execnodes.h

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	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;

/* ----------------
 *	 IndexScanState information
 *
 *		NumIndices		   number of indices in this scan
 *		IndexPtr		   current index in use
 *		ScanKeys		   Skey structures to scan index rels
 *		NumScanKeys		   array of no of keys in each Skey struct
 *		RuntimeKeyInfo	   array of array of exprstates for Skeys
 *						   that will be evaluated at runtime
 *		RuntimeContext	   expr context for evaling runtime Skeys
 *		RuntimeKeysReady   true if runtime Skeys have been computed
 *		RelationDescs	   ptr to array of relation descriptors
 *		ScanDescs		   ptr to array of scan descriptors
 *		DupHash			   hashtable for recognizing dups in multiple scan
 *		MaxHash			   max # entries we will allow in hashtable
 * ----------------
 */
typedef struct IndexScanState
{
	ScanState	ss;				/* its first field is NodeTag */
	List	   *indxqual;
	List	   *indxqualorig;
	int			iss_NumIndices;
	int			iss_IndexPtr;
	int			iss_MarkIndexPtr;
	ScanKey    *iss_ScanKeys;
	int		   *iss_NumScanKeys;
	ExprState ***iss_RuntimeKeyInfo;
	ExprContext *iss_RuntimeContext;
	bool		iss_RuntimeKeysReady;
	RelationPtr iss_RelationDescs;
	IndexScanDescPtr iss_ScanDescs;
	HTAB	   *iss_DupHash;
	long		iss_MaxHash;
} IndexScanState;

/* ----------------
 *	 TidScanState information
 *
 *		NumTids		   number of tids in this scan
 *		TidPtr		   current tid in use
 *		TidList		   evaluated item pointers
 * ----------------
 */
typedef struct TidScanState
{
	ScanState	ss;				/* its first field is NodeTag */
	List	   *tss_tideval;	/* 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
 * ----------------
 */
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;

/* ----------------------------------------------------------------
 *				 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
 *
 *		OuterSkipQual	   outerKey1 < innerKey1 ...
 *		InnerSkipQual	   outerKey1 > innerKey1 ...
 *		JoinState		   current "state" of join. see executor.h
 *		MatchedOuter	   true if found a join match for current outer tuple
 *		MatchedInner	   true if found a join match for current inner tuple
 *		OuterTupleSlot	   pointer to slot in tuple table for cur outer tuple
 *		InnerTupleSlot	   pointer to slot in tuple table for cur inner tuple
 *		MarkedTupleSlot    pointer to slot in tuple table for marked tuple
 *		NullOuterTupleSlot prepared null tuple for right outer joins
 *		NullInnerTupleSlot prepared null tuple for left outer joins
 * ----------------
 */
typedef struct MergeJoinState
{
	JoinState	js;				/* its first field is NodeTag */
	List	   *mergeclauses;	/* list of ExprState nodes */
	List	   *mj_OuterSkipQual;		/* list of ExprState nodes */
	List	   *mj_InnerSkipQual;		/* list of ExprState nodes */
	int			mj_JoinState;
	bool		mj_MatchedOuter;
	bool		mj_MatchedInner;
	TupleTableSlot *mj_OuterTupleSlot;
	TupleTableSlot *mj_InnerTupleSlot;
	TupleTableSlot *mj_MarkedTupleSlot;
	TupleTableSlot *mj_NullOuterTupleSlot;
	TupleTableSlot *mj_NullInnerTupleSlot;
} MergeJoinState;

/* ----------------
 *	 HashJoinState information
 *
 *		hj_HashTable			hash table for the hashjoin
 *		hj_CurBucketNo			bucket# for current outer tuple
 *		hj_CurTuple				last inner tuple matched to current outer
 *								tuple, or NULL if starting search
 *								(CurBucketNo and CurTuple are meaningless
 *								 unless OuterTupleSlot is nonempty!)
 *		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_NeedNewOuter			true if need new outer tuple on next call
 *		hj_MatchedOuter			true if found a join match for current outer
 *		hj_hashdone				true if hash-table-build phase is done
 * ----------------
 */
typedef struct HashJoinState
{
	JoinState	js;				/* its first field is NodeTag */
	List	   *hashclauses;	/* list of ExprState nodes */
	HashJoinTable hj_HashTable;
	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;
	bool		hj_NeedNewOuter;
	bool		hj_MatchedOuter;
	bool		hj_hashdone;
} 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 */
	void	   *tuplestorestate;	/* private state of tuplestore.c */
	bool		eof_underlying; /* reached end of underlying plan? */
} MaterialState;

/* ----------------
 *	 SortState information
 * ----------------
 */
typedef struct SortState
{
	ScanState	ss;				/* its first field is NodeTag */
	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 */
	HeapTuple	grp_firstTuple; /* copy of first tuple of current group */
	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 */
	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 priorTuple.
 *		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 */
	HeapTuple	priorTuple;		/* most recently returned tuple, or NULL */
	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 */
	long		offset;			/* current OFFSET value */
	long		count;			/* current COUNT, if any */
	bool		noCount;		/* if true, ignore count */
	LimitStateCond lstate;		/* state machine status, as above */
	long		position;		/* 1-based index of last tuple returned */
	TupleTableSlot *subSlot;	/* tuple last obtained from subplan */
} LimitState;

#endif   /* EXECNODES_H */