text: /*-------------------------------------------------------------------------
   *
   * execnodes.h
   *	  definitions for executor state nodes
   *
   *
   * Portions Copyright (c) 1996-2019, 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/tupconvert.h"
  #include "executor/instrument.h"
  #include "fmgr.h"
  #include "lib/pairingheap.h"
  #include "nodes/params.h"
  #include "nodes/plannodes.h"
  #include "partitioning/partdefs.h"
  #include "utils/hsearch.h"
  #include "utils/queryenvironment.h"
  #include "utils/reltrigger.h"
  #include "utils/sharedtuplestore.h"
  #include "utils/snapshot.h"
  #include "utils/sortsupport.h"
  #include "utils/tuplestore.h"
  #include "utils/tuplesort.h"
  #include "nodes/tidbitmap.h"
  #include "storage/condition_variable.h"
  
  
  struct PlanState;				/* forward references in this file */
  struct PartitionRoutingInfo;
  struct ParallelHashJoinState;
  struct ExecRowMark;
  struct ExprState;
  struct ExprContext;
  struct RangeTblEntry;			/* avoid including parsenodes.h here */
  struct ExprEvalStep;			/* avoid including execExpr.h everywhere */
  struct CopyMultiInsertBuffer;
  
  
  /* ----------------
   *		ExprState node
   *
   * ExprState is the top-level node for expression evaluation.
   * It contains instructions (in ->steps) to evaluate the expression.
   * ----------------
   */
  typedef Datum (*ExprStateEvalFunc) (struct ExprState *expression,
  									struct ExprContext *econtext,
  									bool *isNull);
  
  /* Bits in ExprState->flags (see also execExpr.h for private flag bits): */
  /* expression is for use with ExecQual() */
  #define EEO_FLAG_IS_QUAL					(1 << 0)
  
  typedef struct ExprState
  {
  	NodeTag		tag;
  
  	uint8		flags;			/* bitmask of EEO_FLAG_* bits, see above */
  
  	/*
  	 * Storage for result value of a scalar expression, or for individual
  	 * column results within expressions built by ExecBuildProjectionInfo().
  	 */
  #define FIELDNO_EXPRSTATE_RESNULL 2
  	bool		resnull;
  #define FIELDNO_EXPRSTATE_RESVALUE 3
  	Datum		resvalue;
  
  	/*
  	 * If projecting a tuple result, this slot holds the result; else NULL.
  	 */
  #define FIELDNO_EXPRSTATE_RESULTSLOT 4
  	TupleTableSlot *resultslot;
  
  	/*
  	 * Instructions to compute expression's return value.
  	 */
  	struct ExprEvalStep *steps;
  
  	/*
  	 * Function that actually evaluates the expression.  This can be set to
  	 * different values depending on the complexity of the expression.
  	 */
  	ExprStateEvalFunc evalfunc;
  
  	/* original expression tree, for debugging only */
  	Expr	   *expr;
  
  	/* private state for an evalfunc */
  	void	   *evalfunc_private;
  
  	/*
  	 * XXX: following fields only needed during "compilation" (ExecInitExpr);
  	 * could be thrown away afterwards.
  	 */
  
  	int			steps_len;		/* number of steps currently */
  	int			steps_alloc;	/* allocated length of steps array */
  
  	struct PlanState *parent;	/* parent PlanState node, if any */
  	ParamListInfo ext_params;	/* for compiling PARAM_EXTERN nodes */
  
  	Datum	   *innermost_caseval;
  	bool	   *innermost_casenull;
  
  	Datum	   *innermost_domainval;
  	bool	   *innermost_domainnull;
  } ExprState;
  
  
  /* ----------------
   *	  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		total number of columns in this index
   *		NumIndexKeyAttrs	number of key columns in index
   *		IndexAttrNumbers	underlying-rel attribute numbers used as keys
   *							(zeroes indicate expressions). It also contains
   * 							info about included columns.
   *		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
   *		UniqueOps			These are like Exclusion*, but for unique indexes
   *		UniqueProcs
   *		UniqueStrats
   *		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?
   *		ParallelWorkers		# of workers requested (excludes leader)
   *		Am					Oid of index AM
   *		AmCache				private cache area for index AM
   *		Context				memory context holding this IndexInfo
   *
   * ii_Concurrent, ii_BrokenHotChain, and ii_ParallelWorkers are used only
   * during index build; they're conventionally zeroed otherwise.
   * ----------------
   */
  typedef struct IndexInfo
  {
  	NodeTag		type;
  	int			ii_NumIndexAttrs;	/* total number of columns in index */
  	int			ii_NumIndexKeyAttrs;	/* number of key columns in index */
  	AttrNumber	ii_IndexAttrNumbers[INDEX_MAX_KEYS];
  	List	   *ii_Expressions; /* list of Expr */
  	List	   *ii_ExpressionsState;	/* list of ExprState */
  	List	   *ii_Predicate;	/* list of Expr */
  	ExprState  *ii_PredicateState;
  	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 */
  	Oid		   *ii_UniqueOps;	/* array with one entry per column */
  	Oid		   *ii_UniqueProcs; /* array with one entry per column */
  	uint16	   *ii_UniqueStrats;	/* array with one entry per column */
  	bool		ii_Unique;
  	bool		ii_ReadyForInserts;
  	bool		ii_Concurrent;
  	bool		ii_BrokenHotChain;
  	int			ii_ParallelWorkers;
  	Oid			ii_Am;
  	void	   *ii_AmCache;
  	MemoryContext ii_Context;
  } 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 */
  #define FIELDNO_EXPRCONTEXT_SCANTUPLE 1
  	TupleTableSlot *ecxt_scantuple;
  #define FIELDNO_EXPRCONTEXT_INNERTUPLE 2
  	TupleTableSlot *ecxt_innertuple;
  #define FIELDNO_EXPRCONTEXT_OUTERTUPLE 3
  	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.
  	 */
  #define FIELDNO_EXPRCONTEXT_AGGVALUES 8
  	Datum	   *ecxt_aggvalues; /* precomputed values for aggs/windowfuncs */
  #define FIELDNO_EXPRCONTEXT_AGGNULLS 9
  	bool	   *ecxt_aggnulls;	/* null flags for aggs/windowfuncs */
  
  	/* Value to substitute for CaseTestExpr nodes in expression */
  #define FIELDNO_EXPRCONTEXT_CASEDATUM 10
  	Datum		caseValue_datum;
  #define FIELDNO_EXPRCONTEXT_CASENULL 11
  	bool		caseValue_isNull;
  
  	/* Value to substitute for CoerceToDomainValue nodes in expression */
  #define FIELDNO_EXPRCONTEXT_DOMAINDATUM 12
  	Datum		domainValue_datum;
  #define FIELDNO_EXPRCONTEXT_DOMAINNULL 13
  	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 or rescanned */
  	ExprContext_CB *ecxt_callbacks;
  } ExprContext;
  
  /*
   * Set-result status used when evaluating functions potentially returning a
   * set.
   */
  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.
   *
   *		The target tuple slot is kept in ProjectionInfo->pi_state.resultslot.
   *		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!
   * ----------------
   */
  typedef struct ProjectionInfo
  {
  	NodeTag		type;
  	/* instructions to evaluate projection */
  	ExprState	pi_state;
  	/* expression context in which to evaluate expression */
  	ExprContext *pi_exprContext;
  } 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
   *						(nodeModifyTable.c keeps the "ctid" or "wholerow"
   *						attno here).
   * ----------------
   */
  typedef struct JunkFilter
  {
  	NodeTag		type;
  	List	   *jf_targetList;
  	TupleDesc	jf_cleanTupType;
  	AttrNumber *jf_cleanMap;
  	TupleTableSlot *jf_resultSlot;
  	AttrNumber	jf_junkAttNo;
  } JunkFilter;
  
  /*
   * OnConflictSetState
   *
   * Executor state of an ON CONFLICT DO UPDATE operation.
   */
  typedef struct OnConflictSetState
  {
  	NodeTag		type;
  
  	TupleTableSlot *oc_Existing;	/* slot to store existing target tuple in */
  	TupleTableSlot *oc_ProjSlot;	/* CONFLICT ... SET ... projection target */
  	ProjectionInfo *oc_ProjInfo;	/* for ON CONFLICT DO UPDATE SET */
  	ExprState  *oc_WhereClause; /* state for the WHERE clause */
  } OnConflictSetState;
  
  /*
   * ResultRelInfo
   *
   * Whenever we update an existing relation, we have to update indexes on the
   * relation, and perhaps also fire triggers.  ResultRelInfo holds all the
   * information needed about a result relation, including indexes.
   *
   * Normally, a ResultRelInfo refers to a table that is in the query's
   * range table; then ri_RangeTableIndex is the RT index and ri_RelationDesc
   * is just a copy of the relevant es_relations[] entry.  But sometimes,
   * in ResultRelInfos used only for triggers, ri_RangeTableIndex is zero
   * and ri_RelationDesc is a separately-opened relcache pointer that needs
   * to be separately closed.  See ExecGetTriggerResultRel.
   */
  typedef struct ResultRelInfo
  {
  	NodeTag		type;
  
  	/* result relation's range table index, or 0 if not in range table */
  	Index		ri_RangeTableIndex;
  
  	/* relation descriptor for result relation */
  	Relation	ri_RelationDesc;
  
  	/* # of indices existing on result relation */
  	int			ri_NumIndices;
  
  	/* array of relation descriptors for indices */
  	RelationPtr ri_IndexRelationDescs;
  
  	/* array of key/attr info for indices */
  	IndexInfo **ri_IndexRelationInfo;
  
  	/* triggers to be fired, if any */
  	TriggerDesc *ri_TrigDesc;
  
  	/* cached lookup info for trigger functions */
  	FmgrInfo   *ri_TrigFunctions;
  
  	/* array of trigger WHEN expr states */
  	ExprState **ri_TrigWhenExprs;
  
  	/* optional runtime measurements for triggers */
  	Instrumentation *ri_TrigInstrument;
  
  	/* On-demand created slots for triggers / returning processing */
  	TupleTableSlot *ri_ReturningSlot;	/* for trigger output tuples */
  	TupleTableSlot *ri_TrigOldSlot; /* for a trigger's old tuple */
  	TupleTableSlot *ri_TrigNewSlot; /* for a trigger's new tuple */
  
  	/* FDW callback functions, if foreign table */
  	struct FdwRoutine *ri_FdwRoutine;
  
  	/* available to save private state of FDW */
  	void	   *ri_FdwState;
  
  	/* true when modifying foreign table directly */
  	bool		ri_usesFdwDirectModify;
  
  	/* list of WithCheckOption's to be checked */
  	List	   *ri_WithCheckOptions;
  
  	/* list of WithCheckOption expr states */
  	List	   *ri_WithCheckOptionExprs;
  
  	/* array of constraint-checking expr states */
  	ExprState **ri_ConstraintExprs;
  
  	/* array of stored generated columns expr states */
  	ExprState **ri_GeneratedExprs;
  
  	/* for removing junk attributes from tuples */
  	JunkFilter *ri_junkFilter;
  
  	/* list of RETURNING expressions */
  	List	   *ri_returningList;
  
  	/* for computing a RETURNING list */
  	ProjectionInfo *ri_projectReturning;
  
  	/* list of arbiter indexes to use to check conflicts */
  	List	   *ri_onConflictArbiterIndexes;
  
  	/* ON CONFLICT evaluation state */
  	OnConflictSetState *ri_onConflict;
  
  	/* partition check expression */
  	List	   *ri_PartitionCheck;
  
  	/* partition check expression state */
  	ExprState  *ri_PartitionCheckExpr;
  
  	/* relation descriptor for root partitioned table */
  	Relation	ri_PartitionRoot;
  
  	/* Additional information specific to partition tuple routing */
  	struct PartitionRoutingInfo *ri_PartitionInfo;
  
  	/* For use by copy.c when performing multi-inserts */
  	struct CopyMultiInsertBuffer *ri_CopyMultiInsertBuffer;
  } 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 */
  	Index		es_range_table_size;	/* size of the range table arrays */
  	Relation   *es_relations;	/* Array of per-range-table-entry Relation
  								 * pointers, or NULL if not yet opened */
  	struct ExecRowMark **es_rowmarks;	/* Array of per-range-table-entry
  										 * ExecRowMarks, or NULL if none */
  	PlannedStmt *es_plannedstmt;	/* link to top of plan tree */
  	const char *es_sourceText;	/* Source text from QueryDesc */
  
  	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 */
  
  	/*
  	 * Info about the partition root table(s) for insert/update/delete queries
  	 * targeting partitioned tables.  Only leaf partitions are mentioned in
  	 * es_result_relations, but we need access to the roots for firing
  	 * triggers and for runtime tuple routing.
  	 */
  	ResultRelInfo *es_root_result_relations;	/* array of ResultRelInfos */
  	int			es_num_root_result_relations;	/* length of the array */
  	PartitionDirectory es_partition_directory;	/* for PartitionDesc lookup */
  
  	/*
  	 * The following list contains ResultRelInfos created by the tuple routing
  	 * code for partitions that don't already have one.
  	 */
  	List	   *es_tuple_routing_result_relations;
  
  	/* Stuff used for firing triggers: */
  	List	   *es_trig_target_relations;	/* trigger-only ResultRelInfos */
  
  	/* Parameter info: */
  	ParamListInfo es_param_list_info;	/* values of external params */
  	ParamExecData *es_param_exec_vals;	/* values of internal params */
  
  	QueryEnvironment *es_queryEnv;	/* query environment */
  
  	/* Other working state: */
  	MemoryContext es_query_cxt; /* per-query context in which EState lives */
  
  	List	   *es_tupleTable;	/* List of TupleTableSlots */
  
  	uint64		es_processed;	/* # of tuples processed */
  
  	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;
  
  	/*
  	 * If not NULL, this is an EPQState's EState. This is a field in EState
  	 * both to allow EvalPlanQual aware executor nodes to detect that they
  	 * need to perform EPQ related work, and to provide necessary information
  	 * to do so.
  	 */
  	struct EPQState *es_epq_active;
  
  	bool		es_use_parallel_mode;	/* can we use parallel workers? */
  
  	/* The per-query shared memory area to use for parallel execution. */
  	struct dsa_area *es_query_dsa;
  
  	/*
  	 * JIT information. es_jit_flags indicates whether JIT should be performed
  	 * and with which options.  es_jit is created on-demand when JITing is
  	 * performed.
  	 *
  	 * es_jit_worker_instr is the combined, on demand allocated,
  	 * instrumentation from all workers. The leader's instrumentation is kept
  	 * separate, and is combined on demand by ExplainPrintJITSummary().
  	 */
  	int			es_jit_flags;
  	struct JitContext *es_jit;
  	struct JitInstrumentation *es_jit_worker_instr;
  } EState;
  
  
  /*
   * ExecRowMark -
   *	   runtime representation of FOR [KEY] UPDATE/SHARE clauses
   *
   * When doing UPDATE, DELETE, or SELECT FOR [KEY] UPDATE/SHARE, we will have an
   * ExecRowMark for each non-target relation in the query (except inheritance
   * parent RTEs, which can be ignored at runtime).  Virtual relations such as
   * subqueries-in-FROM will have an ExecRowMark with relation == NULL.  See
   * PlanRowMark for details about most of the fields.  In addition to fields
   * directly derived from PlanRowMark, we store an activity flag (to denote
   * inactive children of inheritance trees), curCtid, which is used by the
   * WHERE CURRENT OF code, and ermExtra, which is available for use by the plan
   * node that sources the relation (e.g., for a foreign table the FDW can use
   * ermExtra to hold information).
   *
   * EState->es_rowmarks is an array of these structs, indexed by RT index,
   * with NULLs for irrelevant RT indexes.  es_rowmarks itself is NULL if
   * there are no rowmarks.
   */
  typedef struct ExecRowMark
  {
  	Relation	relation;		/* opened and suitably locked relation */
  	Oid			relid;			/* its OID (or InvalidOid, if subquery) */
  	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 */
  	LockClauseStrength strength;	/* LockingClause's strength, or LCS_NONE */
  	LockWaitPolicy waitPolicy;	/* NOWAIT and SKIP LOCKED */
  	bool		ermActive;		/* is this mark relevant for current tuple? */
  	ItemPointerData curCtid;	/* ctid of currently locked tuple, if any */
  	void	   *ermExtra;		/* available for use by relation source node */
  } ExecRowMark;
  
  /*
   * ExecAuxRowMark -
   *	   additional runtime representation of FOR [KEY] 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_func
   * 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_func respectively.
   * ----------------------------------------------------------------
   */
  typedef struct TupleHashEntryData *TupleHashEntry;
  typedef struct TupleHashTableData *TupleHashTable;
  
  typedef struct TupleHashEntryData
  {
  	MinimalTuple firstTuple;	/* copy of first tuple in this group */
  	void	   *additional;		/* user data */
  	uint32		status;			/* hash status */
  	uint32		hash;			/* hash value (cached) */
  } TupleHashEntryData;
  
  /* define parameters necessary to generate the tuple hash table interface */
  #define SH_PREFIX tuplehash
  #define SH_ELEMENT_TYPE TupleHashEntryData
  #define SH_KEY_TYPE MinimalTuple
  #define SH_SCOPE extern
  #define SH_DECLARE
  #include "lib/simplehash.h"
  
  typedef struct TupleHashTableData
  {
  	tuplehash_hash *hashtab;	/* underlying hash 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) */
  	ExprState  *tab_eq_func;	/* comparator for table datatype(s) */
  	Oid		   *tab_collations; /* collations for hash and comparison */
  	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) */
  	ExprState  *cur_eq_func;	/* comparator for input vs. table */
  	uint32		hash_iv;		/* hash-function IV */
  	ExprContext *exprcontext;	/* expression context */
  }			TupleHashTableData;
  
  typedef tuplehash_iterator 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) \
  	tuplehash_start_iterate(htable->hashtab, iter)
  #define TermTupleHashIterator(iter) \
  	((void) 0)
  #define ResetTupleHashIterator(htable, iter) \
  	InitTupleHashIterator(htable, iter)
  #define ScanTupleHashTable(htable, iter) \
  	tuplehash_iterate(htable->hashtab, iter)
  
  
  /* ----------------------------------------------------------------
   *				 Expression State Nodes
   *
   * Formerly, there was a separate executor expression state node corresponding
   * to each node in a planned expression tree.  That's no longer the case; for
   * common expression node types, all the execution info is embedded into
   * step(s) in a single ExprState node.  But we still have a few executor state
   * node types for selected expression node types, mostly those in which info
   * has to be shared with other parts of the execution state tree.
   * ----------------------------------------------------------------
   */
  
  /* ----------------
   *		AggrefExprState node
   * ----------------
   */
  typedef struct AggrefExprState
  {
  	NodeTag		type;
  	Aggref	   *aggref;			/* expression plan node */
  	int			aggno;			/* ID number for agg within its plan node */
  } AggrefExprState;
  
  /* ----------------
   *		WindowFuncExprState node
   * ----------------
   */
  typedef struct WindowFuncExprState
  {
  	NodeTag		type;
  	WindowFunc *wfunc;			/* expression plan node */
  	List	   *args;			/* ExprStates for argument expressions */
  	ExprState  *aggfilter;		/* FILTER expression */
  	int			wfuncno;		/* ID number for wfunc within its plan node */
  } WindowFuncExprState;
  
  
  /* ----------------
   *		SetExprState node
   *
   * State for evaluating a potentially set-returning expression (like FuncExpr
   * or OpExpr).  In some cases, like some of the expressions in ROWS FROM(...)
   * the expression might not be a SRF, but nonetheless it uses the same
   * machinery as SRFs; it will be treated as a SRF returning a single row.
   * ----------------
   */
  typedef struct SetExprState
  {
  	NodeTag		type;
  	Expr	   *expr;			/* expression plan node */
  	List	   *args;			/* ExprStates for argument expressions */
  
  	/*
  	 * In ROWS FROM, functions can be inlined, removing the FuncExpr normally
  	 * inside.  In such a case this is the compiled expression (which cannot
  	 * return a set), which'll be evaluated using regular ExecEvalExpr().
  	 */
  	ExprState  *elidedFuncState;
  
  	/*
  	 * 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, except funcReturnsSet).
  	 */
  	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 */
  
  	/*
  	 * Remember whether the function is declared to return a set.  This is set
  	 * by ExecInitExpr, and is valid even before the FmgrInfo is set up.
  	 */
  	bool		funcReturnsSet;
  
  	/*
  	 * 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 have registered a shutdown callback for
  	 * this SetExprState.  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.
  	 */
  	FunctionCallInfo fcinfo;
  } SetExprState;
  
  /* ----------------
   *		SubPlanState node
   * ----------------
   */
  typedef struct SubPlanState
  {
  	NodeTag		type;
  	SubPlan    *subplan;		/* expression plan node */
  	struct PlanState *planstate;	/* subselect plan's state tree */
  	struct PlanState *parent;	/* parent plan node'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: */
  	TupleDesc	descRight;		/* subselect desc after projection */
  	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 */
  	Oid		   *tab_eq_funcoids;	/* equality func oids for table
  									 * datatype(s) */
  	Oid		   *tab_collations; /* collations for hash and comparison */
  	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 */
  	ExprState  *cur_eq_comp;	/* equality comparator for LHS vs. table */
  } SubPlanState;
  
  /* ----------------
   *		AlternativeSubPlanState node
   * ----------------
   */
  typedef struct AlternativeSubPlanState
  {
  	NodeTag		type;
  	AlternativeSubPlan *subplan;	/* expression plan node */
  	List	   *subplans;		/* SubPlanStates of alternative subplans */
  	int			active;			/* list index of the one we're using */
  } AlternativeSubPlanState;
  
  /*
   * DomainConstraintState - one item to check during CoerceToDomain
   *
   * Note: we consider this to be part of an ExprState tree, so we give it
   * a name following the xxxState convention.  But there's no directly
   * associated plan-tree node.
   */
  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) */
  	Expr	   *check_expr;		/* for CHECK, a boolean expression */
  	ExprState  *check_exprstate;	/* check_expr's eval state, or NULL */
  } DomainConstraintState;
  
  
  /* ----------------------------------------------------------------
   *				 Executor State Trees
   *
   * An executing query has a PlanState tree paralleling the Plan tree
   * that describes the plan.
   * ----------------------------------------------------------------
   */
  
  /* ----------------
   *	 ExecProcNodeMtd
   *
   * This is the method called by ExecProcNode to return the next tuple
   * from an executor node.  It returns NULL, or an empty TupleTableSlot,
   * if no more tuples are available.
   * ----------------
   */
  typedef TupleTableSlot *(*ExecProcNodeMtd) (struct PlanState *pstate);
  
  /* ----------------
   *		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 */
  
  	ExecProcNodeMtd ExecProcNode;	/* function to return next tuple */
  	ExecProcNodeMtd ExecProcNodeReal;	/* actual function, if above is a
  										 * wrapper */
  
  	Instrumentation *instrument;	/* Optional runtime stats for this node */
  	WorkerInstrumentation *worker_instrument;	/* per-worker instrumentation */
  
  	/* Per-worker JIT instrumentation */
  	struct SharedJitInstrumentation *worker_jit_instrument;
  
  	/*
  	 * 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).
  	 */
  	ExprState  *qual;			/* boolean qual condition */
  	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.
  	 */
  	TupleDesc	ps_ResultTupleDesc; /* node's return type */
  	TupleTableSlot *ps_ResultTupleSlot; /* slot for my result tuples */
  	ExprContext *ps_ExprContext;	/* node's expression-evaluation context */
  	ProjectionInfo *ps_ProjInfo;	/* info for doing tuple projection */
  
  	/*
  	 * Scanslot's descriptor if known. This is a bit of a hack, but otherwise
  	 * it's hard for expression compilation to optimize based on the
  	 * descriptor, without encoding knowledge about all executor nodes.
  	 */
  	TupleDesc	scandesc;
  
  	/*
  	 * Define the slot types for inner, outer and scanslots for expression
  	 * contexts with this state as a parent.  If *opsset is set, then
  	 * *opsfixed indicates whether *ops is guaranteed to be the type of slot
  	 * used. That means that every slot in the corresponding
  	 * ExprContext.ecxt_*tuple will point to a slot of that type, while
  	 * evaluating the expression.  If *opsfixed is false, but *ops is set,
  	 * that indicates the most likely type of slot.
  	 *
  	 * The scan* fields are set by ExecInitScanTupleSlot(). If that's not
  	 * called, nodes can initialize the fields themselves.
  	 *
  	 * If outer/inneropsset is false, the information is inferred on-demand
  	 * using ExecGetResultSlotOps() on ->righttree/lefttree, using the
  	 * corresponding node's resultops* fields.
  	 *
  	 * The result* fields are automatically set when ExecInitResultSlot is
  	 * used (be it directly or when the slot is created by
  	 * ExecAssignScanProjectionInfo() /
  	 * ExecConditionalAssignProjectionInfo()).  If no projection is necessary
  	 * ExecConditionalAssignProjectionInfo() defaults those fields to the scan
  	 * operations.
  	 */
  	const TupleTableSlotOps *scanops;
  	const TupleTableSlotOps *outerops;
  	const TupleTableSlotOps *innerops;
  	const TupleTableSlotOps *resultops;
  	bool		scanopsfixed;
  	bool		outeropsfixed;
  	bool		inneropsfixed;
  	bool		resultopsfixed;
  	bool		scanopsset;
  	bool		outeropsset;
  	bool		inneropsset;
  	bool		resultopsset;
  } PlanState;
  
  /* ----------------
   *	these 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)
  
  /* Macros for inline access to certain instrumentation counters */
  #define InstrCountTuples2(node, delta) \
  	do { \
  		if (((PlanState *)(node))->instrument) \
  			((PlanState *)(node))->instrument->ntuples2 += (delta); \
  	} while (0)
  #define InstrCountFiltered1(node, delta) \
  	do { \
  		if (((PlanState *)(node))->instrument) \
  			((PlanState *)(node))->instrument->nfiltered1 += (delta); \
  	} while(0)
  #define InstrCountFiltered2(node, delta) \
  	do { \
  		if (((PlanState *)(node))->instrument) \
  			((PlanState *)(node))->instrument->nfiltered2 += (delta); \
  	} while(0)
  
  /*
   * EPQState is state for executing an EvalPlanQual recheck on a candidate
   * tuples e.g. in ModifyTable or LockRows.
   *
   * To execute EPQ a separate EState is created (stored in ->recheckestate),
   * which shares some resources, like the rangetable, with the main query's
   * EState (stored in ->parentestate). The (sub-)tree of the plan that needs to
   * be rechecked (in ->plan), is separately initialized (into
   * ->recheckplanstate), but shares plan nodes with the corresponding nodes in
   * the main query. The scan nodes in that separate executor tree are changed
   * to return only the current tuple of interest for the respective
   * table. Those tuples are either provided by the caller (using
   * EvalPlanQualSlot), and/or found using the rowmark mechanism (non-locking
   * rowmarks by the EPQ machinery itself, locking ones by the caller).
   *
   * While the plan to be checked may be changed using EvalPlanQualSetPlan() -
   * e.g. so all source plans for a ModifyTable node can be processed - all such
   * plans need to share the same EState.
   */
  typedef struct EPQState
  {
  	/* Initialized at EvalPlanQualInit() time: */
  
  	EState	   *parentestate;	/* main query's EState */
  	int			epqParam;		/* ID of Param to force scan node re-eval */
  
  	/*
  	 * Tuples to be substituted by scan nodes. They need to set up, before
  	 * calling EvalPlanQual()/EvalPlanQualNext(), into the slot returned by
  	 * EvalPlanQualSlot(scanrelid). The array is indexed by scanrelid - 1.
  	 */
  	List	   *tuple_table;	/* tuple table for relsubs_slot */
  	TupleTableSlot **relsubs_slot;
  
  	/*
  	 * Initialized by EvalPlanQualInit(), may be changed later with
  	 * EvalPlanQualSetPlan():
  	 */
  
  	Plan	   *plan;			/* plan tree to be executed */
  	List	   *arowMarks;		/* ExecAuxRowMarks (non-locking only) */
  
  
  	/*
  	 * The original output tuple to be rechecked.  Set by
  	 * EvalPlanQualSetSlot(), before EvalPlanQualNext() or EvalPlanQual() may
  	 * be called.
  	 */
  	TupleTableSlot *origslot;
  
  
  	/* Initialized or reset by EvalPlanQualBegin(): */
  
  	EState	   *recheckestate;	/* EState for EPQ execution, see above */
  
  	/*
  	 * Rowmarks that can be fetched on-demand using
  	 * EvalPlanQualFetchRowMark(), indexed by scanrelid - 1. Only non-locking
  	 * rowmarks.
  	 */
  	ExecAuxRowMark **relsubs_rowmark;
  
  	/*
  	 * True if a relation's EPQ tuple has been fetched for relation, indexed
  	 * by scanrelid - 1.
  	 */
  	bool	   *relsubs_done;
  
  	PlanState  *recheckplanstate;	/* EPQ specific exec nodes, for ->plan */
  } EPQState;
  
  
  /* ----------------
   *	 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;
  
  /* ----------------
   *	 ProjectSetState information
   *
   * Note: at least one of the "elems" will be a SetExprState; the rest are
   * regular ExprStates.
   * ----------------
   */
  typedef struct ProjectSetState
  {
  	PlanState	ps;				/* its first field is NodeTag */
  	Node	  **elems;			/* array of expression states */
  	ExprDoneCond *elemdone;		/* array of per-SRF is-done states */
  	int			nelems;			/* length of elemdone[] array */
  	bool		pending_srf_tuples; /* still evaluating srfs in tlist? */
  	MemoryContext argcontext;	/* context for SRF arguments */
  } ProjectSetState;
  
  /* ----------------
   *	 ModifyTableState information
   * ----------------
   */
  typedef struct ModifyTableState
  {
  	PlanState	ps;				/* its first field is NodeTag */
  	CmdType		operation;		/* INSERT, UPDATE, or DELETE */
  	bool		canSetTag;		/* do we set the command tag/es_processed? */
  	bool		mt_done;		/* are we done? */
  	PlanState **mt_plans;		/* subplans (one per target rel) */
  	int			mt_nplans;		/* number of plans in the array */
  	int			mt_whichplan;	/* which one is being executed (0..n-1) */
  	TupleTableSlot **mt_scans;	/* input tuple corresponding to underlying
  								 * plans */
  	ResultRelInfo *resultRelInfo;	/* per-subplan target relations */
  	ResultRelInfo *rootResultRelInfo;	/* root target relation (partitioned
  										 * table root) */
  	List	  **mt_arowmarks;	/* per-subplan ExecAuxRowMark lists */
  	EPQState	mt_epqstate;	/* for evaluating EvalPlanQual rechecks */
  	bool		fireBSTriggers; /* do we need to fire stmt triggers? */
  	List	   *mt_excludedtlist;	/* the excluded pseudo relation's tlist  */
  
  	/*
  	 * Slot for storing tuples in the root partitioned table's rowtype during
  	 * an UPDATE of a partitioned table.
  	 */
  	TupleTableSlot *mt_root_tuple_slot;
  
  	/* Tuple-routing support info */
  	struct PartitionTupleRouting *mt_partition_tuple_routing;
  
  	/* controls transition table population for specified operation */
  	struct TransitionCaptureState *mt_transition_capture;
  
  	/* controls transition table population for INSERT...ON CONFLICT UPDATE */
  	struct TransitionCaptureState *mt_oc_transition_capture;
  
  	/* Per plan map for tuple conversion from child to root */
  	TupleConversionMap **mt_per_subplan_tupconv_maps;
  } ModifyTableState;
  
  /* ----------------
   *	 AppendState information
   *
   *		nplans				how many plans are in the array
   *		whichplan			which plan is being executed (0 .. n-1), or a
   *							special negative value. See nodeAppend.c.
   *		prune_state			details required to allow partitions to be
   *							eliminated from the scan, or NULL if not possible.
   *		valid_subplans		for runtime pruning, valid appendplans indexes to
   *							scan.
   * ----------------
   */
  
  struct AppendState;
  typedef struct AppendState AppendState;
  struct ParallelAppendState;
  typedef struct ParallelAppendState ParallelAppendState;
  struct PartitionPruneState;
  
  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_first_partial_plan;	/* Index of 'appendplans' containing
  										 * the first partial plan */
  	ParallelAppendState *as_pstate; /* parallel coordination info */
  	Size		pstate_len;		/* size of parallel coordination info */
  	struct PartitionPruneState *as_prune_state;
  	Bitmapset  *as_valid_subplans;
  	bool		(*choose_next_subplan) (AppendState *);
  };
  
  /* ----------------
   *	 MergeAppendState information
   *
   *		nplans			how many plans are in the array
   *		nkeys			number of sort key columns
   *		sortkeys		sort keys in SortSupport representation
   *		slots			current output tuple of each subplan
   *		heap			heap of active tuples
   *		initialized		true if we have fetched first tuple from each subplan
   *		noopscan		true if partition pruning proved that none of the
   *						mergeplans can contain a record to satisfy this query.
   *		prune_state		details required to allow partitions to be
   *						eliminated from the scan, or NULL if not possible.
   *		valid_subplans	for runtime pruning, valid mergeplans indexes to
   *						scan.
   * ----------------
   */
  typedef struct MergeAppendState
  {
  	PlanState	ps;				/* its first field is NodeTag */
  	PlanState **mergeplans;		/* array of PlanStates for my inputs */
  	int			ms_nplans;
  	int			ms_nkeys;
  	SortSupport ms_sortkeys;	/* array of length ms_nkeys */
  	TupleTableSlot **ms_slots;	/* array of length ms_nplans */
  	struct binaryheap *ms_heap; /* binary heap of slot indices */
  	bool		ms_initialized; /* are subplans started? */
  	bool		ms_noopscan;
  	struct PartitionPruneState *ms_prune_state;
  	Bitmapset  *ms_valid_subplans;
  } MergeAppendState;
  
  /* ----------------
   *	 RecursiveUnionState information
   *
   *		RecursiveUnionState is used for performing a recursive union.
   *
   *		recursing			T when we're done scanning the non-recursive term
   *		intermediate_empty	T if intermediate_table is currently empty
   *		working_table		working table (to be scanned by recursive term)
   *		intermediate_table	current recursive output (next generation of WT)
   * ----------------
   */
  typedef struct RecursiveUnionState
  {
  	PlanState	ps;				/* its first field is NodeTag */
  	bool		recursing;
  	bool		intermediate_empty;
  	Tuplestorestate *working_table;
  	Tuplestorestate *intermediate_table;
  	/* Remaining fields are unused in UNION ALL case */
  	Oid		   *eqfuncoids;		/* per-grouping-field equality fns */
  	FmgrInfo   *hashfunctions;	/* per-grouping-field hash fns */
  	MemoryContext tempContext;	/* short-term context for comparisons */
  	TupleHashTable hashtable;	/* hash table for tuples already seen */
  	MemoryContext tableContext; /* memory context containing hash table */
  } RecursiveUnionState;
  
  /* ----------------
   *	 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;
  	struct TableScanDescData *ss_currentScanDesc;
  	TupleTableSlot *ss_ScanTupleSlot;
  } ScanState;
  
  /* ----------------
   *	 SeqScanState information
   * ----------------
   */
  typedef struct SeqScanState
  {
  	ScanState	ss;				/* its first field is NodeTag */
  	Size		pscan_len;		/* size of parallel heap scan descriptor */
  } SeqScanState;
  
  /* ----------------
   *	 SampleScanState information
   * ----------------
   */
  typedef struct SampleScanState
  {
  	ScanState	ss;
  	List	   *args;			/* expr states for TABLESAMPLE params */
  	ExprState  *repeatable;		/* expr state for REPEATABLE expr */
  	/* use struct pointer to avoid including tsmapi.h here */
  	struct TsmRoutine *tsmroutine;	/* descriptor for tablesample method */
  	void	   *tsm_state;		/* tablesample method can keep state here */
  	bool		use_bulkread;	/* use bulkread buffer access strategy? */
  	bool		use_pagemode;	/* use page-at-a-time visibility checking? */
  	bool		begun;			/* false means need to call BeginSampleScan */
  	uint32		seed;			/* random seed */
  	int64		donetuples;		/* number of tuples already returned */
  	bool		haveblock;		/* has a block for sampling been determined */
  	bool		done;			/* exhausted all tuples? */
  } SampleScanState;
  
  /*
   * These structs store information about index quals that don't have simple
   * constant right-hand sides.  See comments for ExecIndexBuildScanKeys()
   * for discussion.
   */
  typedef struct
  {
  	struct ScanKeyData *scan_key;	/* scankey to put value into */
  	ExprState  *key_expr;		/* expr to evaluate to get value */
  	bool		key_toastable;	/* is expr's result a toastable datatype? */
  } IndexRuntimeKeyInfo;
  
  typedef struct
  {
  	struct ScanKeyData *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
   *		indexorderbyorig   execution state for indexorderbyorig expressions
   *		ScanKeys		   Skey structures for index quals
   *		NumScanKeys		   number of ScanKeys
   *		OrderByKeys		   Skey structures for index ordering operators
   *		NumOrderByKeys	   number of OrderByKeys
   *		RuntimeKeys		   info about Skeys that must be evaluated at runtime
   *		NumRuntimeKeys	   number of RuntimeKeys
   *		RuntimeKeysReady   true if runtime Skeys have been computed
   *		RuntimeContext	   expr context for evaling runtime Skeys
   *		RelationDesc	   index relation descriptor
   *		ScanDesc		   index scan descriptor
   *
   *		ReorderQueue	   tuples that need reordering due to re-check
   *		ReachedEnd		   have we fetched all tuples from index already?
   *		OrderByValues	   values of ORDER BY exprs of last fetched tuple
   *		OrderByNulls	   null flags for OrderByValues
   *		SortSupport		   for reordering ORDER BY exprs
   *		OrderByTypByVals   is the datatype of order by expression pass-by-value?
   *		OrderByTypLens	   typlens of the datatypes of order by expressions
   *		PscanLen		   size of parallel index scan descriptor
   * ----------------
   */
  typedef struct IndexScanState
  {
  	ScanState	ss;				/* its first field is NodeTag */
  	ExprState  *indexqualorig;
  	List	   *indexorderbyorig;
  	struct ScanKeyData *iss_ScanKeys;
  	int			iss_NumScanKeys;
  	struct ScanKeyData *iss_OrderByKeys;
  	int			iss_NumOrderByKeys;
  	IndexRuntimeKeyInfo *iss_RuntimeKeys;
  	int			iss_NumRuntimeKeys;
  	bool		iss_RuntimeKeysReady;
  	ExprContext *iss_RuntimeContext;
  	Relation	iss_RelationDesc;
  	struct IndexScanDescData *iss_ScanDesc;
  
  	/* These are needed for re-checking ORDER BY expr ordering */
  	pairingheap *iss_ReorderQueue;
  	bool		iss_ReachedEnd;
  	Datum	   *iss_OrderByValues;
  	bool	   *iss_OrderByNulls;
  	SortSupport iss_SortSupport;
  	bool	   *iss_OrderByTypByVals;
  	int16	   *iss_OrderByTypLens;
  	Size		iss_PscanLen;
  } IndexScanState;
  
  /* ----------------
   *	 IndexOnlyScanState information
   *
   *		indexqual		   execution state for indexqual expressions
   *		ScanKeys		   Skey structures for index quals
   *		NumScanKeys		   number of ScanKeys
   *		OrderByKeys		   Skey structures for index ordering operators
   *		NumOrderByKeys	   number of OrderByKeys
   *		RuntimeKeys		   info about Skeys that must be evaluated at runtime
   *		NumRuntimeKeys	   number of RuntimeKeys
   *		RuntimeKeysReady   true if runtime Skeys have been computed
   *		RuntimeContext	   expr context for evaling runtime Skeys
   *		RelationDesc	   index relation descriptor
   *		ScanDesc		   index scan descriptor
   *		TableSlot		   slot for holding tuples fetched from the table
   *		VMBuffer		   buffer in use for visibility map testing, if any
   *		PscanLen		   size of parallel index-only scan descriptor
   * ----------------
   */
  typedef struct IndexOnlyScanState
  {
  	ScanState	ss;				/* its first field is NodeTag */
  	ExprState  *indexqual;
  	struct ScanKeyData *ioss_ScanKeys;
  	int			ioss_NumScanKeys;
  	struct ScanKeyData *ioss_OrderByKeys;
  	int			ioss_NumOrderByKeys;
  	IndexRuntimeKeyInfo *ioss_RuntimeKeys;
  	int			ioss_NumRuntimeKeys;
  	bool		ioss_RuntimeKeysReady;
  	ExprContext *ioss_RuntimeContext;
  	Relation	ioss_RelationDesc;
  	struct IndexScanDescData *ioss_ScanDesc;
  	TupleTableSlot *ioss_TableSlot;
  	Buffer		ioss_VMBuffer;
  	Size		ioss_PscanLen;
  } IndexOnlyScanState;
  
  /* ----------------
   *	 BitmapIndexScanState information
   *
   *		result			   bitmap to return output into, or NULL
   *		ScanKeys		   Skey structures for index quals
   *		NumScanKeys		   number of ScanKeys
   *		RuntimeKeys		   info about Skeys that must be evaluated at runtime
   *		NumRuntimeKeys	   number of RuntimeKeys
   *		ArrayKeys		   info about Skeys that come from ScalarArrayOpExprs
   *		NumArrayKeys	   number of ArrayKeys
   *		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;
  	struct ScanKeyData *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;
  	struct IndexScanDescData *biss_ScanDesc;
  } BitmapIndexScanState;
  
  /* ----------------
   *	 SharedBitmapState information
   *
   *		BM_INITIAL		TIDBitmap creation is not yet started, so first worker
   *						to see this state will set the state to BM_INPROGRESS
   *						and that process will be responsible for creating
   *						TIDBitmap.
   *		BM_INPROGRESS	TIDBitmap creation is in progress; workers need to
   *						sleep until it's finished.
   *		BM_FINISHED		TIDBitmap creation is done, so now all workers can
   *						proceed to iterate over TIDBitmap.
   * ----------------
   */
  typedef enum
  {
  	BM_INITIAL,
  	BM_INPROGRESS,
  	BM_FINISHED
  } SharedBitmapState;
  
  /* ----------------
   *	 ParallelBitmapHeapState information
   *		tbmiterator				iterator for scanning current pages
   *		prefetch_iterator		iterator for prefetching ahead of current page
   *		mutex					mutual exclusion for the prefetching variable
   *								and state
   *		prefetch_pages			# pages prefetch iterator is ahead of current
   *		prefetch_target			current target prefetch distance
   *		state					current state of the TIDBitmap
   *		cv						conditional wait variable
   *		phs_snapshot_data		snapshot data shared to workers
   * ----------------
   */
  typedef struct ParallelBitmapHeapState
  {
  	dsa_pointer tbmiterator;
  	dsa_pointer prefetch_iterator;
  	slock_t		mutex;
  	int			prefetch_pages;
  	int			prefetch_target;
  	SharedBitmapState state;
  	ConditionVariable cv;
  	char		phs_snapshot_data[FLEXIBLE_ARRAY_MEMBER];
  } ParallelBitmapHeapState;
  
  /* ----------------
   *	 BitmapHeapScanState information
   *
   *		bitmapqualorig	   execution state for bitmapqualorig expressions
   *		tbm				   bitmap obtained from child index scan(s)
   *		tbmiterator		   iterator for scanning current pages
   *		tbmres			   current-page data
   *		can_skip_fetch	   can we potentially skip tuple fetches in this scan?
   *		return_empty_tuples number of empty tuples to return
   *		vmbuffer		   buffer for visibility-map lookups
   *		pvmbuffer		   ditto, for prefetched pages
   *		exact_pages		   total number of exact pages retrieved
   *		lossy_pages		   total number of lossy pages retrieved
   *		prefetch_iterator  iterator for prefetching ahead of current page
   *		prefetch_pages	   # pages prefetch iterator is ahead of current
   *		prefetch_target    current target prefetch distance
   *		prefetch_maximum   maximum value for prefetch_target
   *		pscan_len		   size of the shared memory for parallel bitmap
   *		initialized		   is node is ready to iterate
   *		shared_tbmiterator	   shared iterator
   *		shared_prefetch_iterator shared iterator for prefetching
   *		pstate			   shared state for parallel bitmap scan
   * ----------------
   */
  typedef struct BitmapHeapScanState
  {
  	ScanState	ss;				/* its first field is NodeTag */
  	ExprState  *bitmapqualorig;
  	TIDBitmap  *tbm;
  	TBMIterator *tbmiterator;
  	TBMIterateResult *tbmres;
  	bool		can_skip_fetch;
  	int			return_empty_tuples;
  	Buffer		vmbuffer;
  	Buffer		pvmbuffer;
  	long		exact_pages;
  	long		lossy_pages;
  	TBMIterator *prefetch_iterator;
  	int			prefetch_pages;
  	int			prefetch_target;
  	int			prefetch_maximum;
  	Size		pscan_len;
  	bool		initialized;
  	TBMSharedIterator *shared_tbmiterator;
  	TBMSharedIterator *shared_prefetch_iterator;
  	ParallelBitmapHeapState *pstate;
  } BitmapHeapScanState;
  
  /* ----------------
   *	 TidScanState information
   *
   *		tidexprs	   list of TidExpr structs (see nodeTidscan.c)
   *		isCurrentOf    scan has a CurrentOfExpr qual
   *		NumTids		   number of tids in this scan
   *		TidPtr		   index of currently fetched tid
   *		TidList		   evaluated item pointers (array of size NumTids)
   *		htup		   currently-fetched tuple, if any
   * ----------------
   */
  typedef struct TidScanState
  {
  	ScanState	ss;				/* its first field is NodeTag */
  	List	   *tss_tidexprs;
  	bool		tss_isCurrentOf;
  	int			tss_NumTids;
  	int			tss_TidPtr;
  	ItemPointerData *tss_TidList;
  	HeapTupleData tss_htup;
  } TidScanState;
  
  /* ----------------
   *	 SubqueryScanState information
   *
   *		SubqueryScanState is used for scanning a sub-query in the range table.
   *		ScanTupleSlot references the current output tuple of the sub-query.
   * ----------------
   */
  typedef struct SubqueryScanState
  {
  	ScanState	ss;				/* its first field is NodeTag */
  	PlanState  *subplan;
  } SubqueryScanState;
  
  /* ----------------
   *	 FunctionScanState information
   *
   *		Function nodes are used to scan the results of a
   *		function appearing in FROM (typically a function returning set).
   *
   *		eflags				node's capability flags
   *		ordinality			is this scan WITH ORDINALITY?
   *		simple				true if we have 1 function and no ordinality
   *		ordinal				current ordinal column value
   *		nfuncs				number of functions being executed
   *		funcstates			per-function execution states (private in
   *							nodeFunctionscan.c)
   *		argcontext			memory context to evaluate function arguments in
   * ----------------
   */
  struct FunctionScanPerFuncState;
  
  typedef struct FunctionScanState
  {
  	ScanState	ss;				/* its first field is NodeTag */
  	int			eflags;
  	bool		ordinality;
  	bool		simple;
  	int64		ordinal;
  	int			nfuncs;
  	struct FunctionScanPerFuncState *funcstates;	/* array of length nfuncs */
  	MemoryContext argcontext;
  } 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)
   *
   *	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;
  } ValuesScanState;
  
  /* ----------------
   *		TableFuncScanState node
   *
   * Used in table-expression functions like XMLTABLE.
   * ----------------
   */
  typedef struct TableFuncScanState
  {
  	ScanState	ss;				/* its first field is NodeTag */
  	ExprState  *docexpr;		/* state for document expression */
  	ExprState  *rowexpr;		/* state for row-generating expression */
  	List	   *colexprs;		/* state for column-generating expression */
  	List	   *coldefexprs;	/* state for column default expressions */
  	List	   *ns_names;		/* same as TableFunc.ns_names */
  	List	   *ns_uris;		/* list of states of namespace URI exprs */
  	Bitmapset  *notnulls;		/* nullability flag for each output column */
  	void	   *opaque;			/* table builder private space */
  	const struct TableFuncRoutine *routine; /* table builder methods */
  	FmgrInfo   *in_functions;	/* input function for each column */
  	Oid		   *typioparams;	/* typioparam for each column */
  	int64		ordinal;		/* row number to be output next */
  	MemoryContext perTableCxt;	/* per-table context */
  	Tuplestorestate *tupstore;	/* output tuple store */
  } TableFuncScanState;
  
  /* ----------------
   *	 CteScanState information
   *
   *		CteScan nodes are used to scan a CommonTableExpr query.
   *
   * Multiple CteScan nodes can read out from the same CTE query.  We use
   * a tuplestore to hold rows that have been read from the CTE query but
   * not yet consumed by all readers.
   * ----------------
   */
  typedef struct CteScanState
  {
  	ScanState	ss;				/* its first field is NodeTag */
  	int			eflags;			/* capability flags to pass to tuplestore */
  	int			readptr;		/* index of my tuplestore read pointer */
  	PlanState  *cteplanstate;	/* PlanState for the CTE query itself */
  	/* Link to the "leader" CteScanState (possibly this same node) */
  	struct CteScanState *leader;
  	/* The remaining fields are only valid in the "leader" CteScanState */
  	Tuplestorestate *cte_table; /* rows already read from the CTE query */
  	bool		eof_cte;		/* reached end of CTE query? */
  } CteScanState;
  
  /* ----------------
   *	 NamedTuplestoreScanState information
   *
   *		NamedTuplestoreScan nodes are used to scan a Tuplestore created and
   *		named prior to execution of the query.  An example is a transition
   *		table for an AFTER trigger.
   *
   * Multiple NamedTuplestoreScan nodes can read out from the same Tuplestore.
   * ----------------
   */
  typedef struct NamedTuplestoreScanState
  {
  	ScanState	ss;				/* its first field is NodeTag */
  	int			readptr;		/* index of my tuplestore read pointer */
  	TupleDesc	tupdesc;		/* format of the tuples in the tuplestore */
  	Tuplestorestate *relation;	/* the rows */
  } NamedTuplestoreScanState;
  
  /* ----------------
   *	 WorkTableScanState information
   *
   *		WorkTableScan nodes are used to scan the work table created by
   *		a RecursiveUnion node.  We locate the RecursiveUnion node
   *		during executor startup.
   * ----------------
   */
  typedef struct WorkTableScanState
  {
  	ScanState	ss;				/* its first field is NodeTag */
  	RecursiveUnionState *rustate;
  } WorkTableScanState;
  
  /* ----------------
   *	 ForeignScanState information
   *
   *		ForeignScan nodes are used to scan foreign-data tables.
   * ----------------
   */
  typedef struct ForeignScanState
  {
  	ScanState	ss;				/* its first field is NodeTag */
  	ExprState  *fdw_recheck_quals;	/* original quals not in ss.ps.qual */
  	Size		pscan_len;		/* size of parallel coordination information */
  	/* use struct pointer to avoid including fdwapi.h here */
  	struct FdwRoutine *fdwroutine;
  	void	   *fdw_state;		/* foreign-data wrapper can keep state here */
  } ForeignScanState;
  
  /* ----------------
   *	 CustomScanState information
   *
   *		CustomScan nodes are used to execute custom code within executor.
   *
   * Core code must avoid assuming that the CustomScanState is only as large as
   * the structure declared here; providers are allowed to make it the first
   * element in a larger structure, and typically would need to do so.  The
   * struct is actually allocated by the CreateCustomScanState method associated
   * with the plan node.  Any additional fields can be initialized there, or in
   * the BeginCustomScan method.
   * ----------------
   */
  struct CustomExecMethods;
  
  typedef struct CustomScanState
  {
  	ScanState	ss;
  	uint32		flags;			/* mask of CUSTOMPATH_* flags, see
  								 * nodes/extensible.h */
  	List	   *custom_ps;		/* list of child PlanState nodes, if any */
  	Size		pscan_len;		/* size of parallel coordination information */
  	const struct CustomExecMethods *methods;
  } CustomScanState;
  
  /* ----------------------------------------------------------------
   *				 Join State Information
   * ----------------------------------------------------------------
   */
  
  /* ----------------
   *	 JoinState information
   *
   *		Superclass for state nodes of join plans.
   * ----------------
   */
  typedef struct JoinState
  {
  	PlanState	ps;
  	JoinType	jointype;
  	bool		single_match;	/* True if we should skip to next outer tuple
  								 * after finding one inner match */
  	ExprState  *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 ExecMergeJoin state machine
   *		SkipMarkRestore    true if we may skip Mark and Restore operations
   *		ExtraMarks		   true to issue extra Mark operations on inner scan
   *		ConstFalseJoin	   true if we have a constant-false joinqual
   *		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_SkipMarkRestore;
  	bool		mj_ExtraMarks;
  	bool		mj_ConstFalseJoin;
  	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
   *
   *		hashclauses				original form of the hashjoin condition
   *		hj_OuterHashKeys		the outer hash keys in the hashjoin condition
   *		hj_HashOperators		the join operators in the hashjoin condition
   *		hj_HashTable			hash table for the hashjoin
   *								(NULL if table not built yet)
   *		hj_CurHashValue			hash value for current outer tuple
   *		hj_CurBucketNo			regular bucket# for current outer tuple
   *		hj_CurSkewBucketNo		skew bucket# for current outer tuple
   *		hj_CurTuple				last inner tuple matched to current outer
   *								tuple, or NULL if starting search
   *								(hj_CurXXX variables are undefined if
   *								OuterTupleSlot is empty!)
   *		hj_OuterTupleSlot		tuple slot for outer tuples
   *		hj_HashTupleSlot		tuple slot for inner (hashed) tuples
   *		hj_NullOuterTupleSlot	prepared null tuple for right/full outer joins
   *		hj_NullInnerTupleSlot	prepared null tuple for left/full outer joins
   *		hj_FirstOuterTupleSlot	first tuple retrieved from outer plan
   *		hj_JoinState			current state of ExecHashJoin state machine
   *		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 */
  	ExprState  *hashclauses;
  	List	   *hj_OuterHashKeys;	/* list of ExprState nodes */
  	List	   *hj_HashOperators;	/* list of operator OIDs */
  	List	   *hj_Collations;
  	HashJoinTable hj_HashTable;
  	uint32		hj_CurHashValue;
  	int			hj_CurBucketNo;
  	int			hj_CurSkewBucketNo;
  	HashJoinTuple hj_CurTuple;
  	TupleTableSlot *hj_OuterTupleSlot;
  	TupleTableSlot *hj_HashTupleSlot;
  	TupleTableSlot *hj_NullOuterTupleSlot;
  	TupleTableSlot *hj_NullInnerTupleSlot;
  	TupleTableSlot *hj_FirstOuterTupleSlot;
  	int			hj_JoinState;
  	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 */
  	int			eflags;			/* capability flags to pass to tuplestore */
  	bool		eof_underlying; /* reached end of underlying plan? */
  	Tuplestorestate *tuplestorestate;
  } MaterialState;
  
  /* ----------------
   *	 Shared memory container for per-worker sort information
   * ----------------
   */
  typedef struct SharedSortInfo
  {
  	int			num_workers;
  	TuplesortInstrumentation sinstrument[FLEXIBLE_ARRAY_MEMBER];
  } SharedSortInfo;
  
  /* ----------------
   *	 SortState information
   * ----------------
   */
  typedef struct SortState
  {
  	ScanState	ss;				/* its first field is NodeTag */
  	bool		randomAccess;	/* need random access to sort output? */
  	bool		bounded;		/* is the result set bounded? */
  	int64		bound;			/* if bounded, how many tuples are needed */
  	bool		sort_Done;		/* sort completed yet? */
  	bool		bounded_Done;	/* value of bounded we did the sort with */
  	int64		bound_Done;		/* value of bound we did the sort with */
  	void	   *tuplesortstate; /* private state of tuplesort.c */
  	bool		am_worker;		/* are we a worker? */
  	SharedSortInfo *shared_info;	/* one entry per worker */
  } SortState;
  
  /* ---------------------
   *	GroupState information
   * ---------------------
   */
  typedef struct GroupState
  {
  	ScanState	ss;				/* its first field is NodeTag */
  	ExprState  *eqfunction;		/* equality function */
  	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 AggStatePerTransData *AggStatePerTrans;
  typedef struct AggStatePerGroupData *AggStatePerGroup;
  typedef struct AggStatePerPhaseData *AggStatePerPhase;
  typedef struct AggStatePerHashData *AggStatePerHash;
  
  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!) */
  	int			numtrans;		/* number of pertrans items */
  	AggStrategy aggstrategy;	/* strategy mode */
  	AggSplit	aggsplit;		/* agg-splitting mode, see nodes.h */
  	AggStatePerPhase phase;		/* pointer to current phase data */
  	int			numphases;		/* number of phases (including phase 0) */
  	int			current_phase;	/* current phase number */
  	AggStatePerAgg peragg;		/* per-Aggref information */
  	AggStatePerTrans pertrans;	/* per-Trans state information */
  	ExprContext *hashcontext;	/* econtexts for long-lived data (hashtable) */
  	ExprContext **aggcontexts;	/* econtexts for long-lived data (per GS) */
  	ExprContext *tmpcontext;	/* econtext for input expressions */
  #define FIELDNO_AGGSTATE_CURAGGCONTEXT 14
  	ExprContext *curaggcontext; /* currently active aggcontext */
  	AggStatePerAgg curperagg;	/* currently active aggregate, if any */
  #define FIELDNO_AGGSTATE_CURPERTRANS 16
  	AggStatePerTrans curpertrans;	/* currently active trans state, if any */
  	bool		input_done;		/* indicates end of input */
  	bool		agg_done;		/* indicates completion of Agg scan */
  	int			projected_set;	/* The last projected grouping set */
  #define FIELDNO_AGGSTATE_CURRENT_SET 20
  	int			current_set;	/* The current grouping set being evaluated */
  	Bitmapset  *grouped_cols;	/* grouped cols in current projection */
  	List	   *all_grouped_cols;	/* list of all grouped cols in DESC order */
  	/* These fields are for grouping set phase data */
  	int			maxsets;		/* The max number of sets in any phase */
  	AggStatePerPhase phases;	/* array of all phases */
  	Tuplesortstate *sort_in;	/* sorted input to phases > 1 */
  	Tuplesortstate *sort_out;	/* input is copied here for next phase */
  	TupleTableSlot *sort_slot;	/* slot for sort results */
  	/* these fields are used in AGG_PLAIN and AGG_SORTED modes: */
  	AggStatePerGroup *pergroups;	/* grouping set indexed array of per-group
  									 * pointers */
  	HeapTuple	grp_firstTuple; /* copy of first tuple of current group */
  	/* these fields are used in AGG_HASHED and AGG_MIXED modes: */
  	bool		table_filled;	/* hash table filled yet? */
  	int			num_hashes;
  	AggStatePerHash perhash;	/* array of per-hashtable data */
  	AggStatePerGroup *hash_pergroup;	/* grouping set indexed array of
  										 * per-group pointers */
  
  	/* support for evaluation of agg input expressions: */
  #define FIELDNO_AGGSTATE_ALL_PERGROUPS 34
  	AggStatePerGroup *all_pergroups;	/* array of first ->pergroups, than
  										 * ->hash_pergroup */
  	ProjectionInfo *combinedproj;	/* projection machinery */
  } AggState;
  
  /* ----------------
   *	WindowAggState information
   * ----------------
   */
  /* these structs are private in nodeWindowAgg.c: */
  typedef struct WindowStatePerFuncData *WindowStatePerFunc;
  typedef struct WindowStatePerAggData *WindowStatePerAgg;
  
  typedef struct WindowAggState
  {
  	ScanState	ss;				/* its first field is NodeTag */
  
  	/* these fields are filled in by ExecInitExpr: */
  	List	   *funcs;			/* all WindowFunc nodes in targetlist */
  	int			numfuncs;		/* total number of window functions */
  	int			numaggs;		/* number that are plain aggregates */
  
  	WindowStatePerFunc perfunc; /* per-window-function information */
  	WindowStatePerAgg peragg;	/* per-plain-aggregate information */
  	ExprState  *partEqfunction; /* equality funcs for partition columns */
  	ExprState  *ordEqfunction;	/* equality funcs for ordering columns */
  	Tuplestorestate *buffer;	/* stores rows of current partition */
  	int			current_ptr;	/* read pointer # for current row */
  	int			framehead_ptr;	/* read pointer # for frame head, if used */
  	int			frametail_ptr;	/* read pointer # for frame tail, if used */
  	int			grouptail_ptr;	/* read pointer # for group tail, if used */
  	int64		spooled_rows;	/* total # of rows in buffer */
  	int64		currentpos;		/* position of current row in partition */
  	int64		frameheadpos;	/* current frame head position */
  	int64		frametailpos;	/* current frame tail position (frame end+1) */
  	/* use struct pointer to avoid including windowapi.h here */
  	struct WindowObjectData *agg_winobj;	/* winobj for aggregate fetches */
  	int64		aggregatedbase; /* start row for current aggregates */
  	int64		aggregatedupto; /* rows before this one are aggregated */
  
  	int			frameOptions;	/* frame_clause options, see WindowDef */
  	ExprState  *startOffset;	/* expression for starting bound offset */
  	ExprState  *endOffset;		/* expression for ending bound offset */
  	Datum		startOffsetValue;	/* result of startOffset evaluation */
  	Datum		endOffsetValue; /* result of endOffset evaluation */
  
  	/* these fields are used with RANGE offset PRECEDING/FOLLOWING: */
  	FmgrInfo	startInRangeFunc;	/* in_range function for startOffset */
  	FmgrInfo	endInRangeFunc; /* in_range function for endOffset */
  	Oid			inRangeColl;	/* collation for in_range tests */
  	bool		inRangeAsc;		/* use ASC sort order for in_range tests? */
  	bool		inRangeNullsFirst;	/* nulls sort first for in_range tests? */
  
  	/* these fields are used in GROUPS mode: */
  	int64		currentgroup;	/* peer group # of current row in partition */
  	int64		frameheadgroup; /* peer group # of frame head row */
  	int64		frametailgroup; /* peer group # of frame tail row */
  	int64		groupheadpos;	/* current row's peer group head position */
  	int64		grouptailpos;	/* " " " " tail position (group end+1) */
  
  	MemoryContext partcontext;	/* context for partition-lifespan data */
  	MemoryContext aggcontext;	/* shared context for aggregate working data */
  	MemoryContext curaggcontext;	/* current aggregate's working data */
  	ExprContext *tmpcontext;	/* short-term evaluation context */
  
  	bool		all_first;		/* true if the scan is starting */
  	bool		all_done;		/* true if the scan is finished */
  	bool		partition_spooled;	/* true if all tuples in current partition
  									 * have been spooled into tuplestore */
  	bool		more_partitions;	/* true if there's more partitions after
  									 * this one */
  	bool		framehead_valid;	/* true if frameheadpos is known up to
  									 * date for current row */
  	bool		frametail_valid;	/* true if frametailpos is known up to
  									 * date for current row */
  	bool		grouptail_valid;	/* true if grouptailpos is known up to
  									 * date for current row */
  
  	TupleTableSlot *first_part_slot;	/* first tuple of current or next
  										 * partition */
  	TupleTableSlot *framehead_slot; /* first tuple of current frame */
  	TupleTableSlot *frametail_slot; /* first tuple after current frame */
  
  	/* temporary slots for tuples fetched back from tuplestore */
  	TupleTableSlot *agg_row_slot;
  	TupleTableSlot *temp_slot_1;
  	TupleTableSlot *temp_slot_2;
  } WindowAggState;
  
  /* ----------------
   *	 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 */
  	ExprState  *eqfunction;		/* tuple equality qual */
  } UniqueState;
  
  /* ----------------
   * GatherState information
   *
   *		Gather nodes launch 1 or more parallel workers, run a subplan
   *		in those workers, and collect the results.
   * ----------------
   */
  typedef struct GatherState
  {
  	PlanState	ps;				/* its first field is NodeTag */
  	bool		initialized;	/* workers launched? */
  	bool		need_to_scan_locally;	/* need to read from local plan? */
  	int64		tuples_needed;	/* tuple bound, see ExecSetTupleBound */
  	/* these fields are set up once: */
  	TupleTableSlot *funnel_slot;
  	struct ParallelExecutorInfo *pei;
  	/* all remaining fields are reinitialized during a rescan: */
  	int			nworkers_launched;	/* original number of workers */
  	int			nreaders;		/* number of still-active workers */
  	int			nextreader;		/* next one to try to read from */
  	struct TupleQueueReader **reader;	/* array with nreaders active entries */
  } GatherState;
  
  /* ----------------
   * GatherMergeState information
   *
   *		Gather merge nodes launch 1 or more parallel workers, run a
   *		subplan which produces sorted output in each worker, and then
   *		merge the results into a single sorted stream.
   * ----------------
   */
  struct GMReaderTupleBuffer;		/* private in nodeGatherMerge.c */
  
  typedef struct GatherMergeState
  {
  	PlanState	ps;				/* its first field is NodeTag */
  	bool		initialized;	/* workers launched? */
  	bool		gm_initialized; /* gather_merge_init() done? */
  	bool		need_to_scan_locally;	/* need to read from local plan? */
  	int64		tuples_needed;	/* tuple bound, see ExecSetTupleBound */
  	/* these fields are set up once: */
  	TupleDesc	tupDesc;		/* descriptor for subplan result tuples */
  	int			gm_nkeys;		/* number of sort columns */
  	SortSupport gm_sortkeys;	/* array of length gm_nkeys */
  	struct ParallelExecutorInfo *pei;
  	/* all remaining fields are reinitialized during a rescan */
  	/* (but the arrays are not reallocated, just cleared) */
  	int			nworkers_launched;	/* original number of workers */
  	int			nreaders;		/* number of active workers */
  	TupleTableSlot **gm_slots;	/* array with nreaders+1 entries */
  	struct TupleQueueReader **reader;	/* array with nreaders active entries */
  	struct GMReaderTupleBuffer *gm_tuple_buffers;	/* nreaders tuple buffers */
  	struct binaryheap *gm_heap; /* binary heap of slot indices */
  } GatherMergeState;
  
  /* ----------------
   *	 Values displayed by EXPLAIN ANALYZE
   * ----------------
   */
  typedef struct HashInstrumentation
  {
  	int			nbuckets;		/* number of buckets at end of execution */
  	int			nbuckets_original;	/* planned number of buckets */
  	int			nbatch;			/* number of batches at end of execution */
  	int			nbatch_original;	/* planned number of batches */
  	size_t		space_peak;		/* speak memory usage in bytes */
  } HashInstrumentation;
  
  /* ----------------
   *	 Shared memory container for per-worker hash information
   * ----------------
   */
  typedef struct SharedHashInfo
  {
  	int			num_workers;
  	HashInstrumentation hinstrument[FLEXIBLE_ARRAY_MEMBER];
  } SharedHashInfo;
  
  /* ----------------
   *	 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 */
  
  	SharedHashInfo *shared_info;	/* one entry per worker */
  	HashInstrumentation *hinstrument;	/* this worker's entry */
  
  	/* Parallel hash state. */
  	struct ParallelHashJoinState *parallel_state;
  } HashState;
  
  /* ----------------
   *	 SetOpState information
   *
   *		Even in "sorted" mode, SetOp nodes are more complex than a simple
   *		Unique, since we have to count how many duplicates to return.  But
   *		we also support hashing, so this is really more like a cut-down
   *		form of Agg.
   * ----------------
   */
  /* this struct is private in nodeSetOp.c: */
  typedef struct SetOpStatePerGroupData *SetOpStatePerGroup;
  
  typedef struct SetOpState
  {
  	PlanState	ps;				/* its first field is NodeTag */
  	ExprState  *eqfunction;		/* equality comparator */
  	Oid		   *eqfuncoids;		/* per-grouping-field equality fns */
  	FmgrInfo   *hashfunctions;	/* per-grouping-field hash fns */
  	bool		setop_done;		/* indicates completion of output scan */
  	long		numOutput;		/* number of dups left to output */
  	/* these fields are used in SETOP_SORTED mode: */
  	SetOpStatePerGroup pergroup;	/* per-group working state */
  	HeapTuple	grp_firstTuple; /* copy of first tuple of current group */
  	/* these fields are used in SETOP_HASHED mode: */
  	TupleHashTable hashtable;	/* hash table with one entry per group */
  	MemoryContext tableContext; /* memory context containing hash table */
  	bool		table_filled;	/* hash table filled yet? */
  	TupleHashIterator hashiter; /* for iterating through hash table */
  } SetOpState;
  
  /* ----------------
   *	 LockRowsState information
   *
   *		LockRows nodes are used to enforce FOR [KEY] UPDATE/SHARE locking.
   * ----------------
   */
  typedef struct LockRowsState
  {
  	PlanState	ps;				/* its first field is NodeTag */
  	List	   *lr_arowMarks;	/* List of ExecAuxRowMarks */
  	EPQState	lr_epqstate;	/* for evaluating EvalPlanQual rechecks */
  } LockRowsState;
  
  /* ----------------
   *	 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_RESCAN,				/* rescan after recomputing parameters */
  	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 */
  