execnodes.h

/*-------------------------------------------------------------------------
 *
 * execnodes.h
 *	  definitions for executor state nodes
 *
 *
 * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/nodes/execnodes.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef EXECNODES_H
#define EXECNODES_H

#include "access/genam.h"
#include "access/heapam.h"
#include "executor/instrument.h"
#include "nodes/params.h"
#include "nodes/plannodes.h"
#include "utils/reltrigger.h"
#include "utils/sortsupport.h"
#include "utils/tuplestore.h"


/* ----------------
 *	  IndexInfo information
 *
 *		this struct holds the information needed to construct new index
 *		entries for a particular index.  Used for both index_build and
 *		retail creation of index entries.
 *
 *		NumIndexAttrs		number of columns in this index
 *		KeyAttrNumbers		underlying-rel attribute numbers used as keys
 *							(zeroes indicate expressions)
 *		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
 *		PredicateState		exec state for predicate, or NIL if none
 *		ExclusionOps		Per-column exclusion operators, or NULL if none
 *		ExclusionProcs		Underlying function OIDs for ExclusionOps
 *		ExclusionStrats		Opclass strategy numbers for ExclusionOps
 *		Unique				is it a unique index?
 *		ReadyForInserts		is it valid for inserts?
 *		Concurrent			are we doing a concurrent index build?
 *		BrokenHotChain		did we detect any broken HOT chains?
 *
 * ii_Concurrent and ii_BrokenHotChain are used only during index build;
 * they're conventionally set to false otherwise.
 * ----------------
 */
typedef struct IndexInfo
{
	NodeTag		type;
	int			ii_NumIndexAttrs;
	AttrNumber	ii_KeyAttrNumbers[INDEX_MAX_KEYS];
	List	   *ii_Expressions; /* list of Expr */
	List	   *ii_ExpressionsState;	/* list of ExprState */
	List	   *ii_Predicate;	/* list of Expr */
	List	   *ii_PredicateState;		/* list of ExprState */
	Oid		   *ii_ExclusionOps;	/* array with one entry per column */
	Oid		   *ii_ExclusionProcs;		/* array with one entry per column */
	uint16	   *ii_ExclusionStrats;		/* array with one entry per column */
	bool		ii_Unique;
	bool		ii_ReadyForInserts;
	bool		ii_Concurrent;
	bool		ii_BrokenHotChain;
} IndexInfo;

/* ----------------
 *	  ExprContext_CB
 *
 *		List of callbacks to be called at ExprContext shutdown.
 * ----------------
 */
typedef void (*ExprContextCallbackFunction) (Datum arg);

typedef struct ExprContext_CB
{
	struct ExprContext_CB *next;
	ExprContextCallbackFunction function;
	Datum		arg;
} ExprContext_CB;

/* ----------------
 *	  ExprContext
 *
 *		This class holds the "current context" information
 *		needed to evaluate expressions for doing tuple qualifications
 *		and tuple projections.	For example, if an expression refers
 *		to an attribute in the current inner tuple then we need to know
 *		what the current inner tuple is and so we look at the expression
 *		context.
 *
 *	There are two memory contexts associated with an ExprContext:
 *	* ecxt_per_query_memory is a query-lifespan context, typically the same
 *	  context the ExprContext node itself is allocated in.	This context
 *	  can be used for purposes such as storing function call cache info.
 *	* ecxt_per_tuple_memory is a short-term context for expression results.
 *	  As the name suggests, it will typically be reset once per tuple,
 *	  before we begin to evaluate expressions for that tuple.  Each
 *	  ExprContext normally has its very own per-tuple memory context.
 *
 *	CurrentMemoryContext should be set to ecxt_per_tuple_memory before
 *	calling ExecEvalExpr() --- see ExecEvalExprSwitchContext().
 * ----------------
 */
typedef struct ExprContext
{
	NodeTag		type;

	/* Tuples that Var nodes in expression may refer to */
	TupleTableSlot *ecxt_scantuple;
	TupleTableSlot *ecxt_innertuple;
	TupleTableSlot *ecxt_outertuple;

	/* Memory contexts for expression evaluation --- see notes above */
	MemoryContext ecxt_per_query_memory;
	MemoryContext ecxt_per_tuple_memory;

	/* Values to substitute for Param nodes in expression */
	ParamExecData *ecxt_param_exec_vals;		/* for PARAM_EXEC params */
	ParamListInfo ecxt_param_list_info; /* for other param types */

	/*
	 * Values to substitute for Aggref nodes in the expressions of an Agg
	 * node, or for WindowFunc nodes within a WindowAgg node.
	 */
	Datum	   *ecxt_aggvalues; /* precomputed values for aggs/windowfuncs */
	bool	   *ecxt_aggnulls;	/* null flags for aggs/windowfuncs */

	/* Value to substitute for CaseTestExpr nodes in expression */
	Datum		caseValue_datum;
	bool		caseValue_isNull;

	/* Value to substitute for CoerceToDomainValue nodes in expression */
	Datum		domainValue_datum;
	bool		domainValue_isNull;

	/* Link to containing EState (NULL if a standalone ExprContext) */
	struct EState *ecxt_estate;

	/* Functions to call back when ExprContext is shut down */
	ExprContext_CB *ecxt_callbacks;
} ExprContext;

/*
 * Set-result status returned by ExecEvalExpr()
 */
typedef enum
{
	ExprSingleResult,			/* expression does not return a set */
	ExprMultipleResult,			/* this result is an element of a set */
	ExprEndResult				/* there are no more elements in the set */
} ExprDoneCond;

/*
 * Return modes for functions returning sets.  Note values must be chosen
 * as separate bits so that a bitmask can be formed to indicate supported
 * modes.  SFRM_Materialize_Random and SFRM_Materialize_Preferred are
 * auxiliary flags about SFRM_Materialize mode, rather than separate modes.
 */
typedef enum
{
	SFRM_ValuePerCall = 0x01,	/* one value returned per call */
	SFRM_Materialize = 0x02,	/* result set instantiated in Tuplestore */
	SFRM_Materialize_Random = 0x04,		/* Tuplestore needs randomAccess */
	SFRM_Materialize_Preferred = 0x08	/* caller prefers Tuplestore */
} SetFunctionReturnMode;

/*
 * When calling a function that might return a set (multiple rows),
 * a node of this type is passed as fcinfo->resultinfo to allow
 * return status to be passed back.  A function returning set should
 * raise an error if no such resultinfo is provided.
 */
typedef struct ReturnSetInfo
{
	NodeTag		type;
	/* values set by caller: */
	ExprContext *econtext;		/* context function is being called in */
	TupleDesc	expectedDesc;	/* tuple descriptor expected by caller */
	int			allowedModes;	/* bitmask: return modes caller can handle */
	/* result status from function (but pre-initialized by caller): */
	SetFunctionReturnMode returnMode;	/* actual return mode */
	ExprDoneCond isDone;		/* status for ValuePerCall mode */
	/* fields filled by function in Materialize return mode: */
	Tuplestorestate *setResult; /* holds the complete returned tuple set */
	TupleDesc	setDesc;		/* actual descriptor for returned tuples */
} ReturnSetInfo;

/* ----------------
 *		ProjectionInfo node information
 *
 *		This is all the information needed to perform projections ---
 *		that is, form new tuples by evaluation of targetlist expressions.
 *		Nodes which need to do projections create one of these.
 *
 *		ExecProject() evaluates the tlist, forms a tuple, and stores it
 *		in the given slot.	Note that the result will be a "virtual" tuple
 *		unless ExecMaterializeSlot() is then called to force it to be
 *		converted to a physical tuple.	The slot must have a tupledesc
 *		that matches the output of the tlist!
 *
 *		The planner very often produces tlists that consist entirely of
 *		simple Var references (lower levels of a plan tree almost always
 *		look like that).  And top-level tlists are often mostly Vars too.
 *		We therefore optimize execution of simple-Var tlist entries.
 *		The pi_targetlist list actually contains only the tlist entries that
 *		aren't simple Vars, while those that are Vars are processed using the
 *		varSlotOffsets/varNumbers/varOutputCols arrays.
 *
 *		The lastXXXVar fields are used to optimize fetching of fields from
 *		input tuples: they let us do a slot_getsomeattrs() call to ensure
 *		that all needed attributes are extracted in one pass.
 *
 *		targetlist		target list for projection (non-Var expressions only)
 *		exprContext		expression context in which to evaluate targetlist
 *		slot			slot to place projection result in
 *		itemIsDone		workspace array for ExecProject
 *		directMap		true if varOutputCols[] is an identity map
 *		numSimpleVars	number of simple Vars found in original tlist
 *		varSlotOffsets	array indicating which slot each simple Var is from
 *		varNumbers		array containing input attr numbers of simple Vars
 *		varOutputCols	array containing output attr numbers of simple Vars
 *		lastInnerVar	highest attnum from inner tuple slot (0 if none)
 *		lastOuterVar	highest attnum from outer tuple slot (0 if none)
 *		lastScanVar		highest attnum from scan tuple slot (0 if none)
 * ----------------
 */
typedef struct ProjectionInfo
{
	NodeTag		type;
	List	   *pi_targetlist;
	ExprContext *pi_exprContext;
	TupleTableSlot *pi_slot;
	ExprDoneCond *pi_itemIsDone;
	bool		pi_directMap;
	int			pi_numSimpleVars;
	int		   *pi_varSlotOffsets;
	int		   *pi_varNumbers;
	int		   *pi_varOutputCols;
	int			pi_lastInnerVar;
	int			pi_lastOuterVar;
	int			pi_lastScanVar;
} ProjectionInfo;

/* ----------------
 *	  JunkFilter
 *
 *	  This class is used to store information regarding junk attributes.
 *	  A junk attribute is an attribute in a tuple that is needed only for
 *	  storing intermediate information in the executor, and does not belong
 *	  in emitted tuples.  For example, when we do an UPDATE query,
 *	  the planner adds a "junk" entry to the targetlist so that the tuples
 *	  returned to ExecutePlan() contain an extra attribute: the ctid of
 *	  the tuple to be updated.	This is needed to do the update, but we
 *	  don't want the ctid to be part of the stored new tuple!  So, we
 *	  apply a "junk filter" to remove the junk attributes and form the
 *	  real output tuple.  The junkfilter code also provides routines to
 *	  extract the values of the junk attribute(s) from the input tuple.
 *
 *	  targetList:		the original target list (including junk attributes).
 *	  cleanTupType:		the tuple descriptor for the "clean" tuple (with
 *						junk attributes removed).
 *	  cleanMap:			A map with the correspondence between the non-junk
 *						attribute numbers of the "original" tuple and the
 *						attribute numbers of the "clean" tuple.
 *	  resultSlot:		tuple slot used to hold cleaned tuple.
 *	  junkAttNo:		not used by junkfilter code.  Can be used by caller
 *						to remember the attno of a specific junk attribute
 *						(execMain.c stores the "ctid" attno here).
 * ----------------
 */
typedef struct JunkFilter
{
	NodeTag		type;
	List	   *jf_targetList;
	TupleDesc	jf_cleanTupType;
	AttrNumber *jf_cleanMap;
	TupleTableSlot *jf_resultSlot;
	AttrNumber	jf_junkAttNo;
} JunkFilter;

/* ----------------
 *	  ResultRelInfo information
 *
 *		Whenever we update an existing relation, we have to
 *		update indices on the relation, and perhaps also fire triggers.
 *		The ResultRelInfo class is used to hold all the information needed
 *		about a result relation, including indices.. -cim 10/15/89
 *
 *		RangeTableIndex			result relation's range table index
 *		RelationDesc			relation descriptor for result relation
 *		NumIndices				# of indices existing on result relation
 *		IndexRelationDescs		array of relation descriptors for indices
 *		IndexRelationInfo		array of key/attr info for indices
 *		TrigDesc				triggers to be fired, if any
 *		TrigFunctions			cached lookup info for trigger functions
 *		TrigWhenExprs			array of trigger WHEN expr states
 *		TrigInstrument			optional runtime measurements for triggers
 *		ConstraintExprs			array of constraint-checking expr states
 *		junkFilter				for removing junk attributes from tuples
 *		projectReturning		for computing a RETURNING list
 * ----------------
 */
typedef struct ResultRelInfo
{
	NodeTag		type;
	Index		ri_RangeTableIndex;
	Relation	ri_RelationDesc;
	int			ri_NumIndices;
	RelationPtr ri_IndexRelationDescs;
	IndexInfo **ri_IndexRelationInfo;
	TriggerDesc *ri_TrigDesc;
	FmgrInfo   *ri_TrigFunctions;
	List	  **ri_TrigWhenExprs;
	Instrumentation *ri_TrigInstrument;
	List	  **ri_ConstraintExprs;
	JunkFilter *ri_junkFilter;
	ProjectionInfo *ri_projectReturning;
} ResultRelInfo;

/* ----------------
 *	  EState information
 *
 * Master working state for an Executor invocation
 * ----------------
 */
typedef struct EState
{
	NodeTag		type;

	/* Basic state for all query types: */
	ScanDirection es_direction; /* current scan direction */
	Snapshot	es_snapshot;	/* time qual to use */
	Snapshot	es_crosscheck_snapshot; /* crosscheck time qual for RI */
	List	   *es_range_table; /* List of RangeTblEntry */
	PlannedStmt *es_plannedstmt;	/* link to top of plan tree */

	JunkFilter *es_junkFilter;	/* top-level junk filter, if any */

	/* If query can insert/delete tuples, the command ID to mark them with */
	CommandId	es_output_cid;

	/* Info about target table(s) for insert/update/delete queries: */
	ResultRelInfo *es_result_relations; /* array of ResultRelInfos */
	int			es_num_result_relations;		/* length of array */
	ResultRelInfo *es_result_relation_info;		/* currently active array elt */

	/* Stuff used for firing triggers: */
	List	   *es_trig_target_relations;		/* trigger-only ResultRelInfos */
	TupleTableSlot *es_trig_tuple_slot; /* for trigger output tuples */
	TupleTableSlot *es_trig_oldtup_slot;		/* for TriggerEnabled */
	TupleTableSlot *es_trig_newtup_slot;		/* for TriggerEnabled */

	/* Parameter info: */
	ParamListInfo es_param_list_info;	/* values of external params */
	ParamExecData *es_param_exec_vals;	/* values of internal params */

	/* Other working state: */
	MemoryContext es_query_cxt; /* per-query context in which EState lives */

	List	   *es_tupleTable;	/* List of TupleTableSlots */

	List	   *es_rowMarks;	/* List of ExecRowMarks */

	uint32		es_processed;	/* # of tuples processed */
	Oid			es_lastoid;		/* last oid processed (by INSERT) */

	int			es_top_eflags;	/* eflags passed to ExecutorStart */
	int			es_instrument;	/* OR of InstrumentOption flags */
	bool		es_finished;	/* true when ExecutorFinish is done */

	List	   *es_exprcontexts;	/* List of ExprContexts within EState */

	List	   *es_subplanstates;		/* List of PlanState for SubPlans */

	List	   *es_auxmodifytables;		/* List of secondary ModifyTableStates */

	/*
	 * this ExprContext is for per-output-tuple operations, such as constraint
	 * checks and index-value computations.  It will be reset for each output
	 * tuple.  Note that it will be created only if needed.
	 */
	ExprContext *es_per_tuple_exprcontext;

	/*
	 * These fields are for re-evaluating plan quals when an updated tuple is
	 * substituted in READ COMMITTED mode.	es_epqTuple[] contains tuples that
	 * scan plan nodes should return instead of whatever they'd normally
	 * return, or NULL if nothing to return; es_epqTupleSet[] is true if a
	 * particular array entry is valid; and es_epqScanDone[] is state to
	 * remember if the tuple has been returned already.  Arrays are of size
	 * list_length(es_range_table) and are indexed by scan node scanrelid - 1.
	 */
	HeapTuple  *es_epqTuple;	/* array of EPQ substitute tuples */
	bool	   *es_epqTupleSet; /* true if EPQ tuple is provided */
	bool	   *es_epqScanDone; /* true if EPQ tuple has been fetched */
} EState;


/*
 * ExecRowMark -
 *	   runtime representation of FOR UPDATE/SHARE clauses
 *
 * When doing UPDATE, DELETE, or SELECT FOR UPDATE/SHARE, we should have an
 * ExecRowMark for each non-target relation in the query (except inheritance
 * parent RTEs, which can be ignored at runtime).  See PlanRowMark for details
 * about most of the fields.  In addition to fields directly derived from
 * PlanRowMark, we store curCtid, which is used by the WHERE CURRENT OF code.
 *
 * EState->es_rowMarks is a list of these structs.
 */
typedef struct ExecRowMark
{
	Relation	relation;		/* opened and suitably locked relation */
	Index		rti;			/* its range table index */
	Index		prti;			/* parent range table index, if child */
	Index		rowmarkId;		/* unique identifier for resjunk columns */
	RowMarkType markType;		/* see enum in nodes/plannodes.h */
	bool		noWait;			/* NOWAIT option */
	ItemPointerData curCtid;	/* ctid of currently locked tuple, if any */
} ExecRowMark;

/*
 * ExecAuxRowMark -
 *	   additional runtime representation of FOR UPDATE/SHARE clauses
 *
 * Each LockRows and ModifyTable node keeps a list of the rowmarks it needs to
 * deal with.  In addition to a pointer to the related entry in es_rowMarks,
 * this struct carries the column number(s) of the resjunk columns associated
 * with the rowmark (see comments for PlanRowMark for more detail).  In the
 * case of ModifyTable, there has to be a separate ExecAuxRowMark list for
 * each child plan, because the resjunk columns could be at different physical
 * column positions in different subplans.
 */
typedef struct ExecAuxRowMark
{
	ExecRowMark *rowmark;		/* related entry in es_rowMarks */
	AttrNumber	ctidAttNo;		/* resno of ctid junk attribute, if any */
	AttrNumber	toidAttNo;		/* resno of tableoid junk attribute, if any */
	AttrNumber	wholeAttNo;		/* resno of whole-row junk attribute, if any */
} ExecAuxRowMark;


/* ----------------------------------------------------------------
 *				 Tuple Hash Tables
 *
 * All-in-memory tuple hash tables are used for a number of purposes.
 *
 * Note: tab_hash_funcs are for the key datatype(s) stored in the table,
 * and tab_eq_funcs are non-cross-type equality operators for those types.
 * Normally these are the only functions used, but FindTupleHashEntry()
 * supports searching a hashtable using cross-data-type hashing.  For that,
 * the caller must supply hash functions for the LHS datatype as well as
 * the cross-type equality operators to use.  in_hash_funcs and cur_eq_funcs
 * are set to point to the caller's function arrays while doing such a search.
 * During LookupTupleHashEntry(), they point to tab_hash_funcs and
 * tab_eq_funcs respectively.
 * ----------------------------------------------------------------
 */
typedef struct TupleHashEntryData *TupleHashEntry;
typedef struct TupleHashTableData *TupleHashTable;

typedef struct TupleHashEntryData
{
	/* firstTuple must be the first field in this struct! */
	MinimalTuple firstTuple;	/* copy of first tuple in this group */
	/* there may be additional data beyond the end of this struct */
} TupleHashEntryData;			/* VARIABLE LENGTH STRUCT */

typedef struct TupleHashTableData
{
	HTAB	   *hashtab;		/* underlying dynahash table */
	int			numCols;		/* number of columns in lookup key */
	AttrNumber *keyColIdx;		/* attr numbers of key columns */
	FmgrInfo   *tab_hash_funcs; /* hash functions for table datatype(s) */
	FmgrInfo   *tab_eq_funcs;	/* equality functions for table datatype(s) */
	MemoryContext tablecxt;		/* memory context containing table */
	MemoryContext tempcxt;		/* context for function evaluations */
	Size		entrysize;		/* actual size to make each hash entry */
	TupleTableSlot *tableslot;	/* slot for referencing table entries */
	/* The following fields are set transiently for each table search: */
	TupleTableSlot *inputslot;	/* current input tuple's slot */
	FmgrInfo   *in_hash_funcs;	/* hash functions for input datatype(s) */
	FmgrInfo   *cur_eq_funcs;	/* equality functions for input vs. table */
}	TupleHashTableData;

typedef HASH_SEQ_STATUS TupleHashIterator;

/*
 * Use InitTupleHashIterator/TermTupleHashIterator for a read/write scan.
 * Use ResetTupleHashIterator if the table can be frozen (in this case no
 * explicit scan termination is needed).
 */
#define InitTupleHashIterator(htable, iter) \
	hash_seq_init(iter, (htable)->hashtab)
#define TermTupleHashIterator(iter) \
	hash_seq_term(iter)
#define ResetTupleHashIterator(htable, iter) \
	do { \
		hash_freeze((htable)->hashtab); \
		hash_seq_init(iter, (htable)->hashtab); \
	} while (0)
#define ScanTupleHashTable(iter) \
	((TupleHashEntry) hash_seq_search(iter))


/* ----------------------------------------------------------------
 *				 Expression State Trees
 *
 * Each executable expression tree has a parallel ExprState tree.
 *
 * Unlike PlanState, there is not an exact one-for-one correspondence between
 * ExprState node types and Expr node types.  Many Expr node types have no
 * need for node-type-specific run-time state, and so they can use plain
 * ExprState or GenericExprState as their associated ExprState node type.
 * ----------------------------------------------------------------
 */

/* ----------------
 *		ExprState node
 *
 * ExprState is the common superclass for all ExprState-type nodes.
 *
 * It can also be instantiated directly for leaf Expr nodes that need no
 * local run-time state (such as Var, Const, or Param).
 *
 * To save on dispatch overhead, each ExprState node contains a function
 * pointer to the routine to execute to evaluate the node.
 * ----------------
 */

typedef struct ExprState ExprState;

typedef Datum (*ExprStateEvalFunc) (ExprState *expression,
												ExprContext *econtext,
												bool *isNull,
												ExprDoneCond *isDone);

struct ExprState
{
	NodeTag		type;
	Expr	   *expr;			/* associated Expr node */
	ExprStateEvalFunc evalfunc; /* routine to run to execute node */
};

/* ----------------
 *		GenericExprState node
 *
 * This is used for Expr node types that need no local run-time state,
 * but have one child Expr node.
 * ----------------
 */
typedef struct GenericExprState
{
	ExprState	xprstate;
	ExprState  *arg;			/* state of my child node */
} GenericExprState;

/* ----------------
 *		AggrefExprState node
 * ----------------
 */
typedef struct AggrefExprState
{
	ExprState	xprstate;
	List	   *args;			/* states of argument expressions */
	int			aggno;			/* ID number for agg within its plan node */
} AggrefExprState;

/* ----------------
 *		WindowFuncExprState node
 * ----------------
 */
typedef struct WindowFuncExprState
{
	ExprState	xprstate;
	List	   *args;			/* states of argument expressions */
	int			wfuncno;		/* ID number for wfunc within its plan node */
} WindowFuncExprState;

/* ----------------
 *		ArrayRefExprState node
 *
 * Note: array types can be fixed-length (typlen > 0), but only when the
 * element type is itself fixed-length.  Otherwise they are varlena structures
 * and have typlen = -1.  In any case, an array type is never pass-by-value.
 * ----------------
 */
typedef struct ArrayRefExprState
{
	ExprState	xprstate;
	List	   *refupperindexpr;	/* states for child nodes */
	List	   *reflowerindexpr;
	ExprState  *refexpr;
	ExprState  *refassgnexpr;
	int16		refattrlength;	/* typlen of array type */
	int16		refelemlength;	/* typlen of the array element type */
	bool		refelembyval;	/* is the element type pass-by-value? */
	char		refelemalign;	/* typalign of the element type */
} ArrayRefExprState;

/* ----------------
 *		FuncExprState node
 *
 * Although named for FuncExpr, this is also used for OpExpr, DistinctExpr,
 * and NullIf nodes; be careful to check what xprstate.expr is actually
 * pointing at!
 * ----------------
 */
typedef struct FuncExprState
{
	ExprState	xprstate;
	List	   *args;			/* states of argument expressions */

	/*
	 * Function manager's lookup info for the target function.  If func.fn_oid
	 * is InvalidOid, we haven't initialized it yet (nor any of the following
	 * fields).
	 */
	FmgrInfo	func;

	/*
	 * For a set-returning function (SRF) that returns a tuplestore, we keep
	 * the tuplestore here and dole out the result rows one at a time. The
	 * slot holds the row currently being returned.
	 */
	Tuplestorestate *funcResultStore;
	TupleTableSlot *funcResultSlot;

	/*
	 * In some cases we need to compute a tuple descriptor for the function's
	 * output.	If so, it's stored here.
	 */
	TupleDesc	funcResultDesc;
	bool		funcReturnsTuple;		/* valid when funcResultDesc isn't
										 * NULL */

	/*
	 * setArgsValid is true when we are evaluating a set-returning function
	 * that uses value-per-call mode and we are in the middle of a call
	 * series; we want to pass the same argument values to the function again
	 * (and again, until it returns ExprEndResult).  This indicates that
	 * fcinfo_data already contains valid argument data.
	 */
	bool		setArgsValid;

	/*
	 * Flag to remember whether we found a set-valued argument to the
	 * function. This causes the function result to be a set as well. Valid
	 * only when setArgsValid is true or funcResultStore isn't NULL.
	 */
	bool		setHasSetArg;	/* some argument returns a set */

	/*
	 * Flag to remember whether we have registered a shutdown callback for
	 * this FuncExprState.	We do so only if funcResultStore or setArgsValid
	 * has been set at least once (since all the callback is for is to release
	 * the tuplestore or clear setArgsValid).
	 */
	bool		shutdown_reg;	/* a shutdown callback is registered */

	/*
	 * Call parameter structure for the function.  This has been initialized
	 * (by InitFunctionCallInfoData) if func.fn_oid is valid.  It also saves
	 * argument values between calls, when setArgsValid is true.
	 */
	FunctionCallInfoData fcinfo_data;
} FuncExprState;

/* ----------------
 *		ScalarArrayOpExprState node
 *
 * This is a FuncExprState plus some additional data.
 * ----------------
 */
typedef struct ScalarArrayOpExprState
{
	FuncExprState fxprstate;
	/* Cached info about array element type */
	Oid			element_type;
	int16		typlen;
	bool		typbyval;
	char		typalign;
} ScalarArrayOpExprState;

/* ----------------
 *		BoolExprState node
 * ----------------
 */
typedef struct BoolExprState
{
	ExprState	xprstate;
	List	   *args;			/* states of argument expression(s) */
} BoolExprState;

/* ----------------
 *		SubPlanState node
 * ----------------
 */
typedef struct SubPlanState
{
	ExprState	xprstate;
	struct PlanState *planstate;	/* subselect plan's state tree */
	ExprState  *testexpr;		/* state of combining expression */
	List	   *args;			/* states of argument expression(s) */
	HeapTuple	curTuple;		/* copy of most recent tuple from subplan */
	Datum		curArray;		/* most recent array from ARRAY() subplan */
	/* these are used when hashing the subselect's output: */
	ProjectionInfo *projLeft;	/* for projecting lefthand exprs */
	ProjectionInfo *projRight;	/* for projecting subselect output */
	TupleHashTable hashtable;	/* hash table for no-nulls subselect rows */
	TupleHashTable hashnulls;	/* hash table for rows with null(s) */
	bool		havehashrows;	/* TRUE if hashtable is not empty */
	bool		havenullrows;	/* TRUE if hashnulls is not empty */
	MemoryContext hashtablecxt; /* memory context containing hash tables */
	MemoryContext hashtempcxt;	/* temp memory context for hash tables */
	ExprContext *innerecontext; /* econtext for computing inner tuples */
	AttrNumber *keyColIdx;		/* control data for hash tables */
	FmgrInfo   *tab_hash_funcs; /* hash functions for table datatype(s) */
	FmgrInfo   *tab_eq_funcs;	/* equality functions for table datatype(s) */
	FmgrInfo   *lhs_hash_funcs; /* hash functions for lefthand datatype(s) */
	FmgrInfo   *cur_eq_funcs;	/* equality functions for LHS vs. table */
} SubPlanState;

/* ----------------
 *		AlternativeSubPlanState node
 * ----------------
 */
typedef struct AlternativeSubPlanState
{
	ExprState	xprstate;
	List	   *subplans;		/* states of alternative subplans */
	int			active;			/* list index of the one we're using */
} AlternativeSubPlanState;

/* ----------------
 *		FieldSelectState node
 * ----------------
 */
typedef struct FieldSelectState
{
	ExprState	xprstate;
	ExprState  *arg;			/* input expression */
	TupleDesc	argdesc;		/* tupdesc for most recent input */
} FieldSelectState;

/* ----------------
 *		FieldStoreState node
 * ----------------
 */
typedef struct FieldStoreState
{
	ExprState	xprstate;
	ExprState  *arg;			/* input tuple value */
	List	   *newvals;		/* new value(s) for field(s) */
	TupleDesc	argdesc;		/* tupdesc for most recent input */
} FieldStoreState;

/* ----------------
 *		CoerceViaIOState node
 * ----------------
 */
typedef struct CoerceViaIOState
{
	ExprState	xprstate;
	ExprState  *arg;			/* input expression */
	FmgrInfo	outfunc;		/* lookup info for source output function */
	FmgrInfo	infunc;			/* lookup info for result input function */
	Oid			intypioparam;	/* argument needed for input function */
} CoerceViaIOState;

/* ----------------
 *		ArrayCoerceExprState node
 * ----------------
 */
typedef struct ArrayCoerceExprState
{
	ExprState	xprstate;
	ExprState  *arg;			/* input array value */
	Oid			resultelemtype; /* element type of result array */
	FmgrInfo	elemfunc;		/* lookup info for element coercion function */
	/* use struct pointer to avoid including array.h here */
	struct ArrayMapState *amstate;		/* workspace for array_map */
} ArrayCoerceExprState;

/* ----------------
 *		ConvertRowtypeExprState node
 * ----------------
 */
typedef struct ConvertRowtypeExprState
{
	ExprState	xprstate;
	ExprState  *arg;			/* input tuple value */
	TupleDesc	indesc;			/* tupdesc for source rowtype */
	TupleDesc	outdesc;		/* tupdesc for result rowtype */
	/* use "struct" so we needn't include tupconvert.h here */
	struct TupleConversionMap *map;
	bool		initialized;
} ConvertRowtypeExprState;

/* ----------------
 *		CaseExprState node
 * ----------------
 */
typedef struct CaseExprState
{
	ExprState	xprstate;
	ExprState  *arg;			/* implicit equality comparison argument */
	List	   *args;			/* the arguments (list of WHEN clauses) */
	ExprState  *defresult;		/* the default result (ELSE clause) */
} CaseExprState;

/* ----------------
 *		CaseWhenState node
 * ----------------
 */
typedef struct CaseWhenState
{
	ExprState	xprstate;
	ExprState  *expr;			/* condition expression */
	ExprState  *result;			/* substitution result */
} CaseWhenState;

/* ----------------
 *		ArrayExprState node
 *
 * Note: ARRAY[] expressions always produce varlena arrays, never fixed-length
 * arrays.
 * ----------------
 */
typedef struct ArrayExprState
{
	ExprState	xprstate;
	List	   *elements;		/* states for child nodes */
	int16		elemlength;		/* typlen of the array element type */
	bool		elembyval;		/* is the element type pass-by-value? */
	char		elemalign;		/* typalign of the element type */
} ArrayExprState;

/* ----------------
 *		RowExprState node
 * ----------------
 */
typedef struct RowExprState
{
	ExprState	xprstate;
	List	   *args;			/* the arguments */
	TupleDesc	tupdesc;		/* descriptor for result tuples */
} RowExprState;

/* ----------------
 *		RowCompareExprState node
 * ----------------
 */
typedef struct RowCompareExprState
{
	ExprState	xprstate;
	List	   *largs;			/* the left-hand input arguments */
	List	   *rargs;			/* the right-hand input arguments */
	FmgrInfo   *funcs;			/* array of comparison function info */
	Oid		   *collations;		/* array of collations to use */
} 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;

/* ----------------
 *		XmlExprState node
 * ----------------
 */
typedef struct XmlExprState
{
	ExprState	xprstate;
	List	   *named_args;		/* ExprStates for named arguments */
	List	   *args;			/* ExprStates for other arguments */
} XmlExprState;

/* ----------------
 *		NullTestState node
 * ----------------
 */
typedef struct NullTestState
{
	ExprState	xprstate;
	ExprState  *arg;			/* input expression */
	/* used only if input is of composite type: */
	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, states of individual
								 * nodes point to one EState for the whole
								 * top-level plan */

	Instrumentation *instrument;	/* Optional runtime stats for this 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_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;