execnodes.h

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} RowCompareExprState;

/* ----------------
 *		CoalesceExprState node
 * ----------------
 */
typedef struct CoalesceExprState
{
	ExprState	xprstate;
	List	   *args;			/* the arguments */
} CoalesceExprState;

/* ----------------
 *		MinMaxExprState node
 * ----------------
 */
typedef struct MinMaxExprState
{
	ExprState	xprstate;
	List	   *args;			/* the arguments */
	FmgrInfo	cfunc;			/* lookup info for comparison func */
} MinMaxExprState;

/* ----------------
 *		NullTestState node
 * ----------------
 */
typedef struct NullTestState
{
	ExprState	xprstate;
	ExprState  *arg;			/* input expression */
	bool		argisrow;		/* T if input is of a composite type */
	/* used only if argisrow: */
	TupleDesc	argdesc;		/* tupdesc for most recent input */
} NullTestState;

/* ----------------
 *		CoerceToDomainState node
 * ----------------
 */
typedef struct CoerceToDomainState
{
	ExprState	xprstate;
	ExprState  *arg;			/* input expression */
	/* Cached list of constraints that need to be checked */
	List	   *constraints;	/* list of DomainConstraintState nodes */
} CoerceToDomainState;

/*
 * DomainConstraintState - one item to check during CoerceToDomain
 *
 * Note: this is just a Node, and not an ExprState, because it has no
 * corresponding Expr to link to.  Nonetheless it is part of an ExprState
 * tree, so we give it a name following the xxxState convention.
 */
typedef enum DomainConstraintType
{
	DOM_CONSTRAINT_NOTNULL,
	DOM_CONSTRAINT_CHECK
} DomainConstraintType;

typedef struct DomainConstraintState
{
	NodeTag		type;
	DomainConstraintType constrainttype;		/* constraint type */
	char	   *name;			/* name of constraint (for error msgs) */
	ExprState  *check_expr;		/* for CHECK, a boolean expression */
} DomainConstraintState;


/* ----------------------------------------------------------------
 *				 Executor State Trees
 *
 * An executing query has a PlanState tree paralleling the Plan tree
 * that describes the plan.
 * ----------------------------------------------------------------
 */

/* ----------------
 *		PlanState node
 *
 * We never actually instantiate any PlanState nodes; this is just the common
 * abstract superclass for all PlanState-type nodes.
 * ----------------
 */
typedef struct PlanState
{
	NodeTag		type;

	Plan	   *plan;			/* associated Plan node */

	EState	   *state;			/* at execution time, state's of individual
								 * nodes point to one EState for the whole
								 * top-level plan */

	struct Instrumentation *instrument; /* Optional runtime stats for this
										 * plan node */

	/*
	 * Common structural data for all Plan types.  These links to subsidiary
	 * state trees parallel links in the associated plan tree (except for the
	 * subPlan list, which does not exist in the plan tree).
	 */
	List	   *targetlist;		/* target list to be computed at this node */
	List	   *qual;			/* implicitly-ANDed qual conditions */
	struct PlanState *lefttree; /* input plan tree(s) */
	struct PlanState *righttree;
	List	   *initPlan;		/* Init SubPlanState nodes (un-correlated expr
								 * subselects) */
	List	   *subPlan;		/* SubPlanState nodes in my expressions */

	/*
	 * State for management of parameter-change-driven rescanning
	 */
	Bitmapset  *chgParam;		/* set of IDs of changed Params */

	/*
	 * Other run-time state needed by most if not all node types.
	 */
	TupleTableSlot *ps_OuterTupleSlot;	/* slot for current "outer" tuple */
	TupleTableSlot *ps_ResultTupleSlot; /* slot for my result tuples */
	ExprContext *ps_ExprContext;	/* node's expression-evaluation context */
	ProjectionInfo *ps_ProjInfo;	/* info for doing tuple projection */
	bool		ps_TupFromTlist;/* state flag for processing set-valued
								 * functions in targetlist */
} PlanState;

/* ----------------
 *	these are are defined to avoid confusion problems with "left"
 *	and "right" and "inner" and "outer".  The convention is that
 *	the "left" plan is the "outer" plan and the "right" plan is
 *	the inner plan, but these make the code more readable.
 * ----------------
 */
#define innerPlanState(node)		(((PlanState *)(node))->righttree)
#define outerPlanState(node)		(((PlanState *)(node))->lefttree)


/* ----------------
 *	 ResultState information
 * ----------------
 */
typedef struct ResultState
{
	PlanState	ps;				/* its first field is NodeTag */
	ExprState  *resconstantqual;
	bool		rs_done;		/* are we done? */
	bool		rs_checkqual;	/* do we need to check the qual? */
} ResultState;

/* ----------------
 *	 AppendState information
 *
 *		nplans			how many plans are in the list
 *		whichplan		which plan is being executed (0 .. n-1)
 *		firstplan		first plan to execute (usually 0)
 *		lastplan		last plan to execute (usually n-1)
 * ----------------
 */
typedef struct AppendState
{
	PlanState	ps;				/* its first field is NodeTag */
	PlanState **appendplans;	/* array of PlanStates for my inputs */
	int			as_nplans;
	int			as_whichplan;
	int			as_firstplan;
	int			as_lastplan;
} AppendState;

/* ----------------
 *	 BitmapAndState information
 * ----------------
 */
typedef struct BitmapAndState
{
	PlanState	ps;				/* its first field is NodeTag */
	PlanState **bitmapplans;	/* array of PlanStates for my inputs */
	int			nplans;			/* number of input plans */
} BitmapAndState;

/* ----------------
 *	 BitmapOrState information
 * ----------------
 */
typedef struct BitmapOrState
{
	PlanState	ps;				/* its first field is NodeTag */
	PlanState **bitmapplans;	/* array of PlanStates for my inputs */
	int			nplans;			/* number of input plans */
} BitmapOrState;

/* ----------------------------------------------------------------
 *				 Scan State Information
 * ----------------------------------------------------------------
 */

/* ----------------
 *	 ScanState information
 *
 *		ScanState extends PlanState for node types that represent
 *		scans of an underlying relation.  It can also be used for nodes
 *		that scan the output of an underlying plan node --- in that case,
 *		only ScanTupleSlot is actually useful, and it refers to the tuple
 *		retrieved from the subplan.
 *
 *		currentRelation    relation being scanned (NULL if none)
 *		currentScanDesc    current scan descriptor for scan (NULL if none)
 *		ScanTupleSlot	   pointer to slot in tuple table holding scan tuple
 * ----------------
 */
typedef struct ScanState
{
	PlanState	ps;				/* its first field is NodeTag */
	Relation	ss_currentRelation;
	HeapScanDesc ss_currentScanDesc;
	TupleTableSlot *ss_ScanTupleSlot;
} ScanState;

/*
 * SeqScan uses a bare ScanState as its state node, since it needs
 * no additional fields.
 */
typedef ScanState SeqScanState;

/*
 * These structs store information about index quals that don't have simple
 * constant right-hand sides.  See comments for ExecIndexBuildScanKeys()
 * for discussion.
 */
typedef struct
{
	ScanKey		scan_key;		/* scankey to put value into */
	ExprState  *key_expr;		/* expr to evaluate to get value */
} IndexRuntimeKeyInfo;

typedef struct
{
	ScanKey		scan_key;		/* scankey to put value into */
	ExprState  *array_expr;		/* expr to evaluate to get array value */
	int			next_elem;		/* next array element to use */
	int			num_elems;		/* number of elems in current array value */
	Datum	   *elem_values;	/* array of num_elems Datums */
	bool	   *elem_nulls;		/* array of num_elems is-null flags */
} IndexArrayKeyInfo;

/* ----------------
 *	 IndexScanState information
 *
 *		indexqualorig	   execution state for indexqualorig expressions
 *		ScanKeys		   Skey structures to scan index rel
 *		NumScanKeys		   number of Skey structs
 *		RuntimeKeys		   info about Skeys that must be evaluated at runtime
 *		NumRuntimeKeys	   number of RuntimeKeys structs
 *		RuntimeKeysReady   true if runtime Skeys have been computed
 *		RuntimeContext	   expr context for evaling runtime Skeys
 *		RelationDesc	   index relation descriptor
 *		ScanDesc		   index scan descriptor
 * ----------------
 */
typedef struct IndexScanState
{
	ScanState	ss;				/* its first field is NodeTag */
	List	   *indexqualorig;
	ScanKey		iss_ScanKeys;
	int			iss_NumScanKeys;
	IndexRuntimeKeyInfo *iss_RuntimeKeys;
	int			iss_NumRuntimeKeys;
	bool		iss_RuntimeKeysReady;
	ExprContext *iss_RuntimeContext;
	Relation	iss_RelationDesc;
	IndexScanDesc iss_ScanDesc;
} IndexScanState;

/* ----------------
 *	 BitmapIndexScanState information
 *
 *		result			   bitmap to return output into, or NULL
 *		ScanKeys		   Skey structures to scan index rel
 *		NumScanKeys		   number of Skey structs
 *		RuntimeKeys		   info about Skeys that must be evaluated at runtime
 *		NumRuntimeKeys	   number of RuntimeKeys structs
 *		ArrayKeys		   info about Skeys that come from ScalarArrayOpExprs
 *		NumArrayKeys	   number of ArrayKeys structs
 *		RuntimeKeysReady   true if runtime Skeys have been computed
 *		RuntimeContext	   expr context for evaling runtime Skeys
 *		RelationDesc	   index relation descriptor
 *		ScanDesc		   index scan descriptor
 * ----------------
 */
typedef struct BitmapIndexScanState
{
	ScanState	ss;				/* its first field is NodeTag */
	TIDBitmap  *biss_result;
	ScanKey		biss_ScanKeys;
	int			biss_NumScanKeys;
	IndexRuntimeKeyInfo *biss_RuntimeKeys;
	int			biss_NumRuntimeKeys;
	IndexArrayKeyInfo *biss_ArrayKeys;
	int			biss_NumArrayKeys;
	bool		biss_RuntimeKeysReady;
	ExprContext *biss_RuntimeContext;
	Relation	biss_RelationDesc;
	IndexScanDesc biss_ScanDesc;
} BitmapIndexScanState;

/* ----------------
 *	 BitmapHeapScanState information
 *
 *		bitmapqualorig	   execution state for bitmapqualorig expressions
 *		tbm				   bitmap obtained from child index scan(s)
 *		tbmres			   current-page data
 * ----------------
 */
typedef struct BitmapHeapScanState
{
	ScanState	ss;				/* its first field is NodeTag */
	List	   *bitmapqualorig;
	TIDBitmap  *tbm;
	TBMIterateResult *tbmres;
} BitmapHeapScanState;

/* ----------------
 *	 TidScanState information
 *
 *		NumTids		   number of tids in this scan
 *		TidPtr		   index of currently fetched tid
 *		TidList		   evaluated item pointers (array of size NumTids)
 * ----------------
 */
typedef struct TidScanState
{
	ScanState	ss;				/* its first field is NodeTag */
	List	   *tss_tidquals;	/* list of ExprState nodes */
	int			tss_NumTids;
	int			tss_TidPtr;
	int			tss_MarkTidPtr;
	ItemPointerData *tss_TidList;
	HeapTupleData tss_htup;
} TidScanState;

/* ----------------
 *	 SubqueryScanState information
 *
 *		SubqueryScanState is used for scanning a sub-query in the range table.
 *		The sub-query will have its own EState, which we save here.
 *		ScanTupleSlot references the current output tuple of the sub-query.
 *
 *		SubEState		   exec state for sub-query
 * ----------------