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

3 files changed, 18 insertions, 9 deletions

diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index dbec07e5a37..e5df6da6585 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -33,9 +33,11 @@
  *		entries for a particular index.  Used for both index_build and
  *		retail creation of index entries.
  *
- *		NumIndexAttrs		number of columns in this index
+ *		NumIndexAttrs		total number of columns in this index
+ *		NumIndexKeyAttrs	number of key columns in index
  *		KeyAttrNumbers		underlying-rel attribute numbers used as keys
- *							(zeroes indicate expressions)
+ *							(zeroes indicate expressions). It also contains
+ * 							info about included columns.
  *		Expressions			expr trees for expression entries, or NIL if none
  *		ExpressionsState	exec state for expressions, or NIL if none
  *		Predicate			partial-index predicate, or NIL if none
@@ -58,7 +60,8 @@
 typedef struct IndexInfo
 {
 	NodeTag		type;
-	int			ii_NumIndexAttrs;
+	int			ii_NumIndexAttrs; /* total number of columns in index */
+	int			ii_NumIndexKeyAttrs; /* number of key columns in index */
 	AttrNumber	ii_KeyAttrNumbers[INDEX_MAX_KEYS];
 	List	   *ii_Expressions; /* list of Expr */
 	List	   *ii_ExpressionsState;	/* list of ExprState */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 714cf1550fd..7038ebb804a 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1835,7 +1835,8 @@ typedef struct Constraint
 	char	   *cooked_expr;	/* expr, as nodeToString representation */
 
 	/* Fields used for unique constraints (UNIQUE and PRIMARY KEY): */
-	List	   *keys;			/* String nodes naming referenced column(s) */
+	List	   *keys;			/* String nodes naming referenced key column(s) */
+	List	   *including;		/* String nodes naming referenced nonkey column(s) */
 
 	/* Fields used for EXCLUSION constraints: */
 	List	   *exclusions;		/* list of (IndexElem, operator name) pairs */
@@ -2439,6 +2440,8 @@ typedef struct IndexStmt
 	char	   *accessMethod;	/* name of access method (eg. btree) */
 	char	   *tableSpace;		/* tablespace, or NULL for default */
 	List	   *indexParams;	/* columns to index: a list of IndexElem */
+	List	   *indexIncludingParams;	/* additional columns to index:
+										 * a list of IndexElem */
 	List	   *options;		/* WITH clause options: a list of DefElem */
 	Node	   *whereClause;	/* qualification (partial-index predicate) */
 	List	   *excludeOpNames; /* exclusion operator names, or NIL if none */
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index e9dfb663c20..9bfeedaf571 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -545,11 +545,12 @@ typedef struct RelOptInfo
  * IndexOptInfo
  *		Per-index information for planning/optimization
  *
- *		indexkeys[], indexcollations[], opfamily[], and opcintype[]
- *		each have ncolumns entries.
+ *		indexkeys[], indexcollations[] each have ncolumns entries.
+ *		opfamily[], and opcintype[]	each have nkeycolumns entries. They do
+ *		not contain any information about included attributes.
  *
- *		sortopfamily[], reverse_sort[], and nulls_first[] likewise have
- *		ncolumns entries, if the index is ordered; but if it is unordered,
+ *		sortopfamily[], reverse_sort[], and nulls_first[] have
+ *		nkeycolumns entries, if the index is ordered; but if it is unordered,
  *		those pointers are NULL.
  *
  *		Zeroes in the indexkeys[] array indicate index columns that are
@@ -586,7 +587,9 @@ typedef struct IndexOptInfo
 
 	/* index descriptor information */
 	int			ncolumns;		/* number of columns in index */
-	int		   *indexkeys;		/* column numbers of index's keys, or 0 */
+	int			nkeycolumns;	/* number of key columns in index */
+	int		   *indexkeys;		/* column numbers of index's attributes
+								 * both key and included columns, or 0 */
 	Oid		   *indexcollations;	/* OIDs of collations of index columns */
 	Oid		   *opfamily;		/* OIDs of operator families for columns */
 	Oid		   *opcintype;		/* OIDs of opclass declared input data types */