execnodes.h

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 */
typedef struct SubqueryScanState
{
	ScanState	ss;				/* its first field is NodeTag */
	PlanState  *subplan;
	EState	   *sss_SubEState;
} SubqueryScanState;

/* ----------------
 *	 FunctionScanState information
 *
 *		Function nodes are used to scan the results of a
 *		function appearing in FROM (typically a function returning set).
 *
 *		tupdesc				expected return tuple description
 *		tuplestorestate		private state of tuplestore.c
 *		funcexpr			state for function expression being evaluated
 * ----------------
 */
typedef struct FunctionScanState
{
	ScanState	ss;				/* its first field is NodeTag */
	TupleDesc	tupdesc;
	Tuplestorestate *tuplestorestate;
	ExprState  *funcexpr;
} FunctionScanState;

/* ----------------
 *	 ValuesScanState information
 *
 *		ValuesScan nodes are used to scan the results of a VALUES list
 *
 *		rowcontext			per-expression-list context
 *		exprlists			array of expression lists being evaluated
 *		array_len			size of array
 *		curr_idx			current array index (0-based)
 *		marked_idx			marked position (for mark/restore)
 *
 *	Note: ss.ps.ps_ExprContext is used to evaluate any qual or projection
 *	expressions attached to the node.  We create a second ExprContext,
 *	rowcontext, in which to build the executor expression state for each
 *	Values sublist.  Resetting this context lets us get rid of expression
 *	state for each row, avoiding major memory leakage over a long values list.
 * ----------------
 */
typedef struct ValuesScanState
{
	ScanState	ss;				/* its first field is NodeTag */
	ExprContext *rowcontext;
	List	  **exprlists;
	int			array_len;
	int			curr_idx;
	int			marked_idx;
} ValuesScanState;

/* ----------------------------------------------------------------
 *				 Join State Information
 * ----------------------------------------------------------------
 */

/* ----------------
 *	 JoinState information
 *
 *		Superclass for state nodes of join plans.
 * ----------------
 */
typedef struct JoinState
{
	PlanState	ps;
	JoinType	jointype;
	List	   *joinqual;		/* JOIN quals (in addition to ps.qual) */
} JoinState;

/* ----------------
 *	 NestLoopState information
 *
 *		NeedNewOuter	   true if need new outer tuple on next call
 *		MatchedOuter	   true if found a join match for current outer tuple
 *		NullInnerTupleSlot prepared null tuple for left outer joins
 * ----------------
 */
typedef struct NestLoopState
{
	JoinState	js;				/* its first field is NodeTag */
	bool		nl_NeedNewOuter;
	bool		nl_MatchedOuter;
	TupleTableSlot *nl_NullInnerTupleSlot;
} NestLoopState;

/* ----------------
 *	 MergeJoinState information
 *
 *		NumClauses		   number of mergejoinable join clauses
 *		Clauses			   info for each mergejoinable clause
 *		JoinState		   current "state" of join.  see execdefs.h
 *		FillOuter		   true if should emit unjoined outer tuples anyway
 *		FillInner		   true if should emit unjoined inner tuples anyway
 *		MatchedOuter	   true if found a join match for current outer tuple
 *		MatchedInner	   true if found a join match for current inner tuple
 *		OuterTupleSlot	   slot in tuple table for cur outer tuple
 *		InnerTupleSlot	   slot in tuple table for cur inner tuple
 *		MarkedTupleSlot    slot in tuple table for marked tuple
 *		NullOuterTupleSlot prepared null tuple for right outer joins
 *		NullInnerTupleSlot prepared null tuple for left outer joins
 *		OuterEContext	   workspace for computing outer tuple's join values
 *		InnerEContext	   workspace for computing inner tuple's join values
 * ----------------
 */
/* private in nodeMergejoin.c: */
typedef struct MergeJoinClauseData *MergeJoinClause;

typedef struct MergeJoinState
{
	JoinState	js;				/* its first field is NodeTag */
	int			mj_NumClauses;
	MergeJoinClause mj_Clauses; /* array of length mj_NumClauses */
	int			mj_JoinState;
	bool		mj_FillOuter;
	bool		mj_FillInner;
	bool		mj_MatchedOuter;
	bool		mj_MatchedInner;
	TupleTableSlot *mj_OuterTupleSlot;
	TupleTableSlot *mj_InnerTupleSlot;
	TupleTableSlot *mj_MarkedTupleSlot;
	TupleTableSlot *mj_NullOuterTupleSlot;
	TupleTableSlot *mj_NullInnerTupleSlot;
	ExprContext *mj_OuterEContext;
	ExprContext *mj_InnerEContext;
} MergeJoinState;

/* ----------------
 *	 HashJoinState information
 *
 *		hj_HashTable			hash table for the hashjoin
 *								(NULL if table not built yet)
 *		hj_CurHashValue			hash value for current outer tuple
 *		hj_CurBucketNo			bucket# for current outer tuple
 *		hj_CurTuple				last inner tuple matched to current outer
 *								tuple, or NULL if starting search
 *								(CurHashValue, CurBucketNo and CurTuple are
 *								 undefined if OuterTupleSlot is empty!)
 *		hj_OuterHashKeys		the outer hash keys in the hashjoin condition
 *		hj_InnerHashKeys		the inner hash keys in the hashjoin condition
 *		hj_HashOperators		the join operators in the hashjoin condition
 *		hj_OuterTupleSlot		tuple slot for outer tuples
 *		hj_HashTupleSlot		tuple slot for hashed tuples
 *		hj_NullInnerTupleSlot	prepared null tuple for left outer joins
 *		hj_FirstOuterTupleSlot	first tuple retrieved from outer plan
 *		hj_NeedNewOuter			true if need new outer tuple on next call
 *		hj_MatchedOuter			true if found a join match for current outer
 *		hj_OuterNotEmpty		true if outer relation known not empty
 * ----------------
 */

/* these structs are defined in executor/hashjoin.h: */
typedef struct HashJoinTupleData *HashJoinTuple;
typedef struct HashJoinTableData *HashJoinTable;

typedef struct HashJoinState
{
	JoinState	js;				/* its first field is NodeTag */
	List	   *hashclauses;	/* list of ExprState nodes */
	HashJoinTable hj_HashTable;
	uint32		hj_CurHashValue;
	int			hj_CurBucketNo;
	HashJoinTuple hj_CurTuple;
	List	   *hj_OuterHashKeys;		/* list of ExprState nodes */
	List	   *hj_InnerHashKeys;		/* list of ExprState nodes */
	List	   *hj_HashOperators;		/* list of operator OIDs */
	TupleTableSlot *hj_OuterTupleSlot;
	TupleTableSlot *hj_HashTupleSlot;
	TupleTableSlot *hj_NullInnerTupleSlot;
	TupleTableSlot *hj_FirstOuterTupleSlot;
	bool		hj_NeedNewOuter;
	bool		hj_MatchedOuter;
	bool		hj_OuterNotEmpty;
} HashJoinState;


/* ----------------------------------------------------------------
 *				 Materialization State Information
 * ----------------------------------------------------------------
 */

/* ----------------
 *	 MaterialState information
 *
 *		materialize nodes are used to materialize the results
 *		of a subplan into a temporary file.
 *
 *		ss.ss_ScanTupleSlot refers to output of underlying plan.
 * ----------------
 */
typedef struct MaterialState
{
	ScanState	ss;				/* its first field is NodeTag */
	bool		randomAccess;	/* need random access to subplan output? */
	bool		eof_underlying; /* reached end of underlying plan? */
	void	   *tuplestorestate;	/* private state of tuplestore.c */
} MaterialState;

/* ----------------
 *	 SortState information
 * ----------------
 */
typedef struct SortState
{
	ScanState	ss;				/* its first field is NodeTag */
	bool		randomAccess;	/* need random access to sort output? */
	bool		sort_Done;		/* sort completed yet? */
	void	   *tuplesortstate; /* private state of tuplesort.c */
} SortState;

/* ---------------------
 *	GroupState information
 * -------------------------
 */
typedef struct GroupState
{
	ScanState	ss;				/* its first field is NodeTag */
	FmgrInfo   *eqfunctions;	/* per-field lookup data for equality fns */
	bool		grp_done;		/* indicates completion of Group scan */
} GroupState;

/* ---------------------
 *	AggState information
 *
 *	ss.ss_ScanTupleSlot refers to output of underlying plan.
 *
 *	Note: ss.ps.ps_ExprContext contains ecxt_aggvalues and
 *	ecxt_aggnulls arrays, which hold the computed agg values for the current
 *	input group during evaluation of an Agg node's output tuple(s).  We
 *	create a second ExprContext, tmpcontext, in which to evaluate input
 *	expressions and run the aggregate transition functions.
 * -------------------------
 */
/* these structs are private in nodeAgg.c: */
typedef struct AggStatePerAggData *AggStatePerAgg;
typedef struct AggStatePerGroupData *AggStatePerGroup;

typedef struct AggState
{
	ScanState	ss;				/* its first field is NodeTag */
	List	   *aggs;			/* all Aggref nodes in targetlist & quals */
	int			numaggs;		/* length of list (could be zero!) */
	FmgrInfo   *eqfunctions;	/* per-grouping-field equality fns */
	FmgrInfo   *hashfunctions;	/* per-grouping-field hash fns */
	AggStatePerAgg peragg;		/* per-Aggref information */
	MemoryContext aggcontext;	/* memory context for long-lived data */
	ExprContext *tmpcontext;	/* econtext for input expressions */
	bool		agg_done;		/* indicates completion of Agg scan */
	/* these fields are used in AGG_PLAIN and AGG_SORTED modes: */
	AggStatePerGroup pergroup;	/* per-Aggref-per-group working state */
	HeapTuple	grp_firstTuple; /* copy of first tuple of current group */
	/* these fields are used in AGG_HASHED mode: */
	TupleHashTable hashtable;	/* hash table with one entry per group */
	TupleTableSlot *hashslot;	/* slot for loading hash table */
	List	   *hash_needed;	/* list of columns needed in hash table */
	bool		table_filled;	/* hash table filled yet? */
	TupleHashIterator hashiter; /* for iterating through hash table */
} AggState;

/* ----------------
 *	 UniqueState information
 *
 *		Unique nodes are used "on top of" sort nodes to discard
 *		duplicate tuples returned from the sort phase.	Basically
 *		all it does is compare the current tuple from the subplan
 *		with the previously fetched tuple (stored in its result slot).
 *		If the two are identical in all interesting fields, then
 *		we just fetch another tuple from the sort and try again.
 * ----------------
 */
typedef struct UniqueState
{
	PlanState	ps;				/* its first field is NodeTag */
	FmgrInfo   *eqfunctions;	/* per-field lookup data for equality fns */
	MemoryContext tempContext;	/* short-term context for comparisons */
} UniqueState;

/* ----------------
 *	 HashState information
 * ----------------
 */
typedef struct HashState
{
	PlanState	ps;				/* its first field is NodeTag */
	HashJoinTable hashtable;	/* hash table for the hashjoin */
	List	   *hashkeys;		/* list of ExprState nodes */
	/* hashkeys is same as parent's hj_InnerHashKeys */
} HashState;

/* ----------------
 *	 SetOpState information
 *
 *		SetOp nodes are used "on top of" sort nodes to discard
 *		duplicate tuples returned from the sort phase.	These are
 *		more complex than a simple Unique since we have to count
 *		how many duplicates to return.
 * ----------------
 */
typedef struct SetOpState
{
	PlanState	ps;				/* its first field is NodeTag */
	FmgrInfo   *eqfunctions;	/* per-field lookup data for equality fns */
	bool		subplan_done;	/* has subplan returned EOF? */
	long		numLeft;		/* number of left-input dups of cur group */
	long		numRight;		/* number of right-input dups of cur group */
	long		numOutput;		/* number of dups left to output */
	MemoryContext tempContext;	/* short-term context for comparisons */
} SetOpState;

/* ----------------
 *	 LimitState information
 *
 *		Limit nodes are used to enforce LIMIT/OFFSET clauses.
 *		They just select the desired subrange of their subplan's output.
 *
 * offset is the number of initial tuples to skip (0 does nothing).
 * count is the number of tuples to return after skipping the offset tuples.
 * If no limit count was specified, count is undefined and noCount is true.
 * When lstate == LIMIT_INITIAL, offset/count/noCount haven't been set yet.
 * ----------------
 */
typedef enum
{
	LIMIT_INITIAL,				/* initial state for LIMIT node */
	LIMIT_EMPTY,				/* there are no returnable rows */
	LIMIT_INWINDOW,				/* have returned a row in the window */
	LIMIT_SUBPLANEOF,			/* at EOF of subplan (within window) */
	LIMIT_WINDOWEND,			/* stepped off end of window */
	LIMIT_WINDOWSTART			/* stepped off beginning of window */
} LimitStateCond;

typedef struct LimitState
{
	PlanState	ps;				/* its first field is NodeTag */
	ExprState  *limitOffset;	/* OFFSET parameter, or NULL if none */
	ExprState  *limitCount;		/* COUNT parameter, or NULL if none */
	int64		offset;			/* current OFFSET value */
	int64		count;			/* current COUNT, if any */
	bool		noCount;		/* if true, ignore count */
	LimitStateCond lstate;		/* state machine status, as above */
	int64		position;		/* 1-based index of last tuple returned */
	TupleTableSlot *subSlot;	/* tuple last obtained from subplan */
} LimitState;

#endif   /* EXECNODES_H */