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/*-------------------------------------------------------------------------
*
* plannodes.h
* definitions for query plan nodes
*
*
* Portions Copyright (c) 1996-2019, 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 "access/stratnum.h"
#include "lib/stringinfo.h"
#include "nodes/bitmapset.h"
#include "nodes/lockoptions.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.
*
* For simplicity in APIs, we also wrap utility statements in PlannedStmt
* nodes; in such cases, commandType == CMD_UTILITY, the statement itself
* is in the utilityStmt field, and the rest of the struct is mostly dummy.
* (We do use canSetTag, stmt_location, stmt_len, and possibly queryId.)
* ----------------
*/
typedef struct PlannedStmt
{
NodeTag type;
CmdType commandType; /* select|insert|update|delete|utility */
uint64 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? */
bool dependsOnRole; /* is plan specific to current role? */
bool parallelModeNeeded; /* parallel mode required to execute? */
int jitFlags; /* which forms of JIT should be performed */
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 */
/*
* rtable indexes of partitioned table roots that are UPDATE/DELETE
* targets; needed for trigger firing.
*/
List *rootResultRelations;
List *subplans; /* Plan trees for SubPlan expressions; note
* that some could be NULL */
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 */
List *paramExecTypes; /* type OIDs for PARAM_EXEC Params */
Node *utilityStmt; /* non-null if this is utility stmt */
/* statement location in source string (copied from Query) */
int stmt_location; /* start location, or -1 if unknown */
int stmt_len; /* length in bytes; 0 means "rest of string" */
} 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 */
/*
* information needed for parallel query
*/
bool parallel_aware; /* engage parallel-aware logic? */
bool parallel_safe; /* OK to use as part of parallel plan? */
/*
* Common structural data for all Plan types.
*/
int plan_node_id; /* unique across entire final plan tree */
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;
/* ----------------
* ProjectSet node -
* Apply a projection that includes set-returning functions to the
* output tuples of the outer plan.
* ----------------
*/
typedef struct ProjectSet
{
Plan plan;
} ProjectSet;
/* ----------------
* ModifyTable node -
* Apply rows produced by subplan(s) to result table(s),
* by inserting, updating, or deleting.
*
* If the originally named target table is a partitioned table, both
* nominalRelation and rootRelation contain the RT index of the partition
* root, which is not otherwise mentioned in the plan. Otherwise rootRelation
* is zero. However, nominalRelation will always be set, as it's the rel that
* EXPLAIN should claim is the INSERT/UPDATE/DELETE target.
*
* 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? */
Index nominalRelation; /* Parent RT index for use of EXPLAIN */
Index rootRelation; /* Root RT index, if target is partitioned */
bool partColsUpdated; /* some part key in hierarchy updated */
List *resultRelations; /* integer list of RT indexes */
int resultRelIndex; /* index of first resultRel in plan's list */
int rootResultRelIndex; /* index of the partitioned table root */
List *plans; /* plan(s) producing source data */
List *withCheckOptionLists; /* per-target-table WCO lists */
List *returningLists; /* per-target-table RETURNING tlists */
List *fdwPrivLists; /* per-target-table FDW private data lists */
Bitmapset *fdwDirectModifyPlans; /* indices of FDW DM plans */
List *rowMarks; /* PlanRowMarks (non-locking only) */
int epqParam; /* ID of Param for EvalPlanQual re-eval */
OnConflictAction onConflictAction; /* ON CONFLICT action */
List *arbiterIndexes; /* List of ON CONFLICT arbiter index OIDs */
List *onConflictSet; /* SET for INSERT ON CONFLICT DO UPDATE */
Node *onConflictWhere; /* WHERE for ON CONFLICT UPDATE */
Index exclRelRTI; /* RTI of the EXCLUDED pseudo relation */
List *exclRelTlist; /* tlist of the EXCLUDED pseudo relation */
} ModifyTable;
struct PartitionPruneInfo; /* forward reference to struct below */
/* ----------------
* Append node -
* Generate the concatenation of the results of sub-plans.
* ----------------
*/
typedef struct Append
{
Plan plan;
List *appendplans;
/*
* All 'appendplans' preceding this index are non-partial plans. All
* 'appendplans' from this index onwards are partial plans.
*/
int first_partial_plan;
/* Info for run-time subplan pruning; NULL if we're not doing that */
struct PartitionPruneInfo *part_prune_info;
} Append;
/* ----------------
* MergeAppend node -
* Merge the results of pre-sorted sub-plans to preserve the ordering.
* ----------------
*/
typedef struct MergeAppend
{
Plan plan;
List *mergeplans;
/* these 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 */
/* Info for run-time subplan pruning; NULL if we're not doing that */
struct PartitionPruneInfo *part_prune_info;
} 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;
bool isshared;
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;
/* ----------------
* table sample scan node
* ----------------
*/
typedef struct SampleScan
{
Scan scan;
/* use struct pointer to avoid including parsenodes.h here */
struct TableSampleClause *tablesample;
} SampleScan;
/* ----------------
* 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 used at runtime to recheck the ordering, if the index
* cannot calculate an accurate ordering. It is also needed for EXPLAIN.
*
* indexorderbyops is a list of the OIDs of the operators used to sort the
* ORDER BY expressions. This is used together with indexorderbyorig to
* recheck ordering at run time. (Note that indexorderby, indexorderbyorig,
* and indexorderbyops are used for amcanorderbyop cases, not amcanorder.)
*
* 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 */
List *indexorderbyops; /* OIDs of sort ops for ORDER BY exprs */
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 */
bool isshared; /* Create shared bitmap if set */
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)",
* or a CurrentOfExpr for the relation.
* ----------------
*/
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;
List *functions; /* list of RangeTblFunction nodes */
bool funcordinality; /* WITH ORDINALITY */
} FunctionScan;
/* ----------------
* ValuesScan node
* ----------------
*/
typedef struct ValuesScan
{
Scan scan;
List *values_lists; /* list of expression lists */
} ValuesScan;
/* ----------------
* TableFunc scan node
* ----------------
*/
typedef struct TableFuncScan
{
Scan scan;
TableFunc *tablefunc; /* table function node */
} TableFuncScan;
/* ----------------
* CteScan node
* ----------------
*/
typedef struct CteScan
{
Scan scan;
int ctePlanId; /* ID of init SubPlan for CTE */
int cteParam; /* ID of Param representing CTE output */
} CteScan;
/* ----------------
* NamedTuplestoreScan node
* ----------------
*/
typedef struct NamedTuplestoreScan
{
Scan scan;
char *enrname; /* Name given to Ephemeral Named Relation */
} NamedTuplestoreScan;
/* ----------------
* 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().
*
* fdw_scan_tlist is a targetlist describing the contents of the scan tuple
* returned by the FDW; it can be NIL if the scan tuple matches the declared
* rowtype of the foreign table, which is the normal case for a simple foreign
* table scan. (If the plan node represents a foreign join, fdw_scan_tlist
* is required since there is no rowtype available from the system catalogs.)
* When fdw_scan_tlist is provided, Vars in the node's tlist and quals must
* have varno INDEX_VAR, and their varattnos correspond to resnos in the
* fdw_scan_tlist (which are also column numbers in the actual scan tuple).
* fdw_scan_tlist is never actually executed; it just holds expression trees
* describing what is in the scan tuple's columns.
*
* fdw_recheck_quals should contain any quals which the core system passed to
* the FDW but which were not added to scan.plan.qual; that is, it should
* contain the quals being checked remotely. This is needed for correct
* behavior during EvalPlanQual rechecks.
*
* When the plan node represents a foreign join, scan.scanrelid is zero and
* fs_relids must be consulted to identify the join relation. (fs_relids
* is valid for simple scans as well, but will always match scan.scanrelid.)
* ----------------
*/
typedef struct ForeignScan
{
Scan scan;
CmdType operation; /* SELECT/INSERT/UPDATE/DELETE */
Oid fs_server; /* OID of foreign server */
List *fdw_exprs; /* expressions that FDW may evaluate */
List *fdw_private; /* private data for FDW */
List *fdw_scan_tlist; /* optional tlist describing scan tuple */
List *fdw_recheck_quals; /* original quals not in scan.plan.qual */
Bitmapset *fs_relids; /* RTIs generated by this scan */
bool fsSystemCol; /* true if any "system column" is needed */
} ForeignScan;
/* ----------------
* CustomScan node
*
* The comments for ForeignScan's fdw_exprs, fdw_private, fdw_scan_tlist,
* and fs_relids fields apply equally to CustomScan's custom_exprs,
* custom_private, custom_scan_tlist, and custom_relids fields. The
* convention of setting scan.scanrelid to zero for joins applies as well.
*
* Note that since Plan trees can be copied, custom scan providers *must*
* fit all plan data they need into those fields; embedding CustomScan in
* a larger struct will not work.
* ----------------
*/
struct CustomScanMethods;
typedef struct CustomScan
{
Scan scan;
uint32 flags; /* mask of CUSTOMPATH_* flags, see
* nodes/extensible.h */
List *custom_plans; /* list of Plan nodes, if any */
List *custom_exprs; /* expressions that custom code may evaluate */
List *custom_private; /* private data for custom code */
List *custom_scan_tlist; /* optional tlist describing scan tuple */
Bitmapset *custom_relids; /* RTIs generated by this scan */
const struct CustomScanMethods *methods;
} CustomScan;
/*
* ==========
* Join nodes
* ==========
*/
/* ----------------
* Join node
*
* jointype: rule for joining tuples from left and right subtrees
* inner_unique each outer tuple can match to no more than one inner tuple
* 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.
*
* inner_unique is set if the joinquals are such that no more than one inner
* tuple could match any given outer tuple. This allows the executor to
* skip searching for additional matches. (This must be provable from just
* the joinquals, ignoring plan.qual, due to where the executor tests it.)
* ----------------
*/
typedef struct Join
{
Plan plan;
JoinType jointype;
bool inner_unique;
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;
bool skip_mark_restore; /* Can we skip mark/restore calls? */
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 struct Agg
{
Plan plan;
AggStrategy aggstrategy; /* basic strategy, see nodes.h */
AggSplit aggsplit; /* agg-splitting mode, see nodes.h */
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 HASHED/MIXED case */
List *groupingSets; /* grouping sets to use */
List *chain; /* chained Agg/Sort nodes */
} 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 */
/* these fields are used with RANGE offset PRECEDING/FOLLOWING: */
Oid startInRangeFunc; /* in_range function for startOffset */
Oid endInRangeFunc; /* in_range function for endOffset */
Oid inRangeColl; /* collation for in_range tests */
bool inRangeAsc; /* use ASC sort order for in_range tests? */
bool inRangeNullsFirst; /* nulls sort first for in_range tests? */
} 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;
/* ------------
* gather node
*
* Note: rescan_param is the ID of a PARAM_EXEC parameter slot. That slot
* will never actually contain a value, but the Gather node must flag it as
* having changed whenever it is rescanned. The child parallel-aware scan
* nodes are marked as depending on that parameter, so that the rescan
* machinery is aware that their output is likely to change across rescans.
* In some cases we don't need a rescan Param, so rescan_param is set to -1.
* ------------
*/
typedef struct Gather
{
Plan plan;
int num_workers; /* planned number of worker processes */
int rescan_param; /* ID of Param that signals a rescan, or -1 */
bool single_copy; /* don't execute plan more than once */
bool invisible; /* suppress EXPLAIN display (for testing)? */
Bitmapset *initParam; /* param id's of initplans which are referred
* at gather or one of it's child node */
} Gather;
/* ------------
* gather merge node
* ------------
*/
typedef struct GatherMerge
{
Plan plan;
int num_workers; /* planned number of worker processes */
int rescan_param; /* ID of Param that signals a rescan, or -1 */
/* 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 */
Bitmapset *initParam; /* param id's of initplans which are referred
* at gather merge or one of it's child node */
} GatherMerge;
/* ----------------
* 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.
* ----------------
*/
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? */
/* all other info is in the parent HashJoin node */
double rows_total; /* estimate total rows if parallel_aware */
} Hash;
/* ----------------
* setop node
* ----------------
*/
typedef struct SetOp
{
Plan plan;
SetOpCmd cmd; /* what to do, see nodes.h */
SetOpStrategy strategy; /* how to do it, see nodes.h */
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
*
* The first four of these values represent different lock strengths that
* we can take on tuples according to SELECT FOR [KEY] UPDATE/SHARE requests.
* We support these on regular tables, as well as on foreign tables whose FDWs
* report support for late locking. For other foreign tables, any locking
* that might be done for such requests must happen during the initial row
* fetch; their FDWs provide no mechanism for going back to lock a row later.
* This means that the semantics will be a bit different than for a local
* table; in particular we are likely to lock more rows than would be locked
* locally, since remote rows will be locked even if they then fail
* locally-checked restriction or join quals. However, the prospect of
* doing a separate remote query to lock each selected row is usually pretty
* unappealing, so early locking remains a credible design choice for FDWs.
*
* 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, much as for a target relation; this case is
* represented by ROW_MARK_REFERENCE. Otherwise (for example for VALUES or
* FUNCTION scans) we have to copy the whole row value. ROW_MARK_COPY is
* pretty inefficient, since most of the time we'll never need the data; but
* fortunately the overhead is usually not performance-critical in practice.
* By default we use ROW_MARK_COPY for foreign tables, but if the FDW has
* a concept of rowid it can request to use ROW_MARK_REFERENCE instead.
* (Again, this probably doesn't make sense if a physical remote fetch is
* needed, but for FDWs that map to local storage it might be credible.)
*/
typedef enum RowMarkType
{
ROW_MARK_EXCLUSIVE, /* obtain exclusive tuple lock */
ROW_MARK_NOKEYEXCLUSIVE, /* obtain no-key exclusive tuple lock */
ROW_MARK_SHARE, /* obtain shared tuple lock */
ROW_MARK_KEYSHARE, /* obtain keyshare tuple lock */
ROW_MARK_REFERENCE, /* just fetch the TID, don't lock it */
ROW_MARK_COPY /* physically copy the row value */
} RowMarkType;
#define RowMarkRequiresRowShareLock(marktype) ((marktype) <= ROW_MARK_KEYSHARE)
/*
* PlanRowMark -
* plan-time representation of FOR [KEY] 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
* regular tables or supported foreign 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). isParent is also set to true for the partitioned child
* relations, which are not scanned just like the root parent. 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 parent's allMarkTypes field gets the OR of (1<<markType) across all
* its children (this definition allows children to use different markTypes).
*
* The planner also adds resjunk output columns to the plan that carry
* information sufficient to identify the locked or fetched rows. When
* 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
* (An inheritance hierarchy could have all three resjunk output columns,
* if some children use a different markType than others.)
* 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 */
int allMarkTypes; /* OR of (1<<markType) for all children */
LockClauseStrength strength; /* LockingClause's strength, or LCS_NONE */
LockWaitPolicy waitPolicy; /* NOWAIT and SKIP LOCKED options */
bool isParent; /* true if this is a "dummy" parent entry */
} PlanRowMark;
/*
* Node types to represent partition pruning information.
*/
/*
* PartitionPruneInfo - Details required to allow the executor to prune
* partitions.
*
* Here we store mapping details to allow translation of a partitioned table's
* index as returned by the partition pruning code into subplan indexes for
* plan types which support arbitrary numbers of subplans, such as Append.
* We also store various details to tell the executor when it should be
* performing partition pruning.
*
* Each PartitionedRelPruneInfo describes the partitioning rules for a single
* partitioned table (a/k/a level of partitioning). Since a partitioning
* hierarchy could contain multiple levels, we represent it by a List of
* PartitionedRelPruneInfos, where the first entry represents the topmost
* partitioned table and additional entries represent non-leaf child
* partitions, ordered such that parents appear before their children.
* Then, since an Append-type node could have multiple partitioning
* hierarchies among its children, we have an unordered List of those Lists.
*
* prune_infos List of Lists containing PartitionedRelPruneInfo nodes,
* one sublist per run-time-prunable partition hierarchy
* appearing in the parent plan node's subplans.
* other_subplans Indexes of any subplans that are not accounted for
* by any of the PartitionedRelPruneInfo nodes in
* "prune_infos". These subplans must not be pruned.
*/
typedef struct PartitionPruneInfo
{
NodeTag type;
List *prune_infos;
Bitmapset *other_subplans;
} PartitionPruneInfo;
/*
* PartitionedRelPruneInfo - Details required to allow the executor to prune
* partitions for a single partitioned table.
*
* subplan_map[] and subpart_map[] are indexed by partition index of the
* partitioned table referenced by 'rtindex', the partition index being the
* order that the partitions are defined in the table's PartitionDesc. For a
* leaf partition p, subplan_map[p] contains the zero-based index of the
* partition's subplan in the parent plan's subplan list; it is -1 if the
* partition is non-leaf or has been pruned. For a non-leaf partition p,
* subpart_map[p] contains the zero-based index of that sub-partition's
* PartitionedRelPruneInfo in the hierarchy's PartitionedRelPruneInfo list;
* it is -1 if the partition is a leaf or has been pruned. Note that subplan
* indexes, as stored in 'subplan_map', are global across the parent plan
* node, but partition indexes are valid only within a particular hierarchy.
*/
typedef struct PartitionedRelPruneInfo
{
NodeTag type;
Index rtindex; /* RT index of partition rel for this level */
List *pruning_steps; /* List of PartitionPruneStep, see below */
Bitmapset *present_parts; /* Indexes of all partitions which subplans or
* subparts are present for. */
int nparts; /* Length of subplan_map[] and subpart_map[] */
int nexprs; /* Length of hasexecparam[] */
int *subplan_map; /* subplan index by partition index, or -1 */
int *subpart_map; /* subpart index by partition index, or -1 */
bool *hasexecparam; /* true if corresponding pruning_step contains
* any PARAM_EXEC Params. */
bool do_initial_prune; /* true if pruning should be performed
* during executor startup. */
bool do_exec_prune; /* true if pruning should be performed during
* executor run. */
Bitmapset *execparamids; /* All PARAM_EXEC Param IDs in pruning_steps */
} PartitionedRelPruneInfo;
/*
* Abstract Node type for partition pruning steps (there are no concrete
* Nodes of this type).
*
* step_id is the global identifier of the step within its pruning context.
*/
typedef struct PartitionPruneStep
{
NodeTag type;
int step_id;
} PartitionPruneStep;
/*
* PartitionPruneStepOp - Information to prune using a set of mutually AND'd
* OpExpr clauses
*
* This contains information extracted from up to partnatts OpExpr clauses,
* where partnatts is the number of partition key columns. 'opstrategy' is the
* strategy of the operator in the clause matched to the last partition key.
* 'exprs' contains expressions which comprise the lookup key to be passed to
* the partition bound search function. 'cmpfns' contains the OIDs of
* comparison functions used to compare aforementioned expressions with
* partition bounds. Both 'exprs' and 'cmpfns' contain the same number of
* items, up to partnatts items.
*
* Once we find the offset of a partition bound using the lookup key, we
* determine which partitions to include in the result based on the value of
* 'opstrategy'. For example, if it were equality, we'd return just the
* partition that would contain that key or a set of partitions if the key
* didn't consist of all partitioning columns. For non-equality strategies,
* we'd need to include other partitions as appropriate.
*
* 'nullkeys' is the set containing the offset of the partition keys (0 to
* partnatts - 1) that were matched to an IS NULL clause. This is only
* considered for hash partitioning as we need to pass which keys are null
* to the hash partition bound search function. It is never possible to
* have an expression be present in 'exprs' for a given partition key and
* the corresponding bit set in 'nullkeys'.
*/
typedef struct PartitionPruneStepOp
{
PartitionPruneStep step;
StrategyNumber opstrategy;
List *exprs;
List *cmpfns;
Bitmapset *nullkeys;
} PartitionPruneStepOp;
/*
* PartitionPruneStepCombine - Information to prune using a BoolExpr clause
*
* For BoolExpr clauses, we combine the set of partitions determined for each
* of the argument clauses.
*/
typedef enum PartitionPruneCombineOp
{
PARTPRUNE_COMBINE_UNION,
PARTPRUNE_COMBINE_INTERSECT
} PartitionPruneCombineOp;
typedef struct PartitionPruneStepCombine
{
PartitionPruneStep step;
PartitionPruneCombineOp combineOp;
List *source_stepids;
} PartitionPruneStepCombine;
/*
* 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 */