Add support for MERGE SQL command

MERGE performs actions that modify rows in the target table using a
source table or query. MERGE provides a single SQL statement that can
conditionally INSERT/UPDATE/DELETE rows -- a task that would otherwise
require multiple PL statements.  For example,

MERGE INTO target AS t
USING source AS s
ON t.tid = s.sid
WHEN MATCHED AND t.balance > s.delta THEN
  UPDATE SET balance = t.balance - s.delta
WHEN MATCHED THEN
  DELETE
WHEN NOT MATCHED AND s.delta > 0 THEN
  INSERT VALUES (s.sid, s.delta)
WHEN NOT MATCHED THEN
  DO NOTHING;

MERGE works with regular tables, partitioned tables and inheritance
hierarchies, including column and row security enforcement, as well as
support for row and statement triggers and transition tables therein.

MERGE is optimized for OLTP and is parameterizable, though also useful
for large scale ETL/ELT. MERGE is not intended to be used in preference
to existing single SQL commands for INSERT, UPDATE or DELETE since there
is some overhead.  MERGE can be used from PL/pgSQL.

MERGE does not support targetting updatable views or foreign tables, and
RETURNING clauses are not allowed either.  These limitations are likely
fixable with sufficient effort.  Rewrite rules are also not supported,
but it's not clear that we'd want to support them.

Author: Pavan Deolasee <pavan.deolasee@gmail.com>
Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Author: Amit Langote <amitlangote09@gmail.com>
Author: Simon Riggs <simon.riggs@enterprisedb.com>
Reviewed-by: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Reviewed-by: Andres Freund <andres@anarazel.de> (earlier versions)
Reviewed-by: Peter Geoghegan <pg@bowt.ie> (earlier versions)
Reviewed-by: Robert Haas <robertmhaas@gmail.com> (earlier versions)
Reviewed-by: Japin Li <japinli@hotmail.com>
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com>
Reviewed-by: Zhihong Yu <zyu@yugabyte.com>
Discussion: https://postgr.es/m/CANP8+jKitBSrB7oTgT9CY2i1ObfOt36z0XMraQc+Xrz8QB0nXA@mail.gmail.com
Discussion: https://postgr.es/m/CAH2-WzkJdBuxj9PO=2QaO9-3h3xGbQPZ34kJH=HukRekwM-GZg@mail.gmail.com
Discussion: https://postgr.es/m/20201231134736.GA25392@alvherre.pgsql

16 files changed, 150 insertions, 15 deletions

diff --git a/src/include/commands/trigger.h b/src/include/commands/trigger.h
index 66bf6c16e34..194e8d5bc13 100644
--- a/src/include/commands/trigger.h
+++ b/src/include/commands/trigger.h
@@ -13,6 +13,7 @@
 #ifndef TRIGGER_H
 #define TRIGGER_H
 
+#include "access/tableam.h"
 #include "catalog/objectaddress.h"
 #include "nodes/execnodes.h"
 #include "nodes/parsenodes.h"
@@ -229,7 +230,8 @@ extern bool ExecBRUpdateTriggers(EState *estate,
 								 ResultRelInfo *relinfo,
 								 ItemPointer tupleid,
 								 HeapTuple fdw_trigtuple,
-								 TupleTableSlot *slot);
+								 TupleTableSlot *slot,
+								 TM_FailureData *tmfdp);
 extern void ExecARUpdateTriggers(EState *estate,
 								 ResultRelInfo *relinfo,
 								 ResultRelInfo *src_partinfo,
diff --git a/src/include/executor/nodeModifyTable.h b/src/include/executor/nodeModifyTable.h
index 1d225bc88d5..c318681b9ae 100644
--- a/src/include/executor/nodeModifyTable.h
+++ b/src/include/executor/nodeModifyTable.h
@@ -23,4 +23,7 @@ extern ModifyTableState *ExecInitModifyTable(ModifyTable *node, EState *estate,
 extern void ExecEndModifyTable(ModifyTableState *node);
 extern void ExecReScanModifyTable(ModifyTableState *node);
 
+extern void ExecInitMergeTupleSlots(ModifyTableState *mtstate,
+									ResultRelInfo *resultRelInfo);
+
 #endif							/* NODEMODIFYTABLE_H */
diff --git a/src/include/executor/spi.h b/src/include/executor/spi.h
index 6ec38514445..b2c0c7486ce 100644
--- a/src/include/executor/spi.h
+++ b/src/include/executor/spi.h
@@ -96,6 +96,7 @@ typedef struct _SPI_plan *SPIPlanPtr;
 #define SPI_OK_REL_REGISTER		15
 #define SPI_OK_REL_UNREGISTER	16
 #define SPI_OK_TD_REGISTER		17
+#define SPI_OK_MERGE			18
 
 #define SPI_OPT_NONATOMIC		(1 << 0)
 
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 44dd73fc80e..cbbcff81d2e 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -389,6 +389,22 @@ typedef struct OnConflictSetState
 	ExprState  *oc_WhereClause; /* state for the WHERE clause */
 } OnConflictSetState;
 
+/* ----------------
+ *	 MergeActionState information
+ *
+ *	Executor state for a MERGE action.
+ * ----------------
+ */
+typedef struct MergeActionState
+{
+	NodeTag		type;
+
+	MergeAction *mas_action;	/* associated MergeAction node */
+	ProjectionInfo *mas_proj;	/* projection of the action's targetlist for
+								 * this rel */
+	ExprState  *mas_whenqual;	/* WHEN [NOT] MATCHED AND conditions */
+} MergeActionState;
+
 /*
  * ResultRelInfo
  *
@@ -500,6 +516,10 @@ typedef struct ResultRelInfo
 	/* ON CONFLICT evaluation state */
 	OnConflictSetState *ri_onConflict;
 
+	/* for MERGE, lists of MergeActionState */
+	List	   *ri_matchedMergeAction;
+	List	   *ri_notMatchedMergeAction;
+
 	/* partition check expression state (NULL if not set up yet) */
 	ExprState  *ri_PartitionCheckExpr;
 
@@ -1190,6 +1210,12 @@ typedef struct ProjectSetState
 	MemoryContext argcontext;	/* context for SRF arguments */
 } ProjectSetState;
 
+
+/* flags for mt_merge_subcommands */
+#define MERGE_INSERT	0x01
+#define MERGE_UPDATE	0x02
+#define MERGE_DELETE	0x04
+
 /* ----------------
  *	 ModifyTableState information
  * ----------------
@@ -1197,7 +1223,7 @@ typedef struct ProjectSetState
 typedef struct ModifyTableState
 {
 	PlanState	ps;				/* its first field is NodeTag */
-	CmdType		operation;		/* INSERT, UPDATE, or DELETE */
+	CmdType		operation;		/* INSERT, UPDATE, DELETE, or MERGE */
 	bool		canSetTag;		/* do we set the command tag/es_processed? */
 	bool		mt_done;		/* are we done? */
 	int			mt_nrels;		/* number of entries in resultRelInfo[] */
@@ -1239,6 +1265,14 @@ typedef struct ModifyTableState
 
 	/* controls transition table population for INSERT...ON CONFLICT UPDATE */
 	struct TransitionCaptureState *mt_oc_transition_capture;
+
+	/* Flags showing which subcommands are present INS/UPD/DEL/DO NOTHING */
+	int			mt_merge_subcommands;
+
+	/* tuple counters for MERGE */
+	double		mt_merge_inserted;
+	double		mt_merge_updated;
+	double		mt_merge_deleted;
 } ModifyTableState;
 
 /* ----------------
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index 05f0b79e82e..ca440eb75ff 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -35,6 +35,7 @@ typedef enum NodeTag
 	T_ProjectionInfo,
 	T_JunkFilter,
 	T_OnConflictSetState,
+	T_MergeActionState,
 	T_ResultRelInfo,
 	T_EState,
 	T_TupleTableSlot,
@@ -283,6 +284,7 @@ typedef enum NodeTag
 	T_RollupData,
 	T_GroupingSetData,
 	T_StatisticExtInfo,
+	T_MergeAction,
 
 	/*
 	 * TAGS FOR MEMORY NODES (memnodes.h)
@@ -321,6 +323,7 @@ typedef enum NodeTag
 	T_InsertStmt,
 	T_DeleteStmt,
 	T_UpdateStmt,
+	T_MergeStmt,
 	T_SelectStmt,
 	T_ReturnStmt,
 	T_PLAssignStmt,
@@ -485,6 +488,7 @@ typedef enum NodeTag
 	T_CTESearchClause,
 	T_CTECycleClause,
 	T_CommonTableExpr,
+	T_MergeWhenClause,
 	T_RoleSpec,
 	T_TriggerTransition,
 	T_PartitionElem,
@@ -698,7 +702,8 @@ typedef enum CmdType
 	CMD_SELECT,					/* select stmt */
 	CMD_UPDATE,					/* update stmt */
 	CMD_INSERT,					/* insert stmt */
-	CMD_DELETE,
+	CMD_DELETE,					/* delete stmt */
+	CMD_MERGE,					/* merge stmt */
 	CMD_UTILITY,				/* cmds like create, destroy, copy, vacuum,
 								 * etc. */
 	CMD_NOTHING					/* dummy command for instead nothing rules
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 3b12a708ec0..6bf212b01a1 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -119,7 +119,7 @@ typedef struct Query
 {
 	NodeTag		type;
 
-	CmdType		commandType;	/* select|insert|update|delete|utility */
+	CmdType		commandType;	/* select|insert|update|delete|merge|utility */
 
 	QuerySource querySource;	/* where did I come from? */
 
@@ -130,7 +130,7 @@ typedef struct Query
 	Node	   *utilityStmt;	/* non-null if commandType == CMD_UTILITY */
 
 	int			resultRelation; /* rtable index of target relation for
-								 * INSERT/UPDATE/DELETE; 0 for SELECT */
+								 * INSERT/UPDATE/DELETE/MERGE; 0 for SELECT */
 
 	bool		hasAggs;		/* has aggregates in tlist or havingQual */
 	bool		hasWindowFuncs; /* has window functions in tlist */
@@ -147,7 +147,11 @@ typedef struct Query
 	List	   *cteList;		/* WITH list (of CommonTableExpr's) */
 
 	List	   *rtable;			/* list of range table entries */
-	FromExpr   *jointree;		/* table join tree (FROM and WHERE clauses) */
+	FromExpr   *jointree;		/* table join tree (FROM and WHERE clauses);
+								 * also USING clause for MERGE */
+
+	List	   *mergeActionList;	/* list of actions for MERGE (only) */
+	bool		mergeUseOuterJoin;	/* whether to use outer join */
 
 	List	   *targetList;		/* target list (of TargetEntry) */
 
@@ -1221,7 +1225,9 @@ typedef enum WCOKind
 	WCO_VIEW_CHECK,				/* WCO on an auto-updatable view */
 	WCO_RLS_INSERT_CHECK,		/* RLS INSERT WITH CHECK policy */
 	WCO_RLS_UPDATE_CHECK,		/* RLS UPDATE WITH CHECK policy */
-	WCO_RLS_CONFLICT_CHECK		/* RLS ON CONFLICT DO UPDATE USING policy */
+	WCO_RLS_CONFLICT_CHECK,		/* RLS ON CONFLICT DO UPDATE USING policy */
+	WCO_RLS_MERGE_UPDATE_CHECK, /* RLS MERGE UPDATE USING policy */
+	WCO_RLS_MERGE_DELETE_CHECK	/* RLS MERGE DELETE USING policy */
 } WCOKind;
 
 typedef struct WithCheckOption
@@ -1538,6 +1544,39 @@ typedef struct CommonTableExpr
 	 ((Query *) (cte)->ctequery)->returningList)
 
 /*
+ * MergeWhenClause -
+ *		raw parser representation of a WHEN clause in a MERGE statement
+ *
+ * This is transformed into MergeAction by parse analysis
+ */
+typedef struct MergeWhenClause
+{
+	NodeTag		type;
+	bool		matched;		/* true=MATCHED, false=NOT MATCHED */
+	CmdType		commandType;	/* INSERT/UPDATE/DELETE/DO NOTHING */
+	OverridingKind override;	/* OVERRIDING clause */
+	Node	   *condition;		/* WHEN conditions (raw parser) */
+	List	   *targetList;		/* INSERT/UPDATE targetlist */
+	/* the following members are only used in INSERT actions */
+	List	   *values;			/* VALUES to INSERT, or NULL */
+} MergeWhenClause;
+
+/*
+ * MergeAction -
+ *		Transformed representation of a WHEN clause in a MERGE statement
+ */
+typedef struct MergeAction
+{
+	NodeTag		type;
+	bool		matched;		/* true=MATCHED, false=NOT MATCHED */
+	CmdType		commandType;	/* INSERT/UPDATE/DELETE/DO NOTHING */
+	OverridingKind override;	/* OVERRIDING clause */
+	Node	   *qual;			/* transformed WHEN conditions */
+	List	   *targetList;		/* the target list (of TargetEntry) */
+	List	   *updateColnos;	/* target attribute numbers of an UPDATE */
+} MergeAction;
+
+/*
  * TriggerTransition -
  *	   representation of transition row or table naming clause
  *
@@ -1738,6 +1777,20 @@ typedef struct UpdateStmt
 } UpdateStmt;
 
 /* ----------------------
+ *		Merge Statement
+ * ----------------------
+ */
+typedef struct MergeStmt
+{
+	NodeTag		type;
+	RangeVar   *relation;		/* target relation to merge into */
+	Node	   *sourceRelation; /* source relation */
+	Node	   *joinCondition;	/* join condition between source and target */
+	List	   *mergeWhenClauses;	/* list of MergeWhenClause(es) */
+	WithClause *withClause;		/* WITH clause */
+} MergeStmt;
+
+/* ----------------------
  *		Select Statement
  *
  * A "simple" SELECT is represented in the output of gram.y by a single
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h
index 1f3845b3fec..365000bdcdb 100644
--- a/src/include/nodes/pathnodes.h
+++ b/src/include/nodes/pathnodes.h
@@ -1875,7 +1875,7 @@ typedef struct LockRowsPath
 } LockRowsPath;
 
 /*
- * ModifyTablePath represents performing INSERT/UPDATE/DELETE modifications
+ * ModifyTablePath represents performing INSERT/UPDATE/DELETE/MERGE
  *
  * We represent most things that will be in the ModifyTable plan node
  * literally, except we have a child Path not Plan.  But analysis of the
@@ -1885,7 +1885,7 @@ typedef struct ModifyTablePath
 {
 	Path		path;
 	Path	   *subpath;		/* Path producing source data */
-	CmdType		operation;		/* INSERT, UPDATE, or DELETE */
+	CmdType		operation;		/* INSERT, UPDATE, DELETE, or MERGE */
 	bool		canSetTag;		/* do we set the command tag/es_processed? */
 	Index		nominalRelation;	/* Parent RT index for use of EXPLAIN */
 	Index		rootRelation;	/* Root RT index, if target is partitioned */
@@ -1897,6 +1897,8 @@ typedef struct ModifyTablePath
 	List	   *rowMarks;		/* PlanRowMarks (non-locking only) */
 	OnConflictExpr *onconflict; /* ON CONFLICT clause, or NULL */
 	int			epqParam;		/* ID of Param for EvalPlanQual re-eval */
+	List	   *mergeActionLists;	/* per-target-table lists of actions for
+									 * MERGE */
 } ModifyTablePath;
 
 /*
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 0b518ce6b28..50ef3dda051 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -19,6 +19,7 @@
 #include "lib/stringinfo.h"
 #include "nodes/bitmapset.h"
 #include "nodes/lockoptions.h"
+#include "nodes/parsenodes.h"
 #include "nodes/primnodes.h"
 
 
@@ -43,7 +44,7 @@ typedef struct PlannedStmt
 {
 	NodeTag		type;
 
-	CmdType		commandType;	/* select|insert|update|delete|utility */
+	CmdType		commandType;	/* select|insert|update|delete|merge|utility */
 
 	uint64		queryId;		/* query identifier (copied from Query) */
 
@@ -217,7 +218,7 @@ typedef struct ProjectSet
 typedef struct ModifyTable
 {
 	Plan		plan;
-	CmdType		operation;		/* INSERT, UPDATE, or DELETE */
+	CmdType		operation;		/* INSERT, UPDATE, DELETE, or MERGE */
 	bool		canSetTag;		/* do we set the command tag/es_processed? */
 	Index		nominalRelation;	/* Parent RT index for use of EXPLAIN */
 	Index		rootRelation;	/* Root RT index, if target is partitioned */
@@ -237,6 +238,8 @@ typedef struct ModifyTable
 	Node	   *onConflictWhere;	/* WHERE for ON CONFLICT UPDATE */
 	Index		exclRelRTI;		/* RTI of the EXCLUDED pseudo relation */
 	List	   *exclRelTlist;	/* tlist of the EXCLUDED pseudo relation */
+	List	   *mergeActionLists;	/* per-target-table lists of actions for
+									 * MERGE */
 } ModifyTable;
 
 struct PartitionPruneInfo;		/* forward reference to struct below */
diff --git a/src/include/optimizer/pathnode.h b/src/include/optimizer/pathnode.h
index 620eeda2d60..6eca547af80 100644
--- a/src/include/optimizer/pathnode.h
+++ b/src/include/optimizer/pathnode.h
@@ -276,7 +276,7 @@ extern ModifyTablePath *create_modifytable_path(PlannerInfo *root,
 												List *updateColnosLists,
 												List *withCheckOptionLists, List *returningLists,
 												List *rowMarks, OnConflictExpr *onconflict,
-												int epqParam);
+												List *mergeActionLists, int epqParam);
 extern LimitPath *create_limit_path(PlannerInfo *root, RelOptInfo *rel,
 									Path *subpath,
 									Node *limitOffset, Node *limitCount,
diff --git a/src/include/optimizer/prep.h b/src/include/optimizer/prep.h
index 006b4d02c3e..2b11ff1d1fe 100644
--- a/src/include/optimizer/prep.h
+++ b/src/include/optimizer/prep.h
@@ -21,6 +21,7 @@
 /*
  * prototypes for prepjointree.c
  */
+extern void transform_MERGE_to_join(Query *parse);
 extern void replace_empty_jointree(Query *parse);
 extern void pull_up_sublinks(PlannerInfo *root);
 extern void preprocess_function_rtes(PlannerInfo *root);
diff --git a/src/include/parser/analyze.h b/src/include/parser/analyze.h
index b30cbd26bf8..c69920d1087 100644
--- a/src/include/parser/analyze.h
+++ b/src/include/parser/analyze.h
@@ -39,6 +39,11 @@ extern Query *parse_sub_analyze(Node *parseTree, ParseState *parentParseState,
 								bool locked_from_parent,
 								bool resolve_unknowns);
 
+extern List *transformInsertRow(ParseState *pstate, List *exprlist,
+								List *stmtcols, List *icolumns, List *attrnos,
+								bool strip_indirection);
+extern List *transformUpdateTargetList(ParseState *pstate,
+									   List *targetList);
 extern Query *transformTopLevelStmt(ParseState *pstate, RawStmt *parseTree);
 extern Query *transformStmt(ParseState *pstate, Node *parseTree);
 
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index f44440d4a94..10829941e0d 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -259,8 +259,10 @@ PG_KEYWORD("locked", LOCKED, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("logged", LOGGED, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("mapping", MAPPING, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("match", MATCH, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("matched", MATCHED, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("materialized", MATERIALIZED, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("maxvalue", MAXVALUE, UNRESERVED_KEYWORD, BARE_LABEL)
+PG_KEYWORD("merge", MERGE, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("method", METHOD, UNRESERVED_KEYWORD, BARE_LABEL)
 PG_KEYWORD("minute", MINUTE_P, UNRESERVED_KEYWORD, AS_LABEL)
 PG_KEYWORD("minvalue", MINVALUE, UNRESERVED_KEYWORD, BARE_LABEL)
diff --git a/src/include/parser/parse_merge.h b/src/include/parser/parse_merge.h
new file mode 100644
index 00000000000..1a1baa1f485
--- /dev/null
+++ b/src/include/parser/parse_merge.h
@@ -0,0 +1,21 @@
+/*-------------------------------------------------------------------------
+ *
+ * parse_merge.h
+ *		handle MERGE statement in parser
+ *
+ *
+ * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/parser/parse_merge.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef PARSE_MERGE_H
+#define PARSE_MERGE_H
+
+#include "parser/parse_node.h"
+
+extern Query *transformMergeStmt(ParseState *pstate, MergeStmt *stmt);
+
+#endif							/* PARSE_MERGE_H */
diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h
index 8c859d0d0e4..cf9c7590258 100644
--- a/src/include/parser/parse_node.h
+++ b/src/include/parser/parse_node.h
@@ -55,6 +55,7 @@ typedef enum ParseExprKind
 	EXPR_KIND_INSERT_TARGET,	/* INSERT target list item */
 	EXPR_KIND_UPDATE_SOURCE,	/* UPDATE assignment source item */
 	EXPR_KIND_UPDATE_TARGET,	/* UPDATE assignment target item */
+	EXPR_KIND_MERGE_WHEN,		/* MERGE WHEN [NOT] MATCHED condition */
 	EXPR_KIND_GROUP_BY,			/* GROUP BY */
 	EXPR_KIND_ORDER_BY,			/* ORDER BY */
 	EXPR_KIND_DISTINCT_ON,		/* DISTINCT ON */
@@ -135,7 +136,7 @@ typedef Node *(*CoerceParamHook) (ParseState *pstate, Param *param,
  * p_parent_cte: CommonTableExpr that immediately contains the current query,
  * if any.
  *
- * p_target_relation: target relation, if query is INSERT, UPDATE, or DELETE.
+ * p_target_relation: target relation, if query is INSERT/UPDATE/DELETE/MERGE
  *
  * p_target_nsitem: target relation's ParseNamespaceItem.
  *
@@ -189,7 +190,7 @@ struct ParseState
 	List	   *p_ctenamespace; /* current namespace for common table exprs */
 	List	   *p_future_ctes;	/* common table exprs not yet in namespace */
 	CommonTableExpr *p_parent_cte;	/* this query's containing CTE */
-	Relation	p_target_relation;	/* INSERT/UPDATE/DELETE target rel */
+	Relation	p_target_relation;	/* INSERT/UPDATE/DELETE/MERGE target rel */
 	ParseNamespaceItem *p_target_nsitem;	/* target rel's NSItem, or NULL */
 	bool		p_is_insert;	/* process assignment like INSERT not UPDATE */
 	List	   *p_windowdefs;	/* raw representations of window clauses */
diff --git a/src/include/parser/parse_relation.h b/src/include/parser/parse_relation.h
index 06dc27995ba..de21c3c6497 100644
--- a/src/include/parser/parse_relation.h
+++ b/src/include/parser/parse_relation.h
@@ -113,7 +113,8 @@ extern List *expandNSItemVars(ParseNamespaceItem *nsitem,
 							  int sublevels_up, int location,
 							  List **colnames);
 extern List *expandNSItemAttrs(ParseState *pstate, ParseNamespaceItem *nsitem,
-							   int sublevels_up, int location);
+							   int sublevels_up, bool require_col_privs,
+							   int location);
 extern int	attnameAttNum(Relation rd, const char *attname, bool sysColOK);
 extern const NameData *attnumAttName(Relation rd, int attid);
 extern Oid	attnumTypeId(Relation rd, int attid);
diff --git a/src/include/tcop/cmdtaglist.h b/src/include/tcop/cmdtaglist.h
index 4bc7ddf4107..2b1163ce33a 100644
--- a/src/include/tcop/cmdtaglist.h
+++ b/src/include/tcop/cmdtaglist.h
@@ -186,6 +186,7 @@ PG_CMDTAG(CMDTAG_INSERT, "INSERT", false, false, true)
 PG_CMDTAG(CMDTAG_LISTEN, "LISTEN", false, false, false)
 PG_CMDTAG(CMDTAG_LOAD, "LOAD", false, false, false)
 PG_CMDTAG(CMDTAG_LOCK_TABLE, "LOCK TABLE", false, false, false)
+PG_CMDTAG(CMDTAG_MERGE, "MERGE", false, false, true)
 PG_CMDTAG(CMDTAG_MOVE, "MOVE", false, false, true)
 PG_CMDTAG(CMDTAG_NOTIFY, "NOTIFY", false, false, false)
 PG_CMDTAG(CMDTAG_PREPARE, "PREPARE", false, false, false)