CREATE INDEX ... INCLUDING (column[, ...])

Now indexes (but only B-tree for now) can contain "extra" column(s) which
doesn't participate in index structure, they are just stored in leaf
tuples. It allows to use index only scan by using single index instead
of two or more indexes.

Author: Anastasia Lubennikova with minor editorializing by me
Reviewers: David Rowley, Peter Geoghegan, Jeff Janes

2 files changed, 12 insertions, 10 deletions

diff --git a/src/backend/executor/execIndexing.c b/src/backend/executor/execIndexing.c
index 5d553d51d21..ecd2723f0b6 100644
--- a/src/backend/executor/execIndexing.c
+++ b/src/backend/executor/execIndexing.c
@@ -646,7 +646,7 @@ check_exclusion_or_unique_constraint(Relation heap, Relation index,
 	Oid		   *constr_procs;
 	uint16	   *constr_strats;
 	Oid		   *index_collations = index->rd_indcollation;
-	int			index_natts = index->rd_index->indnatts;
+	int			indnkeyatts = IndexRelationGetNumberOfKeyAttributes(index);
 	IndexScanDesc index_scan;
 	HeapTuple	tup;
 	ScanKeyData scankeys[INDEX_MAX_KEYS];
@@ -673,7 +673,7 @@ check_exclusion_or_unique_constraint(Relation heap, Relation index,
 	 * If any of the input values are NULL, the constraint check is assumed to
 	 * pass (i.e., we assume the operators are strict).
 	 */
-	for (i = 0; i < index_natts; i++)
+	for (i = 0; i < indnkeyatts; i++)
 	{
 		if (isnull[i])
 			return true;
@@ -685,7 +685,7 @@ check_exclusion_or_unique_constraint(Relation heap, Relation index,
 	 */
 	InitDirtySnapshot(DirtySnapshot);
 
-	for (i = 0; i < index_natts; i++)
+	for (i = 0; i < indnkeyatts; i++)
 	{
 		ScanKeyEntryInitialize(&scankeys[i],
 							   0,
@@ -717,8 +717,8 @@ check_exclusion_or_unique_constraint(Relation heap, Relation index,
 retry:
 	conflict = false;
 	found_self = false;
-	index_scan = index_beginscan(heap, index, &DirtySnapshot, index_natts, 0);
-	index_rescan(index_scan, scankeys, index_natts, NULL, 0);
+	index_scan = index_beginscan(heap, index, &DirtySnapshot, indnkeyatts, 0);
+	index_rescan(index_scan, scankeys, indnkeyatts, NULL, 0);
 
 	while ((tup = index_getnext(index_scan,
 								ForwardScanDirection)) != NULL)
@@ -879,10 +879,10 @@ index_recheck_constraint(Relation index, Oid *constr_procs,
 						 Datum *existing_values, bool *existing_isnull,
 						 Datum *new_values)
 {
-	int			index_natts = index->rd_index->indnatts;
+	int			indnkeyatts = IndexRelationGetNumberOfKeyAttributes(index);
 	int			i;
 
-	for (i = 0; i < index_natts; i++)
+	for (i = 0; i < indnkeyatts; i++)
 	{
 		/* Assume the exclusion operators are strict */
 		if (existing_isnull[i])
diff --git a/src/backend/executor/nodeIndexscan.c b/src/backend/executor/nodeIndexscan.c
index bf16cb1b57e..69e82cbe7a5 100644
--- a/src/backend/executor/nodeIndexscan.c
+++ b/src/backend/executor/nodeIndexscan.c
@@ -1144,7 +1144,9 @@ ExecIndexBuildScanKeys(PlanState *planstate, Relation index,
 		Expr	   *leftop;		/* expr on lhs of operator */
 		Expr	   *rightop;	/* expr on rhs ... */
 		AttrNumber	varattno;	/* att number used in scan */
+		int			indnkeyatts;
 
+		indnkeyatts = IndexRelationGetNumberOfKeyAttributes(index);
 		if (IsA(clause, OpExpr))
 		{
 			/* indexkey op const or indexkey op expression */
@@ -1169,7 +1171,7 @@ ExecIndexBuildScanKeys(PlanState *planstate, Relation index,
 				elog(ERROR, "indexqual doesn't have key on left side");
 
 			varattno = ((Var *) leftop)->varattno;
-			if (varattno < 1 || varattno > index->rd_index->indnatts)
+			if (varattno < 1 || varattno > indnkeyatts)
 				elog(ERROR, "bogus index qualification");
 
 			/*
@@ -1292,7 +1294,7 @@ ExecIndexBuildScanKeys(PlanState *planstate, Relation index,
 				opnos_cell = lnext(opnos_cell);
 
 				if (index->rd_rel->relam != BTREE_AM_OID ||
-					varattno < 1 || varattno > index->rd_index->indnatts)
+					varattno < 1 || varattno > indnkeyatts)
 					elog(ERROR, "bogus RowCompare index qualification");
 				opfamily = index->rd_opfamily[varattno - 1];
 
@@ -1413,7 +1415,7 @@ ExecIndexBuildScanKeys(PlanState *planstate, Relation index,
 				elog(ERROR, "indexqual doesn't have key on left side");
 
 			varattno = ((Var *) leftop)->varattno;
-			if (varattno < 1 || varattno > index->rd_index->indnatts)
+			if (varattno < 1 || varattno > indnkeyatts)
 				elog(ERROR, "bogus index qualification");
 
 			/*