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/*-------------------------------------------------------------------------
*
* plannodes.h
* definitions for query plan nodes
*
*
* Portions Copyright (c) 1996-2011, 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"
#include "storage/itemptr.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 */
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 */
IntoClause *intoClause; /* target for SELECT INTO / CREATE TABLE AS */
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 (varattno is the index column
* position, not the base table's column, even though varno is for the base
* table). This is a bit hokey ... would be cleaner to use a special-purpose
* node type that could not be mistaken for a regular Var. But it will do
* for now.
*
* 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.)
* ----------------
*/
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;
/* ----------------
* 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.
*
* Note: subrtable is used just to carry the subquery rangetable from
* createplan.c to setrefs.c; it should always be NIL by the time the
* executor sees the plan. Similarly for subrowmark.
* ----------------
*/
typedef struct SubqueryScan
{
Scan scan;
Plan *subplan;
List *subrtable; /* temporary workspace for planner */
List *subrowmark; /* temporary workspace for planner */
} 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
* ----------------
*/
typedef struct ForeignScan
{
Scan scan;
bool fsSystemCol; /* true if any "system column" is needed */
/* use struct pointer to avoid including fdwapi.h here */
struct FdwPlan *fdwplan;
} 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.
* ----------------
*/
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 */
} 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 tuple TID.
*/
typedef struct PlanInvalItem
{
NodeTag type;
int cacheId; /* a syscache ID, see utils/syscache.h */
ItemPointerData tupleId; /* TID of the object's catalog tuple */
} PlanInvalItem;
#endif /* PLANNODES_H */