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File Content: `plannodes.h`

/*-------------------------------------------------------------------------
 *
 * plannodes.h
 *	  definitions for query plan nodes
 *
 *
 * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/nodes/plannodes.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef PLANNODES_H
#define PLANNODES_H

#include "access/sdir.h"
#include "nodes/bitmapset.h"
#include "nodes/primnodes.h"


/* ----------------------------------------------------------------
 *						node definitions
 * ----------------------------------------------------------------
 */

/* ----------------
 *		PlannedStmt node
 *
 * The output of the planner is a Plan tree headed by a PlannedStmt node.
 * PlannedStmt holds the "one time" information needed by the executor.
 * ----------------
 */
typedef struct PlannedStmt
{
	NodeTag		type;

	CmdType		commandType;	/* select|insert|update|delete */

	uint32		queryId;		/* query identifier (copied from Query) */

	bool		hasReturning;	/* is it insert|update|delete RETURNING? */

	bool		hasModifyingCTE;	/* has insert|update|delete in WITH? */

	bool		canSetTag;		/* do I set the command result tag? */

	bool		transientPlan;	/* redo plan when TransactionXmin changes? */

	struct Plan *planTree;		/* tree of Plan nodes */

	List	   *rtable;			/* list of RangeTblEntry nodes */

	/* rtable indexes of target relations for INSERT/UPDATE/DELETE */
	List	   *resultRelations;	/* integer list of RT indexes, or NIL */

	Node	   *utilityStmt;	/* non-null if this is DECLARE CURSOR */

	List	   *subplans;		/* Plan trees for SubPlan expressions */

	Bitmapset  *rewindPlanIDs;	/* indices of subplans that require REWIND */

	List	   *rowMarks;		/* a list of PlanRowMark's */

	List	   *relationOids;	/* OIDs of relations the plan depends on */

	List	   *invalItems;		/* other dependencies, as PlanInvalItems */

	int			nParamExec;		/* number of PARAM_EXEC Params used */
} PlannedStmt;

/* macro for fetching the Plan associated with a SubPlan node */
#define exec_subplan_get_plan(plannedstmt, subplan) \
	((Plan *) list_nth((plannedstmt)->subplans, (subplan)->plan_id - 1))


/* ----------------
 *		Plan node
 *
 * All plan nodes "derive" from the Plan structure by having the
 * Plan structure as the first field.  This ensures that everything works
 * when nodes are cast to Plan's.  (node pointers are frequently cast to Plan*
 * when passed around generically in the executor)
 *
 * We never actually instantiate any Plan nodes; this is just the common
 * abstract superclass for all Plan-type nodes.
 * ----------------
 */
typedef struct Plan
{
	NodeTag		type;

	/*
	 * estimated execution costs for plan (see costsize.c for more info)
	 */
	Cost		startup_cost;	/* cost expended before fetching any tuples */
	Cost		total_cost;		/* total cost (assuming all tuples fetched) */

	/*
	 * planner's estimate of result size of this plan step
	 */
	double		plan_rows;		/* number of rows plan is expected to emit */
	int			plan_width;		/* average row width in bytes */

	/*
	 * Common structural data for all Plan types.
	 */
	List	   *targetlist;		/* target list to be computed at this node */
	List	   *qual;			/* implicitly-ANDed qual conditions */
	struct Plan *lefttree;		/* input plan tree(s) */
	struct Plan *righttree;
	List	   *initPlan;		/* Init Plan nodes (un-correlated expr
								 * subselects) */

	/*
	 * Information for management of parameter-change-driven rescanning
	 *
	 * extParam includes the paramIDs of all external PARAM_EXEC params
	 * affecting this plan node or its children.  setParam params from the
	 * node's initPlans are not included, but their extParams are.
	 *
	 * allParam includes all the extParam paramIDs, plus the IDs of local
	 * params that affect the node (i.e., the setParams of its initplans).
	 * These are _all_ the PARAM_EXEC params that affect this node.
	 */
	Bitmapset  *extParam;
	Bitmapset  *allParam;
} Plan;

/* ----------------
 *	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 innerPlan(node)			(((Plan *)(node))->righttree)
#define outerPlan(node)			(((Plan *)(node))->lefttree)


/* ----------------
 *	 Result node -
 *		If no outer plan, evaluate a variable-free targetlist.
 *		If outer plan, return tuples from outer plan (after a level of
 *		projection as shown by targetlist).
 *
 * If resconstantqual isn't NULL, it represents a one-time qualification
 * test (i.e., one that doesn't depend on any variables from the outer plan,
 * so needs to be evaluated only once).
 * ----------------
 */
typedef struct Result
{
	Plan		plan;
	Node	   *resconstantqual;
} Result;

/* ----------------
 *	 ModifyTable node -
 *		Apply rows produced by subplan(s) to result table(s),
 *		by inserting, updating, or deleting.
 *
 * Note that rowMarks and epqParam are presumed to be valid for all the
 * subplan(s); they can't contain any info that varies across subplans.
 * ----------------
 */
typedef struct ModifyTable
{
	Plan		plan;
	CmdType		operation;		/* INSERT, UPDATE, or DELETE */
	bool		canSetTag;		/* do we set the command tag/es_processed? */
	List	   *resultRelations;	/* integer list of RT indexes */
	int			resultRelIndex; /* index of first resultRel in plan's list */
	List	   *plans;			/* plan(s) producing source data */
	List	   *returningLists; /* per-target-table RETURNING tlists */
	List	   *rowMarks;		/* PlanRowMarks (non-locking only) */
	int			epqParam;		/* ID of Param for EvalPlanQual re-eval */
} ModifyTable;

/* ----------------
 *	 Append node -
 *		Generate the concatenation of the results of sub-plans.
 * ----------------
 */
typedef struct Append
{
	Plan		plan;
	List	   *appendplans;
} Append;

/* ----------------
 *	 MergeAppend node -
 *		Merge the results of pre-sorted sub-plans to preserve the ordering.
 * ----------------
 */
typedef struct MergeAppend
{
	Plan		plan;
	List	   *mergeplans;
	/* remaining fields are just like the sort-key info in struct Sort */
	int			numCols;		/* number of sort-key columns */
	AttrNumber *sortColIdx;		/* their indexes in the target list */
	Oid		   *sortOperators;	/* OIDs of operators to sort them by */
	Oid		   *collations;		/* OIDs of collations */
	bool	   *nullsFirst;		/* NULLS FIRST/LAST directions */
} MergeAppend;

/* ----------------
 *	RecursiveUnion node -
 *		Generate a recursive union of two subplans.
 *
 * The "outer" subplan is always the non-recursive term, and the "inner"
 * subplan is the recursive term.
 * ----------------
 */
typedef struct RecursiveUnion
{
	Plan		plan;
	int			wtParam;		/* ID of Param representing work table */
	/* Remaining fields are zero/null in UNION ALL case */
	int			numCols;		/* number of columns to check for
								 * duplicate-ness */
	AttrNumber *dupColIdx;		/* their indexes in the target list */
	Oid		   *dupOperators;	/* equality operators to compare with */
	long		numGroups;		/* estimated number of groups in input */
} RecursiveUnion;

/* ----------------
 *	 BitmapAnd node -
 *		Generate the intersection of the results of sub-plans.
 *
 * The subplans must be of types that yield tuple bitmaps.  The targetlist
 * and qual fields of the plan are unused and are always NIL.
 * ----------------
 */
typedef struct BitmapAnd
{
	Plan		plan;
	List	   *bitmapplans;
} BitmapAnd;

/* ----------------
 *	 BitmapOr node -
 *		Generate the union of the results of sub-plans.
 *
 * The subplans must be of types that yield tuple bitmaps.  The targetlist
 * and qual fields of the plan are unused and are always NIL.
 * ----------------
 */
typedef struct BitmapOr
{
	Plan		plan;
	List	   *bitmapplans;
} BitmapOr;

/*
 * ==========
 * Scan nodes
 * ==========
 */
typedef struct Scan
{
	Plan		plan;
	Index		scanrelid;		/* relid is index into the range table */
} Scan;

/* ----------------
 *		sequential scan node
 * ----------------
 */
typedef Scan SeqScan;

/* ----------------
 *		index scan node
 *
 * indexqualorig is an implicitly-ANDed list of index qual expressions, each
 * in the same form it appeared in the query WHERE condition.  Each should
 * be of the form (indexkey OP comparisonval) or (comparisonval OP indexkey).
 * The indexkey is a Var or expression referencing column(s) of the index's
 * base table.  The comparisonval might be any expression, but it won't use
 * any columns of the base table.  The expressions are ordered by index
 * column position (but items referencing the same index column can appear
 * in any order).  indexqualorig is used at runtime only if we have to recheck
 * a lossy indexqual.
 *
 * indexqual has the same form, but the expressions have been commuted if
 * necessary to put the indexkeys on the left, and the indexkeys are replaced
 * by Var nodes identifying the index columns (their varno is INDEX_VAR and
 * their varattno is the index column number).
 *
 * indexorderbyorig is similarly the original form of any ORDER BY expressions
 * that are being implemented by the index, while indexorderby is modified to
 * have index column Vars on the left-hand side.  Here, multiple expressions
 * must appear in exactly the ORDER BY order, and this is not necessarily the
 * index column order.  Only the expressions are provided, not the auxiliary
 * sort-order information from the ORDER BY SortGroupClauses; it's assumed
 * that the sort ordering is fully determinable from the top-level operators.
 * indexorderbyorig is unused at run time, but is needed for EXPLAIN.
 * (Note these fields are used for amcanorderbyop cases, not amcanorder cases.)
 *
 * indexorderdir specifies the scan ordering, for indexscans on amcanorder
 * indexes (for other indexes it should be "don't care").
 * ----------------
 */
typedef struct IndexScan
{
	Scan		scan;
	Oid			indexid;		/* OID of index to scan */
	List	   *indexqual;		/* list of index quals (usually OpExprs) */
	List	   *indexqualorig;	/* the same in original form */
	List	   *indexorderby;	/* list of index ORDER BY exprs */
	List	   *indexorderbyorig;		/* the same in original form */
	ScanDirection indexorderdir;	/* forward or backward or don't care */
} IndexScan;

/* ----------------
 *		index-only scan node
 *
 * IndexOnlyScan is very similar to IndexScan, but it specifies an
 * index-only scan, in which the data comes from the index not the heap.
 * Because of this, *all* Vars in the plan node's targetlist, qual, and
 * index expressions reference index columns and have varno = INDEX_VAR.
 * Hence we do not need separate indexqualorig and indexorderbyorig lists,
 * since their contents would be equivalent to indexqual and indexorderby.
 *
 * To help EXPLAIN interpret the index Vars for display, we provide
 * indextlist, which represents the contents of the index as a targetlist
 * with one TLE per index column.  Vars appearing in this list reference
 * the base table, and this is the only field in the plan node that may
 * contain such Vars.
 * ----------------
 */
typedef struct IndexOnlyScan
{
	Scan		scan;
	Oid			indexid;		/* OID of index to scan */
	List	   *indexqual;		/* list of index quals (usually OpExprs) */
	List	   *indexorderby;	/* list of index ORDER BY exprs */
	List	   *indextlist;		/* TargetEntry list describing index's cols */
	ScanDirection indexorderdir;	/* forward or backward or don't care */
} IndexOnlyScan;

/* ----------------
 *		bitmap index scan node
 *
 * BitmapIndexScan delivers a bitmap of potential tuple locations;
 * it does not access the heap itself.  The bitmap is used by an
 * ancestor BitmapHeapScan node, possibly after passing through
 * intermediate BitmapAnd and/or BitmapOr nodes to combine it with
 * the results of other BitmapIndexScans.
 *
 * The fields have the same meanings as for IndexScan, except we don't
 * store a direction flag because direction is uninteresting.
 *
 * In a BitmapIndexScan plan node, the targetlist and qual fields are
 * not used and are always NIL.  The indexqualorig field is unused at
 * run time too, but is saved for the benefit of EXPLAIN.
 * ----------------
 */
typedef struct BitmapIndexScan
{
	Scan		scan;
	Oid			indexid;		/* OID of index to scan */
	List	   *indexqual;		/* list of index quals (OpExprs) */
	List	   *indexqualorig;	/* the same in original form */
} BitmapIndexScan;

/* ----------------
 *		bitmap sequential scan node
 *
 * This needs a copy of the qual conditions being used by the input index
 * scans because there are various cases where we need to recheck the quals;
 * for example, when the bitmap is lossy about the specific rows on a page
 * that meet the index condition.
 * ----------------
 */
typedef struct BitmapHeapScan
{
	Scan		scan;
	List	   *bitmapqualorig; /* index quals, in standard expr form */
} BitmapHeapScan;

/* ----------------
 *		tid scan node
 *
 * tidquals is an implicitly OR'ed list of qual expressions of the form
 * "CTID = pseudoconstant" or "CTID = ANY(pseudoconstant_array)".
 * ----------------
 */
typedef struct TidScan
{
	Scan		scan;
	List	   *tidquals;		/* qual(s) involving CTID = something */
} TidScan;

/* ----------------
 *		subquery scan node
 *
 * SubqueryScan is for scanning the output of a sub-query in the range table.
 * We often need an extra plan node above the sub-query's plan to perform
 * expression evaluations (which we can't push into the sub-query without
 * risking changing its semantics).  Although we are not scanning a physical
 * relation, we make this a descendant of Scan anyway for code-sharing
 * purposes.
 *
 * Note: we store the sub-plan in the type-specific subplan field, not in
 * the generic lefttree field as you might expect.  This is because we do
 * not want plan-tree-traversal routines to recurse into the subplan without
 * knowing that they are changing Query contexts.
 * ----------------
 */
typedef struct SubqueryScan
{
	Scan		scan;
	Plan	   *subplan;
} SubqueryScan;

/* ----------------
 *		FunctionScan node
 * ----------------
 */
typedef struct FunctionScan
{
	Scan		scan;
	Node	   *funcexpr;		/* expression tree for func call */
	List	   *funccolnames;	/* output column names (string Value nodes) */
	List	   *funccoltypes;	/* OID list of column type OIDs */
	List	   *funccoltypmods; /* integer list of column typmods */
	List	   *funccolcollations;		/* OID list of column collation OIDs */
} FunctionScan;

/* ----------------
 *		ValuesScan node
 * ----------------
 */
typedef struct ValuesScan
{
	Scan		scan;
	List	   *values_lists;	/* list of expression lists */
} ValuesScan;

/* ----------------
 *		CteScan node
 * ----------------
 */
typedef struct CteScan
{
	Scan		scan;
	int			ctePlanId;		/* ID of init SubPlan for CTE */
	int			cteParam;		/* ID of Param representing CTE output */
} CteScan;

/* ----------------
 *		WorkTableScan node
 * ----------------
 */
typedef struct WorkTableScan
{
	Scan		scan;
	int			wtParam;		/* ID of Param representing work table */
} WorkTableScan;

/* ----------------
 *		ForeignScan node
 *
 * fdw_exprs and fdw_private are both under the control of the foreign-data
 * wrapper, but fdw_exprs is presumed to contain expression trees and will
 * be post-processed accordingly by the planner; fdw_private won't be.
 * Note that everything in both lists must be copiable by copyObject().
 * One way to store an arbitrary blob of bytes is to represent it as a bytea
 * Const.  Usually, though, you'll be better off choosing a representation
 * that can be dumped usefully by nodeToString().
 * ----------------
 */
typedef struct ForeignScan
{
	Scan		scan;
	List	   *fdw_exprs;		/* expressions that FDW may evaluate */
	List	   *fdw_private;	/* private data for FDW */
	bool		fsSystemCol;	/* true if any "system column" is needed */
} ForeignScan;


/*
 * ==========
 * Join nodes
 * ==========
 */

/* ----------------
 *		Join node
 *
 * jointype:	rule for joining tuples from left and right subtrees
 * joinqual:	qual conditions that came from JOIN/ON or JOIN/USING
 *				(plan.qual contains conditions that came from WHERE)
 *
 * When jointype is INNER, joinqual and plan.qual are semantically
 * interchangeable.  For OUTER jointypes, the two are *not* interchangeable;
 * only joinqual is used to determine whether a match has been found for
 * the purpose of deciding whether to generate null-extended tuples.
 * (But plan.qual is still applied before actually returning a tuple.)
 * For an outer join, only joinquals are allowed to be used as the merge
 * or hash condition of a merge or hash join.
 * ----------------
 */
typedef struct Join
{
	Plan		plan;
	JoinType	jointype;
	List	   *joinqual;		/* JOIN quals (in addition to plan.qual) */
} Join;

/* ----------------
 *		nest loop join node
 *
 * The nestParams list identifies any executor Params that must be passed
 * into execution of the inner subplan carrying values from the current row
 * of the outer subplan.  Currently we restrict these values to be simple
 * Vars, but perhaps someday that'd be worth relaxing.  (Note: during plan
 * creation, the paramval can actually be a PlaceHolderVar expression; but it
 * must be a Var with varno OUTER_VAR by the time it gets to the executor.)
 * ----------------
 */
typedef struct NestLoop
{
	Join		join;
	List	   *nestParams;		/* list of NestLoopParam nodes */
} NestLoop;

typedef struct NestLoopParam
{
	NodeTag		type;
	int			paramno;		/* number of the PARAM_EXEC Param to set */
	Var		   *paramval;		/* outer-relation Var to assign to Param */
} NestLoopParam;

/* ----------------
 *		merge join node
 *
 * The expected ordering of each mergeable column is described by a btree
 * opfamily OID, a collation OID, a direction (BTLessStrategyNumber or
 * BTGreaterStrategyNumber) and a nulls-first flag.  Note that the two sides
 * of each mergeclause may be of different datatypes, but they are ordered the
 * same way according to the common opfamily and collation.  The operator in
 * each mergeclause must be an equality operator of the indicated opfamily.
 * ----------------
 */
typedef struct MergeJoin
{
	Join		join;
	List	   *mergeclauses;	/* mergeclauses as expression trees */
	/* these are arrays, but have the same length as the mergeclauses list: */
	Oid		   *mergeFamilies;	/* per-clause OIDs of btree opfamilies */
	Oid		   *mergeCollations;	/* per-clause OIDs of collations */
	int		   *mergeStrategies;	/* per-clause ordering (ASC or DESC) */
	bool	   *mergeNullsFirst;	/* per-clause nulls ordering */
} MergeJoin;

/* ----------------
 *		hash join node
 * ----------------
 */
typedef struct HashJoin
{
	Join		join;
	List	   *hashclauses;
} HashJoin;

/* ----------------
 *		materialization node
 * ----------------
 */
typedef struct Material
{
	Plan		plan;
} Material;

/* ----------------
 *		sort node
 * ----------------
 */
typedef struct Sort
{
	Plan		plan;
	int			numCols;		/* number of sort-key columns */
	AttrNumber *sortColIdx;		/* their indexes in the target list */
	Oid		   *sortOperators;	/* OIDs of operators to sort them by */
	Oid		   *collations;		/* OIDs of collations */
	bool	   *nullsFirst;		/* NULLS FIRST/LAST directions */
} Sort;

/* ---------------
 *	 group node -
 *		Used for queries with GROUP BY (but no aggregates) specified.
 *		The input must be presorted according to the grouping columns.
 * ---------------
 */
typedef struct Group
{
	Plan		plan;
	int			numCols;		/* number of grouping columns */
	AttrNumber *grpColIdx;		/* their indexes in the target list */
	Oid		   *grpOperators;	/* equality operators to compare with */
} Group;

/* ---------------
 *		aggregate node
 *
 * An Agg node implements plain or grouped aggregation.  For grouped
 * aggregation, we can work with presorted input or unsorted input;
 * the latter strategy uses an internal hashtable.
 *
 * Notice the lack of any direct info about the aggregate functions to be
 * computed.  They are found by scanning the node's tlist and quals during
 * executor startup.  (It is possible that there are no aggregate functions;
 * this could happen if they get optimized away by constant-folding, or if
 * we are using the Agg node to implement hash-based grouping.)
 * ---------------
 */
typedef enum AggStrategy
{
	AGG_PLAIN,					/* simple agg across all input rows */
	AGG_SORTED,					/* grouped agg, input must be sorted */
	AGG_HASHED					/* grouped agg, use internal hashtable */
} AggStrategy;

typedef struct Agg
{
	Plan		plan;
	AggStrategy aggstrategy;
	int			numCols;		/* number of grouping columns */
	AttrNumber *grpColIdx;		/* their indexes in the target list */
	Oid		   *grpOperators;	/* equality operators to compare with */
	long		numGroups;		/* estimated number of groups in input */
	Bitmapset  *aggParams;		/* IDs of Params used in Aggref inputs */
	/* Note: planner provides numGroups & aggParams only in AGG_HASHED case */
} Agg;

/* ----------------
 *		window aggregate node
 * ----------------
 */
typedef struct WindowAgg
{
	Plan		plan;
	Index		winref;			/* ID referenced by window functions */
	int			partNumCols;	/* number of columns in partition clause */
	AttrNumber *partColIdx;		/* their indexes in the target list */
	Oid		   *partOperators;	/* equality operators for partition columns */
	int			ordNumCols;		/* number of columns in ordering clause */
	AttrNumber *ordColIdx;		/* their indexes in the target list */
	Oid		   *ordOperators;	/* equality operators for ordering columns */
	int			frameOptions;	/* frame_clause options, see WindowDef */
	Node	   *startOffset;	/* expression for starting bound, if any */
	Node	   *endOffset;		/* expression for ending bound, if any */
} WindowAgg;

/* ----------------
 *		unique node
 * ----------------
 */
typedef struct Unique
{
	Plan		plan;
	int			numCols;		/* number of columns to check for uniqueness */
	AttrNumber *uniqColIdx;		/* their indexes in the target list */
	Oid		   *uniqOperators;	/* equality operators to compare with */
} Unique;

/* ----------------
 *		hash build node
 *
 * If the executor is supposed to try to apply skew join optimization, then
 * skewTable/skewColumn/skewInherit identify the outer relation's join key
 * column, from which the relevant MCV statistics can be fetched.  Also, its
 * type information is provided to save a lookup.
 * ----------------
 */
typedef struct Hash
{
	Plan		plan;
	Oid			skewTable;		/* outer join key's table OID, or InvalidOid */
	AttrNumber	skewColumn;		/* outer join key's column #, or zero */
	bool		skewInherit;	/* is outer join rel an inheritance tree? */
	Oid			skewColType;	/* datatype of the outer key column */
	int32		skewColTypmod;	/* typmod of the outer key column */
	/* all other info is in the parent HashJoin node */
} Hash;

/* ----------------
 *		setop node
 * ----------------
 */
typedef enum SetOpCmd
{
	SETOPCMD_INTERSECT,
	SETOPCMD_INTERSECT_ALL,
	SETOPCMD_EXCEPT,
	SETOPCMD_EXCEPT_ALL
} SetOpCmd;

typedef enum SetOpStrategy
{
	SETOP_SORTED,				/* input must be sorted */
	SETOP_HASHED				/* use internal hashtable */
} SetOpStrategy;

typedef struct SetOp
{
	Plan		plan;
	SetOpCmd	cmd;			/* what to do */
	SetOpStrategy strategy;		/* how to do it */
	int			numCols;		/* number of columns to check for
								 * duplicate-ness */
	AttrNumber *dupColIdx;		/* their indexes in the target list */
	Oid		   *dupOperators;	/* equality operators to compare with */
	AttrNumber	flagColIdx;		/* where is the flag column, if any */
	int			firstFlag;		/* flag value for first input relation */
	long		numGroups;		/* estimated number of groups in input */
} SetOp;

/* ----------------
 *		lock-rows node
 *
 * rowMarks identifies the rels to be locked by this node; it should be
 * a subset of the rowMarks listed in the top-level PlannedStmt.
 * epqParam is a Param that all scan nodes below this one must depend on.
 * It is used to force re-evaluation of the plan during EvalPlanQual.
 * ----------------
 */
typedef struct LockRows
{
	Plan		plan;
	List	   *rowMarks;		/* a list of PlanRowMark's */
	int			epqParam;		/* ID of Param for EvalPlanQual re-eval */
} LockRows;

/* ----------------
 *		limit node
 *
 * Note: as of Postgres 8.2, the offset and count expressions are expected
 * to yield int8, rather than int4 as before.
 * ----------------
 */
typedef struct Limit
{
	Plan		plan;
	Node	   *limitOffset;	/* OFFSET parameter, or NULL if none */
	Node	   *limitCount;		/* COUNT parameter, or NULL if none */
} Limit;


/*
 * RowMarkType -
 *	  enums for types of row-marking operations
 *
 * When doing UPDATE, DELETE, or SELECT FOR UPDATE/SHARE, we have to uniquely
 * identify all the source rows, not only those from the target relations, so
 * that we can perform EvalPlanQual rechecking at need.  For plain tables we
 * can just fetch the TID, the same as for a target relation.  Otherwise (for
 * example for VALUES or FUNCTION scans) we have to copy the whole row value.
 * The latter is pretty inefficient but fortunately the case is not
 * performance-critical in practice.
 */
typedef enum RowMarkType
{
	ROW_MARK_EXCLUSIVE,			/* obtain exclusive tuple lock */
	ROW_MARK_SHARE,				/* obtain shared tuple lock */
	ROW_MARK_REFERENCE,			/* just fetch the TID */
	ROW_MARK_COPY				/* physically copy the row value */
} RowMarkType;

#define RowMarkRequiresRowShareLock(marktype)  ((marktype) <= ROW_MARK_SHARE)

/*
 * PlanRowMark -
 *	   plan-time representation of FOR UPDATE/SHARE clauses
 *
 * When doing UPDATE, DELETE, or SELECT FOR UPDATE/SHARE, we create a separate
 * PlanRowMark node for each non-target relation in the query.  Relations that
 * are not specified as FOR UPDATE/SHARE are marked ROW_MARK_REFERENCE (if
 * real tables) or ROW_MARK_COPY (if not).
 *
 * Initially all PlanRowMarks have rti == prti and isParent == false.
 * When the planner discovers that a relation is the root of an inheritance
 * tree, it sets isParent true, and adds an additional PlanRowMark to the
 * list for each child relation (including the target rel itself in its role
 * as a child).  The child entries have rti == child rel's RT index and
 * prti == parent's RT index, and can therefore be recognized as children by
 * the fact that prti != rti.
 *
 * The planner also adds resjunk output columns to the plan that carry
 * information sufficient to identify the locked or fetched rows.  For
 * tables (markType != ROW_MARK_COPY), these columns are named
 *		tableoid%u			OID of table
 *		ctid%u				TID of row
 * The tableoid column is only present for an inheritance hierarchy.
 * When markType == ROW_MARK_COPY, there is instead a single column named
 *		wholerow%u			whole-row value of relation
 * In all three cases, %u represents the rowmark ID number (rowmarkId).
 * This number is unique within a plan tree, except that child relation
 * entries copy their parent's rowmarkId.  (Assigning unique numbers
 * means we needn't renumber rowmarkIds when flattening subqueries, which
 * would require finding and renaming the resjunk columns as well.)
 * Note this means that all tables in an inheritance hierarchy share the
 * same resjunk column names.  However, in an inherited UPDATE/DELETE the
 * columns could have different physical column numbers in each subplan.
 */
typedef struct PlanRowMark
{
	NodeTag		type;
	Index		rti;			/* range table index of markable relation */
	Index		prti;			/* range table index of parent relation */
	Index		rowmarkId;		/* unique identifier for resjunk columns */
	RowMarkType markType;		/* see enum above */
	bool		noWait;			/* NOWAIT option */
	bool		isParent;		/* true if this is a "dummy" parent entry */
} PlanRowMark;


/*
 * Plan invalidation info
 *
 * We track the objects on which a PlannedStmt depends in two ways:
 * relations are recorded as a simple list of OIDs, and everything else
 * is represented as a list of PlanInvalItems.  A PlanInvalItem is designed
 * to be used with the syscache invalidation mechanism, so it identifies a
 * system catalog entry by cache ID and hash value.
 */
typedef struct PlanInvalItem
{
	NodeTag		type;
	int			cacheId;		/* a syscache ID, see utils/syscache.h */
	uint32		hashValue;		/* hash value of object's cache lookup key */
} PlanInvalItem;

#endif   /* PLANNODES_H */
Name	Size	Permission
bitmapset.h	3440 bytes	0644
execnodes.h	66326 bytes	0644
makefuncs.h	2380 bytes	0644
memnodes.h	2614 bytes	0644
nodeFuncs.h	2510 bytes	0644
nodes.h	14692 bytes	0644
params.h	3780 bytes	0644
parsenodes.h	89043 bytes	0644
pg_list.h	11770 bytes	0644
plannodes.h	28273 bytes	0644
primnodes.h	51245 bytes	0644
print.h	1070 bytes	0644
readfuncs.h	897 bytes	0644
relation.h	69763 bytes	0644
replnodes.h	1053 bytes	0644
tidbitmap.h	2239 bytes	0644
value.h	1799 bytes	0644
File Content: plannodes.h

File Content: `plannodes.h`
