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-rw-r--r--src/backend/optimizer/util/clauses.c188
1 files changed, 89 insertions, 99 deletions
diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c
index 26ca6733590..d615d4e36d6 100644
--- a/src/backend/optimizer/util/clauses.c
+++ b/src/backend/optimizer/util/clauses.c
@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.29 1999/02/13 23:16:42 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.30 1999/02/14 22:24:25 tgl Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@@ -101,7 +101,10 @@ make_opclause(Oper *op, Var *leftop, Var *rightop)
expr->typeOid = InvalidOid; /* assume type checking done */
expr->opType = OP_EXPR;
expr->oper = (Node *) op;
- expr->args = makeList(leftop, rightop, -1);
+ if (rightop)
+ expr->args = lcons(leftop, lcons(rightop, NIL));
+ else
+ expr->args = lcons(leftop, NIL);
return expr;
}
@@ -125,7 +128,7 @@ get_leftop(Expr *clause)
* get_rightop
*
* Returns the right operand in a clause of the form (op expr expr).
- *
+ * NB: result will be NULL if applied to a unary op clause.
*/
Var *
get_rightop(Expr *clause)
@@ -470,6 +473,9 @@ is_joinable(Node *clause)
leftop = (Node *) get_leftop((Expr *) clause);
rightop = (Node *) get_rightop((Expr *) clause);
+ if (!rightop)
+ return false; /* unary opclauses need not apply */
+
/*
* One side of the clause (i.e. left or right operands) must either be
* a var node ...
@@ -491,19 +497,27 @@ is_joinable(Node *clause)
*
* Returns t iff 'clause' is a valid qualification clause.
*
+ * For now we accept only "var op const" or "const op var".
*/
bool
qual_clause_p(Node *clause)
{
+ Node *leftop,
+ *rightop;
+
if (!is_opclause(clause))
return false;
+ leftop = (Node *) get_leftop((Expr *) clause);
+ rightop = (Node *) get_rightop((Expr *) clause);
+
+ if (!rightop)
+ return false; /* unary opclauses need not apply */
+
/* How about Param-s ? - vadim 02/03/98 */
- if (IsA(get_leftop((Expr *) clause), Var) &&
- IsA(get_rightop((Expr *) clause), Const))
+ if (IsA(leftop, Var) && IsA(rightop, Const))
return true;
- else if (IsA(get_rightop((Expr *) clause), Var) &&
- IsA(get_leftop((Expr *) clause), Const))
+ if (IsA(rightop, Var) && IsA(leftop, Const))
return true;
return false;
}
@@ -618,42 +632,35 @@ get_relattval(Node *clause,
Datum *constval,
int *flag)
{
- Var *left = get_leftop((Expr *) clause);
- Var *right = get_rightop((Expr *) clause);
+ Var *left,
+ *right;
- if (is_opclause(clause) && IsA(left, Var) &&
- IsA(right, Const))
- {
+ /* Careful; the passed clause might not be a binary operator at all */
- if (right != NULL)
- {
+ if (!is_opclause(clause))
+ goto default_results;
- *relid = left->varno;
- *attno = left->varattno;
- *constval = ((Const *) right)->constvalue;
- *flag = (_SELEC_CONSTANT_RIGHT_ | _SELEC_IS_CONSTANT_);
+ left = get_leftop((Expr *) clause);
+ right = get_rightop((Expr *) clause);
- }
- else
- {
+ if (!right)
+ goto default_results;
- *relid = left->varno;
- *attno = left->varattno;
- *constval = 0;
- *flag = (_SELEC_CONSTANT_RIGHT_ | _SELEC_NOT_CONSTANT_);
-
- }
+ if (IsA(left, Var) && IsA(right, Const))
+ {
+ *relid = left->varno;
+ *attno = left->varattno;
+ *constval = ((Const *) right)->constvalue;
+ *flag = (_SELEC_CONSTANT_RIGHT_ | _SELEC_IS_CONSTANT_);
}
- else if (is_opclause(clause) && IsA(left, Var) &&IsA(right, Param))
+ else if (IsA(left, Var) && IsA(right, Param))
{
*relid = left->varno;
*attno = left->varattno;
*constval = 0;
*flag = (_SELEC_NOT_CONSTANT_);
}
- else if (is_opclause(clause) &&
- is_funcclause((Node *) left) &&
- IsA(right, Const))
+ else if (is_funcclause((Node *) left) && IsA(right, Const))
{
List *vars = pull_var_clause((Node *) left);
@@ -662,52 +669,33 @@ get_relattval(Node *clause,
*constval = ((Const *) right)->constvalue;
*flag = (_SELEC_CONSTANT_RIGHT_ | _SELEC_IS_CONSTANT_);
}
- else if (is_opclause(clause) &&
- is_funcclause((Node *) right) &&
- IsA(left, Const))
+ else if (IsA(right, Var) && IsA(left, Const))
{
- List *vars = pull_var_clause((Node *) right);
-
- *relid = ((Var *) lfirst(vars))->varno;
- *attno = InvalidAttrNumber;
+ *relid = right->varno;
+ *attno = right->varattno;
*constval = ((Const *) left)->constvalue;
*flag = (_SELEC_IS_CONSTANT_);
-
- }
- else if (is_opclause(clause) && IsA(right, Var) &&
- IsA(left, Const))
- {
- if (left != NULL)
- {
-
- *relid = right->varno;
- *attno = right->varattno;
- *constval = ((Const *) left)->constvalue;
- *flag = (_SELEC_IS_CONSTANT_);
- }
- else
- {
-
- *relid = right->varno;
- *attno = right->varattno;
- *constval = 0;
- *flag = (_SELEC_NOT_CONSTANT_);
- }
}
- else if (is_opclause(clause) && IsA(right, Var) &&IsA(left, Param))
+ else if (IsA(right, Var) &&IsA(left, Param))
{
*relid = right->varno;
*attno = right->varattno;
*constval = 0;
*flag = (_SELEC_NOT_CONSTANT_);
}
- else
+ else if (is_funcclause((Node *) right) && IsA(left, Const))
{
+ List *vars = pull_var_clause((Node *) right);
- /*
- * One or more of the operands are expressions (e.g., oper
- * clauses)
- */
+ *relid = ((Var *) lfirst(vars))->varno;
+ *attno = InvalidAttrNumber;
+ *constval = ((Const *) left)->constvalue;
+ *flag = (_SELEC_IS_CONSTANT_);
+ }
+ else
+ {
+ /* Duh, it's too complicated for me... */
+default_results:
*relid = _SELEC_VALUE_UNKNOWN_;
*attno = _SELEC_VALUE_UNKNOWN_;
*constval = 0;
@@ -733,43 +721,47 @@ get_rels_atts(Node *clause,
int *relid2,
AttrNumber *attno2)
{
- Var *left = get_leftop((Expr *) clause);
- Var *right = get_rightop((Expr *) clause);
- bool var_left = (IsA(left, Var));
- bool var_right = (IsA(right, Var));
- bool varexpr_left = (bool) ((IsA(left, Func) ||IsA(left, Oper)) &&
- contain_var_clause((Node *) left));
- bool varexpr_right = (bool) ((IsA(right, Func) ||IsA(right, Oper)) &&
- contain_var_clause((Node *) right));
-
if (is_opclause(clause))
{
- if (var_left && var_right)
- {
+ Var *left = get_leftop((Expr *) clause);
+ Var *right = get_rightop((Expr *) clause);
- *relid1 = left->varno;
- *attno1 = left->varoattno;
- *relid2 = right->varno;
- *attno2 = right->varoattno;
- return;
- }
- else if (var_left && varexpr_right)
- {
-
- *relid1 = left->varno;
- *attno1 = left->varoattno;
- *relid2 = _SELEC_VALUE_UNKNOWN_;
- *attno2 = _SELEC_VALUE_UNKNOWN_;
- return;
- }
- else if (varexpr_left && var_right)
+ if (left && right)
{
+ bool var_left = IsA(left, Var);
+ bool var_right = IsA(right, Var);
+ bool varexpr_left = (bool) ((IsA(left, Func) || IsA(left, Oper)) &&
+ contain_var_clause((Node *) left));
+ bool varexpr_right = (bool) ((IsA(right, Func) || IsA(right, Oper)) &&
+ contain_var_clause((Node *) right));
- *relid1 = _SELEC_VALUE_UNKNOWN_;
- *attno1 = _SELEC_VALUE_UNKNOWN_;
- *relid2 = right->varno;
- *attno2 = right->varoattno;
- return;
+ if (var_left && var_right)
+ {
+
+ *relid1 = left->varno;
+ *attno1 = left->varoattno;
+ *relid2 = right->varno;
+ *attno2 = right->varoattno;
+ return;
+ }
+ if (var_left && varexpr_right)
+ {
+
+ *relid1 = left->varno;
+ *attno1 = left->varoattno;
+ *relid2 = _SELEC_VALUE_UNKNOWN_;
+ *attno2 = _SELEC_VALUE_UNKNOWN_;
+ return;
+ }
+ if (varexpr_left && var_right)
+ {
+
+ *relid1 = _SELEC_VALUE_UNKNOWN_;
+ *attno1 = _SELEC_VALUE_UNKNOWN_;
+ *relid2 = right->varno;
+ *attno2 = right->varoattno;
+ return;
+ }
}
}
@@ -777,7 +769,6 @@ get_rels_atts(Node *clause,
*attno1 = _SELEC_VALUE_UNKNOWN_;
*relid2 = _SELEC_VALUE_UNKNOWN_;
*attno2 = _SELEC_VALUE_UNKNOWN_;
- return;
}
void
@@ -813,4 +804,3 @@ CommuteClause(Node *clause)
lfirst(((Expr *) clause)->args) = lsecond(((Expr *) clause)->args);
lsecond(((Expr *) clause)->args) = temp;
}
-
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-31 13:44:35 +0000