Restructure SPGiST opclass interface API to support whole-index scans.

The original API definition was incapable of supporting whole-index scans
because there was no way to invoke leaf-value reconstruction without
checking any qual conditions.  Also, it was inefficient for
multiple-qual-condition scans because value reconstruction got done over
again for each qual condition, and because other internal work in the
consistent functions likewise had to be done for each qual.  To fix these
issues, pass the whole scankey array to the opclass consistent functions,
instead of only letting them see one item at a time.  (Essentially, the
loop over scankey entries is now inside the consistent functions not
outside them.  This makes the consistent functions a bit more complicated,
but not unreasonably so.)

In itself this commit does nothing except save a few cycles in
multiple-qual-condition index scans, since we can't support whole-index
scans on SPGiST indexes until nulls are included in the index.  However,
I consider this a must-fix for 9.2 because once we release it will get
very much harder to change the opclass API definition.

1 files changed, 118 insertions, 122 deletions

diff --git a/src/backend/access/spgist/spgquadtreeproc.c b/src/backend/access/spgist/spgquadtreeproc.c
index 231749e992d..10fafe58643 100644
--- a/src/backend/access/spgist/spgquadtreeproc.c
+++ b/src/backend/access/spgist/spgquadtreeproc.c
@@ -190,45 +190,21 @@ spg_quad_picksplit(PG_FUNCTION_ARGS)
 }
 
 
-/* Subroutine to fill out->nodeNumbers[] for spg_quad_inner_consistent */
-static void
-setNodes(spgInnerConsistentOut *out, bool isAll, int first, int second)
-{
-	if (isAll)
-	{
-		out->nNodes = 4;
-		out->nodeNumbers[0] = 0;
-		out->nodeNumbers[1] = 1;
-		out->nodeNumbers[2] = 2;
-		out->nodeNumbers[3] = 3;
-	}
-	else
-	{
-		out->nNodes = 2;
-		out->nodeNumbers[0] = first - 1;
-		out->nodeNumbers[1] = second - 1;
-	}
-}
-
-
 Datum
 spg_quad_inner_consistent(PG_FUNCTION_ARGS)
 {
 	spgInnerConsistentIn *in = (spgInnerConsistentIn *) PG_GETARG_POINTER(0);
 	spgInnerConsistentOut *out = (spgInnerConsistentOut *) PG_GETARG_POINTER(1);
-	Point	   *query,
-			   *centroid;
-	BOX		   *boxQuery;
+	Point	   *centroid;
+	int			which;
+	int			i;
 
-	query = DatumGetPointP(in->query);
 	Assert(in->hasPrefix);
 	centroid = DatumGetPointP(in->prefixDatum);
 
 	if (in->allTheSame)
 	{
 		/* Report that all nodes should be visited */
-		int		i;
-
 		out->nNodes = in->nNodes;
 		out->nodeNumbers = (int *) palloc(sizeof(int) * in->nNodes);
 		for (i = 0; i < in->nNodes; i++)
@@ -237,76 +213,86 @@ spg_quad_inner_consistent(PG_FUNCTION_ARGS)
 	}
 
 	Assert(in->nNodes == 4);
-	out->nodeNumbers = (int *) palloc(sizeof(int) * 4);
 
-	switch (in->strategy)
+	/* "which" is a bitmask of quadrants that satisfy all constraints */
+	which = (1 << 1) | (1 << 2) | (1 << 3) | (1 << 4);
+
+	for (i = 0; i < in->nkeys; i++)
 	{
-		case RTLeftStrategyNumber:
-			setNodes(out, SPTEST(point_left, centroid, query), 3, 4);
-			break;
-		case RTRightStrategyNumber:
-			setNodes(out, SPTEST(point_right, centroid, query), 1, 2);
-			break;
-		case RTSameStrategyNumber:
-			out->nNodes = 1;
-			out->nodeNumbers[0] = getQuadrant(centroid, query) - 1;
-			break;
-		case RTBelowStrategyNumber:
-			setNodes(out, SPTEST(point_below, centroid, query), 2, 3);
-			break;
-		case RTAboveStrategyNumber:
-			setNodes(out, SPTEST(point_above, centroid, query), 1, 4);
-			break;
-		case RTContainedByStrategyNumber:
-
-			/*
-			 * For this operator, the query is a box not a point.  We cheat to
-			 * the extent of assuming that DatumGetPointP won't do anything
-			 * that would be bad for a pointer-to-box.
-			 */
-			boxQuery = DatumGetBoxP(in->query);
-
-			if (DatumGetBool(DirectFunctionCall2(box_contain_pt,
-												 PointerGetDatum(boxQuery),
-												 PointerGetDatum(centroid))))
-			{
-				/* centroid is in box, so descend to all quadrants */
-				setNodes(out, true, 0, 0);
-			}
-			else
-			{
-				/* identify quadrant(s) containing all corners of box */
-				Point		p;
-				int			i,
-							r = 0;
-
-				p = boxQuery->low;
-				r |= 1 << (getQuadrant(centroid, &p) - 1);
-
-				p.y = boxQuery->high.y;
-				r |= 1 << (getQuadrant(centroid, &p) - 1);
-
-				p = boxQuery->high;
-				r |= 1 << (getQuadrant(centroid, &p) - 1);
-
-				p.x = boxQuery->low.x;
-				r |= 1 << (getQuadrant(centroid, &p) - 1);
-
-				/* we must descend into those quadrant(s) */
-				out->nNodes = 0;
-				for (i = 0; i < 4; i++)
+		Point	   *query = DatumGetPointP(in->scankeys[i].sk_argument);
+		BOX		   *boxQuery;
+
+		switch (in->scankeys[i].sk_strategy)
+		{
+			case RTLeftStrategyNumber:
+				if (SPTEST(point_right, centroid, query))
+					which &= (1 << 3) | (1 << 4);
+				break;
+			case RTRightStrategyNumber:
+				if (SPTEST(point_left, centroid, query))
+					which &= (1 << 1) | (1 << 2);
+				break;
+			case RTSameStrategyNumber:
+				which &= (1 << getQuadrant(centroid, query));
+				break;
+			case RTBelowStrategyNumber:
+				if (SPTEST(point_above, centroid, query))
+					which &= (1 << 2) | (1 << 3);
+				break;
+			case RTAboveStrategyNumber:
+				if (SPTEST(point_below, centroid, query))
+					which &= (1 << 1) | (1 << 4);
+				break;
+			case RTContainedByStrategyNumber:
+
+				/*
+				 * For this operator, the query is a box not a point.  We
+				 * cheat to the extent of assuming that DatumGetPointP won't
+				 * do anything that would be bad for a pointer-to-box.
+				 */
+				boxQuery = DatumGetBoxP(in->scankeys[i].sk_argument);
+
+				if (DatumGetBool(DirectFunctionCall2(box_contain_pt,
+													 PointerGetDatum(boxQuery),
+													 PointerGetDatum(centroid))))
 				{
-					if (r & (1 << i))
-					{
-						out->nodeNumbers[out->nNodes] = i;
-						out->nNodes++;
-					}
+					/* centroid is in box, so all quadrants are OK */
 				}
-			}
-			break;
-		default:
-			elog(ERROR, "unrecognized strategy number: %d", in->strategy);
-			break;
+				else
+				{
+					/* identify quadrant(s) containing all corners of box */
+					Point		p;
+					int			r = 0;
+
+					p = boxQuery->low;
+					r |= 1 << getQuadrant(centroid, &p);
+					p.y = boxQuery->high.y;
+					r |= 1 << getQuadrant(centroid, &p);
+					p = boxQuery->high;
+					r |= 1 << getQuadrant(centroid, &p);
+					p.x = boxQuery->low.x;
+					r |= 1 << getQuadrant(centroid, &p);
+
+					which &= r;
+				}
+				break;
+			default:
+				elog(ERROR, "unrecognized strategy number: %d",
+					 in->scankeys[i].sk_strategy);
+				break;
+		}
+
+		if (which == 0)
+			break;				/* no need to consider remaining conditions */
+	}
+
+	/* We must descend into the quadrant(s) identified by which */
+	out->nodeNumbers = (int *) palloc(sizeof(int) * 4);
+	out->nNodes = 0;
+	for (i = 1; i <= 4; i++)
+	{
+		if (which & (1 << i))
+			out->nodeNumbers[out->nNodes++] = i - 1;
 	}
 
 	PG_RETURN_VOID();
@@ -318,9 +304,9 @@ spg_quad_leaf_consistent(PG_FUNCTION_ARGS)
 {
 	spgLeafConsistentIn *in = (spgLeafConsistentIn *) PG_GETARG_POINTER(0);
 	spgLeafConsistentOut *out = (spgLeafConsistentOut *) PG_GETARG_POINTER(1);
-	Point	   *query = DatumGetPointP(in->query);
 	Point	   *datum = DatumGetPointP(in->leafDatum);
 	bool		res;
+	int			i;
 
 	/* all tests are exact */
 	out->recheck = false;
@@ -328,35 +314,45 @@ spg_quad_leaf_consistent(PG_FUNCTION_ARGS)
 	/* leafDatum is what it is... */
 	out->leafValue = in->leafDatum;
 
-	switch (in->strategy)
+	/* Perform the required comparison(s) */
+	res = true;
+	for (i = 0; i < in->nkeys; i++)
 	{
-		case RTLeftStrategyNumber:
-			res = SPTEST(point_left, datum, query);
-			break;
-		case RTRightStrategyNumber:
-			res = SPTEST(point_right, datum, query);
-			break;
-		case RTSameStrategyNumber:
-			res = SPTEST(point_eq, datum, query);
-			break;
-		case RTBelowStrategyNumber:
-			res = SPTEST(point_below, datum, query);
-			break;
-		case RTAboveStrategyNumber:
-			res = SPTEST(point_above, datum, query);
-			break;
-		case RTContainedByStrategyNumber:
-
-			/*
-			 * For this operator, the query is a box not a point.  We cheat to
-			 * the extent of assuming that DatumGetPointP won't do anything
-			 * that would be bad for a pointer-to-box.
-			 */
-			res = SPTEST(box_contain_pt, query, datum);
-			break;
-		default:
-			elog(ERROR, "unrecognized strategy number: %d", in->strategy);
-			res = false;
+		Point	   *query = DatumGetPointP(in->scankeys[i].sk_argument);
+
+		switch (in->scankeys[i].sk_strategy)
+		{
+			case RTLeftStrategyNumber:
+				res = SPTEST(point_left, datum, query);
+				break;
+			case RTRightStrategyNumber:
+				res = SPTEST(point_right, datum, query);
+				break;
+			case RTSameStrategyNumber:
+				res = SPTEST(point_eq, datum, query);
+				break;
+			case RTBelowStrategyNumber:
+				res = SPTEST(point_below, datum, query);
+				break;
+			case RTAboveStrategyNumber:
+				res = SPTEST(point_above, datum, query);
+				break;
+			case RTContainedByStrategyNumber:
+
+				/*
+				 * For this operator, the query is a box not a point.  We
+				 * cheat to the extent of assuming that DatumGetPointP won't
+				 * do anything that would be bad for a pointer-to-box.
+				 */
+				res = SPTEST(box_contain_pt, query, datum);
+				break;
+			default:
+				elog(ERROR, "unrecognized strategy number: %d",
+					 in->scankeys[i].sk_strategy);
+				break;
+		}
+
+		if (!res)
 			break;
 	}