Redesign DISTINCT ON as discussed in pgsql-sql 1/25/00: syntax is now

SELECT DISTINCT ON (expr [, expr ...]) targetlist ...
and there is a check to make sure that the user didn't specify an ORDER BY
that's incompatible with the DISTINCT operation.
Reimplement nodeUnique and nodeGroup to use the proper datatype-specific
equality function for each column being compared --- they used to do
bitwise comparisons or convert the data to text strings and strcmp().
(To add insult to injury, they'd look up the conversion functions once
for each tuple...)  Parse/plan representation of DISTINCT is now a list
of SortClause nodes.
initdb forced by querytree change...

1 files changed, 10 insertions, 10 deletions

diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c
index 358dba0a3ec..57169d9336e 100644
--- a/src/backend/rewrite/rewriteHandler.c
+++ b/src/backend/rewrite/rewriteHandler.c
@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.66 2000/01/26 05:56:49 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/rewrite/rewriteHandler.c,v 1.67 2000/01/27 18:11:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -536,8 +536,8 @@ modifyAggrefMakeSublink(Aggref *aggref, Query *parsetree)
 	subquery->isBinary = FALSE;
 	subquery->isTemp = FALSE;
 	subquery->unionall = FALSE;
-	subquery->uniqueFlag = NULL;
-	subquery->sortClause = NULL;
+	subquery->distinctClause = NIL;
+	subquery->sortClause = NIL;
 	subquery->rtable = lcons(copyObject(rte), NIL);
 	subquery->targetList = lcons(tle, NIL);
 	subquery->qual = modifyAggrefDropQual((Node *) parsetree->qual,
@@ -1725,7 +1725,7 @@ check_targetlists_are_compatible(List *prev_target, List *current_target)
  * The operator tree is attached to 'intersectClause' (see rule
  * 'SelectStmt' in gram.y) of the 'parsetree' given as an
  * argument. First we remember some clauses (the sortClause, the
- * unique flag etc.)  Then we translate the operator tree to DNF
+ * distinctClause etc.)  Then we translate the operator tree to DNF
  * (disjunctive normal form) by 'cnfify'. (Note that 'cnfify' produces
  * CNF but as we exchanged ANDs with ORs in function A_Expr_to_Expr()
  * earlier we get DNF after exchanging ANDs and ORs again in the
@@ -1736,8 +1736,8 @@ check_targetlists_are_compatible(List *prev_target, List *current_target)
  * union list is handed back but before that the remembered clauses
  * (sortClause etc) are attached to the new top Node (Note that the
  * new top Node can differ from the parsetree given as argument because of
- * the translation to DNF. That's why we have to remember the sortClause or
- * unique flag!) */
+ * the translation to DNF. That's why we have to remember the sortClause
+ * and so on!) */
 static Query *
 Except_Intersect_Rewrite(Query *parsetree)
 {
@@ -1750,12 +1750,12 @@ Except_Intersect_Rewrite(Query *parsetree)
 			   *intersect,
 			   *intersectClause;
 	List	   *union_list = NIL,
-			   *sortClause;
+			   *sortClause,
+			   *distinctClause;
 	List	   *left_expr,
 			   *right_expr,
 			   *resnames = NIL;
 	char	   *op,
-			   *uniqueFlag,
 			   *into;
 	bool		isBinary,
 				isPortal,
@@ -1806,7 +1806,7 @@ Except_Intersect_Rewrite(Query *parsetree)
 	 * node at the end of the function
 	 */
 	sortClause = parsetree->sortClause;
-	uniqueFlag = parsetree->uniqueFlag;
+	distinctClause = parsetree->distinctClause;
 	into = parsetree->into;
 	isBinary = parsetree->isBinary;
 	isPortal = parsetree->isPortal;
@@ -2009,7 +2009,7 @@ Except_Intersect_Rewrite(Query *parsetree)
 	result->unionClause = lnext(union_list);
 	/* Attach all the items remembered in the beginning of the function */
 	result->sortClause = sortClause;
-	result->uniqueFlag = uniqueFlag;
+	result->distinctClause = distinctClause;
 	result->into = into;
 	result->isPortal = isPortal;
 	result->isBinary = isBinary;