer/path/clausesel.c

Lines changed: 9 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/optimizer/path/clausesel.c,v 1.76 2005/11/25 19:47:49 tgl Exp $
11+
* $PostgreSQL: pgsql/src/backend/optimizer/path/clausesel.c,v 1.77 2006/01/14 00:14:11 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -663,6 +663,14 @@ clause_selectivity(PlannerInfo *root,
663663
varRelid,
664664
jointype);
665665
}
666+
elseif (IsA(clause,RowCompareExpr))
667+
{
668+
/* Use node specific selectivity calculation function */
669+
s1=rowcomparesel(root,
670+
(RowCompareExpr*)clause,
671+
varRelid,
672+
jointype);
673+
}
666674
elseif (IsA(clause,NullTest))
667675
{
668676
/* Use node specific selectivity calculation function */

‎src/backend/utils/adt/selfuncs.c

Lines changed: 60 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -15,7 +15,7 @@
1515
*
1616
*
1717
* IDENTIFICATION
18-
* $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.195 2006/01/10 17:35:52 tgl Exp $
18+
* $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.196 2006/01/14 00:14:11 tgl Exp $
1919
*
2020
*-------------------------------------------------------------------------
2121
*/
@@ -1566,6 +1566,65 @@ scalararraysel(PlannerInfo *root,
15661566
returns1;
15671567
}
15681568

1569+
/*
1570+
*rowcomparesel- Selectivity of RowCompareExpr Node.
1571+
*
1572+
* We estimate RowCompare selectivity by considering just the first (high
1573+
* order) columns, which makes it equivalent to an ordinary OpExpr. While
1574+
* this estimate could be refined by considering additional columns, it
1575+
* seems unlikely that we could do a lot better without multi-column
1576+
* statistics.
1577+
*/
1578+
Selectivity
1579+
rowcomparesel(PlannerInfo*root,
1580+
RowCompareExpr*clause,
1581+
intvarRelid,JoinTypejointype)
1582+
{
1583+
Selectivitys1;
1584+
Oidopno=linitial_oid(clause->opnos);
1585+
List*opargs;
1586+
boolis_join_clause;
1587+
1588+
/* Build equivalent arg list for single operator */
1589+
opargs=list_make2(linitial(clause->largs),linitial(clause->rargs));
1590+
1591+
/* Decide if it's a join clause, same as for OpExpr */
1592+
if (varRelid!=0)
1593+
{
1594+
/*
1595+
* If we are considering a nestloop join then all clauses are
1596+
* restriction clauses, since we are only interested in the one
1597+
* relation.
1598+
*/
1599+
is_join_clause= false;
1600+
}
1601+
else
1602+
{
1603+
/*
1604+
* Otherwise, it's a join if there's more than one relation used.
1605+
* Notice we ignore the low-order columns here.
1606+
*/
1607+
is_join_clause= (NumRelids((Node*)opargs)>1);
1608+
}
1609+
1610+
if (is_join_clause)
1611+
{
1612+
/* Estimate selectivity for a join clause. */
1613+
s1=join_selectivity(root,opno,
1614+
opargs,
1615+
jointype);
1616+
}
1617+
else
1618+
{
1619+
/* Estimate selectivity for a restriction clause. */
1620+
s1=restriction_selectivity(root,opno,
1621+
opargs,
1622+
varRelid);
1623+
}
1624+
1625+
returns1;
1626+
}
1627+
15691628
/*
15701629
*eqjoinsel- Join selectivity of "="
15711630
*/

‎src/include/utils/selfuncs.h

Lines changed: 4 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
99
* Portions Copyright (c) 1994, Regents of the University of California
1010
*
11-
* $PostgreSQL: pgsql/src/include/utils/selfuncs.h,v 1.26 2005/11/25 19:47:50 tgl Exp $
11+
* $PostgreSQL: pgsql/src/include/utils/selfuncs.h,v 1.27 2006/01/14 00:14:12 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -116,6 +116,9 @@ extern Selectivity scalararraysel(PlannerInfo *root,
116116
ScalarArrayOpExpr*clause,
117117
boolis_join_clause,
118118
intvarRelid,JoinTypejointype);
119+
externSelectivityrowcomparesel(PlannerInfo*root,
120+
RowCompareExpr*clause,
121+
intvarRelid,JoinTypejointype);
119122

120123
externvoidmergejoinscansel(PlannerInfo*root,Node*clause,
121124
Selectivity*leftscan,

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