Indexes with INCLUDE columns and their support in B-tree

This patch introduces INCLUDE clause to index definition.  This clause
specifies a list of columns which will be included as a non-key part in
the index.  The INCLUDE columns exist solely to allow more queries to
benefit from index-only scans.  Also, such columns don't need to have
appropriate operator classes.  Expressions are not supported as INCLUDE
columns since they cannot be used in index-only scans.

Index access methods supporting INCLUDE are indicated by amcaninclude flag
in IndexAmRoutine.  For now, only B-tree indexes support INCLUDE clause.

In B-tree indexes INCLUDE columns are truncated from pivot index tuples
(tuples located in non-leaf pages and high keys).  Therefore, B-tree indexes
now might have variable number of attributes.  This patch also provides
generic facility to support that: pivot tuples contain number of their
attributes in t_tid.ip_posid.  Free 13th bit of t_info is used for indicating
that.  This facility will simplify further support of index suffix truncation.
The changes of above are backward-compatible, pg_upgrade doesn't need special
handling of B-tree indexes for that.

Bump catalog version

Author: Anastasia Lubennikova with contribition by Alexander Korotkov and me
Reviewed by: Peter Geoghegan, Tomas Vondra, Antonin Houska, Jeff Janes,
			 David Rowley, Alexander Korotkov
Discussion: https://www.postgresql.org/message-id/flat/56168952.4010101@postgrespro.ru

1 files changed, 1 insertions, 3 deletions

diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 0bafb4fefcd..201d1f5a1b4 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8023,7 +8023,6 @@ ExtractReplicaIdentity(Relation relation, HeapTuple tp, bool key_changed, bool *
 	TupleDesc	desc = RelationGetDescr(relation);
 	Oid			replidindex;
 	Relation	idx_rel;
-	TupleDesc	idx_desc;
 	char		replident = relation->rd_rel->relreplident;
 	HeapTuple	key_tuple = NULL;
 	bool		nulls[MaxHeapAttributeNumber];
@@ -8066,7 +8065,6 @@ ExtractReplicaIdentity(Relation relation, HeapTuple tp, bool key_changed, bool *
 	}
 
 	idx_rel = RelationIdGetRelation(replidindex);
-	idx_desc = RelationGetDescr(idx_rel);
 
 	/* deform tuple, so we have fast access to columns */
 	heap_deform_tuple(tp, desc, values, nulls);
@@ -8078,7 +8076,7 @@ ExtractReplicaIdentity(Relation relation, HeapTuple tp, bool key_changed, bool *
 	 * Now set all columns contained in the index to NOT NULL, they cannot
 	 * currently be NULL.
 	 */
-	for (natt = 0; natt < idx_desc->natts; natt++)
+	for (natt = 0; natt < IndexRelationGetNumberOfKeyAttributes(idx_rel); natt++)
 	{
 		int			attno = idx_rel->rd_index->indkey.values[natt];