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Repair error noticed by Roberto Cornacchia: selectivity code

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was rejecting negative attnums as bogus, which of course they are not.
Add code to get_attdisbursion to produce a useful value for OID attribute,
since VACUUM does not store stats for system attributes.
Also, repair bug that's been in eqjoinsel for a long time: it was taking
the max of the two columns' disbursions, whereas it should use the min.
This commit is contained in:
Tom Lane
1999-09-09 02:36:04 +00:00
parent 45500964f6
commit 51db6455ea
5 changed files with 67 additions and 38 deletions
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28
src/backend/optimizer/util/clauses.c
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@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.50 1999/08/26 05:09:05 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.51 1999/09/09 02:35:53 tgl Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@@ -116,7 +116,10 @@ make_opclause(Oper *op, Var *leftop, Var *rightop)
*
* Returns the left operand of a clause of the form (op expr expr)
* or (op expr)
* NB: it is assumed (for now) that all expr must be Var nodes
*
* NB: for historical reasons, the result is declared Var *, even
* though many callers can cope with results that are not Vars.
* The result really ought to be declared Expr * or Node *.
*/
Var *
get_leftop(Expr *clause)
@@ -549,8 +552,11 @@ NumRelids(Node *clause)
* if the "something" is a constant, the value of the constant
* flags indicating whether a constant was found, and on which side.
* Default values are returned if the expression is too complicated,
* specifically -1 for the relid and attno, 0 for the constant value.
* Note that InvalidAttrNumber is *not* -1, but 0.
* specifically 0 for the relid and attno, 0 for the constant value.
*
* Note that negative attno values are *not* invalid, but represent
* system attributes such as OID. It's sufficient to check for relid=0
* to determine whether the routine succeeded.
*/
void
get_relattval(Node *clause,
@@ -610,8 +616,8 @@ get_relattval(Node *clause,
{
/* Duh, it's too complicated for me... */
default_results:
*relid = -1;
*attno = -1;
*relid = 0;
*attno = 0;
*constval = 0;
*flag = 0;
return;
@@ -663,7 +669,7 @@ static int is_single_func(Node *node)
* for a joinclause.
*
* If the clause is not of the form (var op var) or if any of the vars
* refer to nested attributes, then -1's are returned.
* refer to nested attributes, then zeroes are returned.
*
*/
void
@@ -674,10 +680,10 @@ get_rels_atts(Node *clause,
AttrNumber *attno2)
{
/* set default values */
*relid1 = -1;
*attno1 = -1;
*relid2 = -1;
*attno2 = -1;
*relid1 = 0;
*attno1 = 0;
*relid2 = 0;
*attno2 = 0;
if (is_opclause(clause))
{