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, 5 insertions, 3 deletions

diff --git a/src/backend/executor/nodeIndexscan.c b/src/backend/executor/nodeIndexscan.c
index 01c9de88f4d..d6012192a14 100644
--- a/src/backend/executor/nodeIndexscan.c
+++ b/src/backend/executor/nodeIndexscan.c
@@ -1227,7 +1227,9 @@ 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 */
@@ -1252,7 +1254,7 @@ 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");
 
 			/*
@@ -1375,7 +1377,7 @@ 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];
 
@@ -1499,7 +1501,7 @@ 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");
 
 			/*