execnodes.h

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/*-------------------------------------------------------------------------
 *
 * execnodes.h
 *    definitions for executor state nodes
 *
 *
 * Portions Copyright (c) 1996-2013, 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 [KEY] UPDATE/SHARE clauses
 *
 * When doing UPDATE, DELETE, or SELECT FOR [KEY] 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 [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_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;

/* ----------------
 *      WholeRowVarExprState node
 * ----------------
 */
typedef struct WholeRowVarExprState
{
    ExprState   xprstate;
    struct PlanState *parent;   /* parent PlanState, or NULL if none */
    JunkFilter *wrv_junkFilter; /* JunkFilter to remove resjunk cols */
} WholeRowVarExprState;

/* ----------------
 *      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;

/* ----------------
 *  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 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
 * tuple in ModifyTable or LockRows.  The estate and planstate fields are
 * NULL if inactive.
 */
typedef struct EPQState
{
    EState     *estate;         /* subsidiary EState */
    PlanState  *planstate;      /* plan state tree ready to be executed */
    TupleTableSlot *origslot;   /* original output tuple to be rechecked */
    Plan       *plan;           /* plan tree to be executed */
    List       *arowMarks;      /* ExecAuxRowMarks (non-locking only) */
    int         epqParam;       /* ID of Param to force scan node re-eval */
} 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;

/* ----------------
 *   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) */
    ResultRelInfo *resultRelInfo;       /* per-subplan target relations */
    List      **mt_arowmarks;   /* per-subplan ExecAuxRowMark lists */
    EPQState    mt_epqstate;    /* for evaluating EvalPlanQual rechecks */
    bool        fireBSTriggers; /* do we need to fire stmt triggers? */
} ModifyTableState;

/* ----------------
 *   AppendState information
 *
 *      nplans          how many plans are in the array
 *      whichplan       which plan is being executed (0 .. n-1)
 * ----------------
 */
typedef struct AppendState
{
    PlanState   ps;             /* its first field is NodeTag */
    PlanState **appendplans;    /* array of PlanStates for my inputs */
    int         as_nplans;
    int         as_whichplan;
} 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
 * ----------------
 */
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? */
} 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 */
    FmgrInfo   *eqfunctions;    /* 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;
    HeapScanDesc ss_currentScanDesc;
    TupleTableSlot *ss_ScanTupleSlot;
} ScanState;

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

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

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

/* ----------------
 *   IndexScanState information
 *
 *      indexqualorig      execution state for indexqualorig expressions
 *      ScanKeys           Skey structures 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
 * ----------------
 */
typedef struct IndexScanState
{
    ScanState   ss;             /* its first field is NodeTag */
    List       *indexqualorig;
    ScanKey     iss_ScanKeys;
    int         iss_NumScanKeys;
    ScanKey     iss_OrderByKeys;
    int         iss_NumOrderByKeys;
    IndexRuntimeKeyInfo *iss_RuntimeKeys;
    int         iss_NumRuntimeKeys;
    bool        iss_RuntimeKeysReady;
    ExprContext *iss_RuntimeContext;
    Relation    iss_RelationDesc;
    IndexScanDesc iss_ScanDesc;
} 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
 *      VMBuffer           buffer in use for visibility map testing, if any
 *      HeapFetches        number of tuples we were forced to fetch from heap
 * ----------------
 */
typedef struct IndexOnlyScanState
{
    ScanState   ss;             /* its first field is NodeTag */
    List       *indexqual;
    ScanKey     ioss_ScanKeys;
    int         ioss_NumScanKeys;
    ScanKey     ioss_OrderByKeys;
    int         ioss_NumOrderByKeys;
    IndexRuntimeKeyInfo *ioss_RuntimeKeys;
    int         ioss_NumRuntimeKeys;
    bool        ioss_RuntimeKeysReady;
    ExprContext *ioss_RuntimeContext;
    Relation    ioss_RelationDesc;
    IndexScanDesc ioss_ScanDesc;
    Buffer      ioss_VMBuffer;
    long        ioss_HeapFetches;
} 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;
    ScanKey     biss_ScanKeys;
    int         biss_NumScanKeys;
    IndexRuntimeKeyInfo *biss_RuntimeKeys;
    int         biss_NumRuntimeKeys;
    IndexArrayKeyInfo *biss_ArrayKeys;
    int         biss_NumArrayKeys;
    bool        biss_RuntimeKeysReady;
    ExprContext *biss_RuntimeContext;
    Relation    biss_RelationDesc;
    IndexScanDesc biss_ScanDesc;
} BitmapIndexScanState;

/* ----------------
 *   BitmapHeapScanState information
 *
 *      bitmapqualorig     execution state for bitmapqualorig expressions
 *      tbm                bitmap obtained from child index scan(s)
 *      tbmiterator        iterator for scanning current pages
 *      tbmres             current-page data
 *      prefetch_iterator  iterator for prefetching ahead of current page
 *      prefetch_pages     # pages prefetch iterator is ahead of current
 *      prefetch_target    target prefetch distance
 * ----------------
 */
typedef struct BitmapHeapScanState
{
    ScanState   ss;             /* its first field is NodeTag */
    List       *bitmapqualorig;
    TIDBitmap  *tbm;
    TBMIterator *tbmiterator;
    TBMIterateResult *tbmres;
    TBMIterator *prefetch_iterator;
    int         prefetch_pages;
    int         prefetch_target;
} BitmapHeapScanState;

/* ----------------
 *   TidScanState information
 *
 *      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)
 * ----------------
 */
typedef struct TidScanState
{
    ScanState   ss;             /* its first field is NodeTag */
    List       *tss_tidquals;   /* list of ExprState nodes */
    bool        tss_isCurrentOf;
    int         tss_NumTids;
    int         tss_TidPtr;
    int         tss_MarkTidPtr;
    ItemPointerData *tss_TidList;
    HeapTupleData tss_htup;
} TidScanState;

/* ----------------
 *   SubqueryScanState information
 *
 *      SubqueryScanState is used for scanning a sub-query in the range table.
 *      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
 *      tupdesc             expected return tuple description
 *      tuplestorestate     private state of tuplestore.c
 *      funcexpr            state for function expression being evaluated
 * ----------------
 */
typedef struct FunctionScanState
{
    ScanState   ss;             /* its first field is NodeTag */
    int         eflags;
    TupleDesc   tupdesc;
    Tuplestorestate *tuplestorestate;
    ExprState  *funcexpr;
} FunctionScanState;

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

/* ----------------
 *   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;

/* ----------------
 *   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 */
    /* use struct pointer to avoid including fdwapi.h here */
    struct FdwRoutine *fdwroutine;
    void       *fdw_state;      /* foreign-data wrapper can keep state here */
} ForeignScanState;

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

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

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

/* ----------------
 *   MergeJoinState information
 *
 *      NumClauses         number of mergejoinable join clauses
 *      Clauses            info for each mergejoinable clause
 *      JoinState          current state of ExecMergeJoin state machine
 *      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_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_InnerHashKeys        the inner 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 */
    List       *hashclauses;    /* list of ExprState nodes */
    List       *hj_OuterHashKeys;       /* list of ExprState nodes */
    List       *hj_InnerHashKeys;       /* list of ExprState nodes */
    List       *hj_HashOperators;       /* list of operator OIDs */
    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;

/* ----------------
 *   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 */
} SortState;

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

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

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

/* ----------------
 *  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 */
    FmgrInfo   *partEqfunctions;    /* equality funcs for partition columns */
    FmgrInfo   *ordEqfunctions; /* equality funcs for ordering columns */
    Tuplestorestate *buffer;    /* stores rows of current partition */
    int         current_ptr;    /* read pointer # for current */
    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 */
    /* 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 */

    MemoryContext partcontext;  /* context for partition-lifespan data */
    MemoryContext aggcontext;   /* context for each aggregate 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 */

    TupleTableSlot *first_part_slot;    /* first tuple of current or next
                                         * partition */

    /* 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 */
    FmgrInfo   *eqfunctions;    /* per-field lookup data for equality fns */
    MemoryContext tempContext;  /* short-term context for comparisons */
} UniqueState;

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

/* ----------------
 *   SetOpState information
 *
 *      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 */
    FmgrInfo   *eqfunctions;    /* 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 */
    MemoryContext tempContext;  /* short-term context for comparisons */
    /* 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 */