Relax ordering-related hardcoded btree requirements in planning

There were several places in ordering-related planning where a
requirement for btree was hardcoded but an amcanorder index could
suffice.  This fixes that.  We just need to do the necessary mapping
between strategy numbers and compare types and adjust some related
APIs so that this works independent of btree strategy numbers.  For
instance, non-btree amcanorder indexes can now be used to support
sorting and merge joins.  Also, predtest.c works independent of btree
strategy numbers now.

To avoid performance regressions, some details on btree and other
built-in index types are still hardcoded as shortcuts, but other index
types now have access to the same features by providing the required
flags and callbacks.

Author: Mark Dilger <mark.dilger@enterprisedb.com>
Co-authored-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://www.postgresql.org/message-id/flat/E72EAA49-354D-4C2E-8EB9-255197F55330@enterprisedb.com

2 files changed, 19 insertions, 19 deletions

diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c
index 2e64fcae7b2..9f20a70ce13 100644
--- a/src/backend/parser/parse_clause.c
+++ b/src/backend/parser/parse_clause.c
@@ -2915,7 +2915,7 @@ transformWindowDefinitions(ParseState *pstate,
 		{
 			SortGroupClause *sortcl;
 			Node	   *sortkey;
-			int16		rangestrategy;
+			CompareType rangecmptype;
 
 			if (list_length(wc->orderClause) != 1)
 				ereport(ERROR,
@@ -2928,7 +2928,7 @@ transformWindowDefinitions(ParseState *pstate,
 			if (!get_ordering_op_properties(sortcl->sortop,
 											&rangeopfamily,
 											&rangeopcintype,
-											&rangestrategy))
+											&rangecmptype))
 				elog(ERROR, "operator %u is not a valid ordering operator",
 					 sortcl->sortop);
 			/* Record properties of sort ordering */
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index bc602f00ae3..1f8e2d54673 100644
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -2832,7 +2832,7 @@ make_row_comparison_op(ParseState *pstate, List *opname,
 	ListCell   *l,
 			   *r;
 	List	  **opinfo_lists;
-	Bitmapset  *strats;
+	Bitmapset  *cmptypes;
 	int			nopers;
 	int			i;
 
@@ -2897,45 +2897,45 @@ make_row_comparison_op(ParseState *pstate, List *opname,
 
 	/*
 	 * Now we must determine which row comparison semantics (= <> < <= > >=)
-	 * apply to this set of operators.  We look for btree opfamilies
-	 * containing the operators, and see which interpretations (strategy
-	 * numbers) exist for each operator.
+	 * apply to this set of operators.  We look for opfamilies containing the
+	 * operators, and see which interpretations (cmptypes) exist for each
+	 * operator.
 	 */
 	opinfo_lists = (List **) palloc(nopers * sizeof(List *));
-	strats = NULL;
+	cmptypes = NULL;
 	i = 0;
 	foreach(l, opexprs)
 	{
 		Oid			opno = ((OpExpr *) lfirst(l))->opno;
-		Bitmapset  *this_strats;
+		Bitmapset  *this_cmptypes;
 		ListCell   *j;
 
-		opinfo_lists[i] = get_op_btree_interpretation(opno);
+		opinfo_lists[i] = get_op_index_interpretation(opno);
 
 		/*
-		 * convert strategy numbers into a Bitmapset to make the intersection
+		 * convert comparison types into a Bitmapset to make the intersection
 		 * calculation easy.
 		 */
-		this_strats = NULL;
+		this_cmptypes = NULL;
 		foreach(j, opinfo_lists[i])
 		{
-			OpBtreeInterpretation *opinfo = lfirst(j);
+			OpIndexInterpretation *opinfo = lfirst(j);
 
-			this_strats = bms_add_member(this_strats, opinfo->strategy);
+			this_cmptypes = bms_add_member(this_cmptypes, opinfo->cmptype);
 		}
 		if (i == 0)
-			strats = this_strats;
+			cmptypes = this_cmptypes;
 		else
-			strats = bms_int_members(strats, this_strats);
+			cmptypes = bms_int_members(cmptypes, this_cmptypes);
 		i++;
 	}
 
 	/*
 	 * If there are multiple common interpretations, we may use any one of
-	 * them ... this coding arbitrarily picks the lowest btree strategy
+	 * them ... this coding arbitrarily picks the lowest comparison type
 	 * number.
 	 */
-	i = bms_next_member(strats, -1);
+	i = bms_next_member(cmptypes, -1);
 	if (i < 0)
 	{
 		/* No common interpretation, so fail */
@@ -2969,9 +2969,9 @@ make_row_comparison_op(ParseState *pstate, List *opname,
 
 		foreach(j, opinfo_lists[i])
 		{
-			OpBtreeInterpretation *opinfo = lfirst(j);
+			OpIndexInterpretation *opinfo = lfirst(j);
 
-			if (opinfo->strategy == cmptype)
+			if (opinfo->cmptype == cmptype)
 			{
 				opfamily = opinfo->opfamily_id;
 				break;