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Implement SQL-compliant treatment of row comparisons for < <= > >= cases

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(previously we only did = and <> correctly).  Also, allow row comparisons
with any operators that are in btree opclasses, not only those with these
specific names.  This gets rid of a whole lot of indefensible assumptions
about the behavior of particular operators based on their names ... though
it's still true that IN and NOT IN expand to "= ANY".  The patch adds a
RowCompareExpr expression node type, and makes some changes in the
representation of ANY/ALL/ROWCOMPARE SubLinks so that they can share code
with RowCompareExpr.

I have not yet done anything about making RowCompareExpr an indexable
operator, but will look at that soon.

initdb forced due to changes in stored rules.
This commit is contained in:
Tom Lane
2005-12-28 01:30:02 +00:00
parent a37422e042
commit 6e07709760
26 changed files with 1452 additions and 659 deletions
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12
src/backend/optimizer/path/costsize.c
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@ -49,7 +49,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.151 2005/11/26 22:14:56 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.152 2005/12/28 01:29:59 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -1609,6 +1609,13 @@ cost_qual_eval_walker(Node *node, QualCost *total)
total->per_tuple +=
cpu_operator_cost * estimate_array_length(arraynode) * 0.5;
}
else if (IsA(node, RowCompareExpr))
{
/* Conservatively assume we will check all the columns */
RowCompareExpr *rcexpr = (RowCompareExpr *) node;
total->per_tuple += cpu_operator_cost * list_length(rcexpr->opnos);
}
else if (IsA(node, SubLink))
{
/* This routine should not be applied to un-planned expressions */
@ -1624,7 +1631,6 @@ cost_qual_eval_walker(Node *node, QualCost *total)
*
* An exception occurs when we have decided we can implement the
* subplan by hashing.
*
*/
SubPlan *subplan = (SubPlan *) node;
Plan *plan = subplan->plan;
@ -1643,7 +1649,7 @@ cost_qual_eval_walker(Node *node, QualCost *total)
/*
* The per-tuple costs include the cost of evaluating the lefthand
* expressions, plus the cost of probing the hashtable. Recursion
* into the exprs list will handle the lefthand expressions
* into the testexpr will handle the lefthand expressions
* properly, and will count one cpu_operator_cost for each
* comparison operator. That is probably too low for the probing
* cost, but it's hard to make a better estimate, so live with it