From 8224de4f42ccf98e08db07b43d52fed72f962ebb Mon Sep 17 00:00:00 2001
From: Teodor Sigaev
Date: Sat, 7 Apr 2018 23:00:39 +0300
Subject: 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
---
 src/include/utils/rel.h | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

(limited to 'src/include/utils/rel.h')

diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 9826c67fc41..ffffde01da9 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -438,10 +438,24 @@ typedef struct ViewOptions
 
 /*
  * RelationGetNumberOfAttributes
- *		Returns the number of attributes in a relation.
+ *		Returns the total number of attributes in a relation.
  */
 #define RelationGetNumberOfAttributes(relation) ((relation)->rd_rel->relnatts)
 
+/*
+ * IndexRelationGetNumberOfAttributes
+ *		Returns the number of attributes in an index.
+ */
+#define IndexRelationGetNumberOfAttributes(relation) \
+		((relation)->rd_index->indnatts)
+
+/*
+ * IndexRelationGetNumberOfKeyAttributes
+ *		Returns the number of key attributes in an index.
+ */
+#define IndexRelationGetNumberOfKeyAttributes(relation) \
+		((relation)->rd_index->indnkeyatts)
+
 /*
  * RelationGetDescr
  *		Returns tuple descriptor for a relation.
-- 
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