/*-------------------------------------------------------------------------
*
* pathnodes.h
* Definitions for planner's internal data structures, especially Paths.
*
* We don't support copying RelOptInfo, IndexOptInfo, or Path nodes.
* There are some subsidiary structs that are useful to copy, though.
*
* Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/nodes/pathnodes.h
*
*-------------------------------------------------------------------------
*/
#ifndef PATHNODES_H
#define PATHNODES_H
#include "access/sdir.h"
#include "lib/stringinfo.h"
#include "nodes/params.h"
#include "nodes/parsenodes.h"
#include "storage/block.h"
/*
* Relids
* Set of relation identifiers (indexes into the rangetable).
*/
typedef Bitmapset *Relids;
/*
* When looking for a "cheapest path", this enum specifies whether we want
* cheapest startup cost or cheapest total cost.
*/
typedef enum CostSelector
{
STARTUP_COST, TOTAL_COST
} CostSelector;
/*
* The cost estimate produced by cost_qual_eval() includes both a one-time
* (startup) cost, and a per-tuple cost.
*/
typedef struct QualCost
{
Cost startup; /* one-time cost */
Cost per_tuple; /* per-evaluation cost */
} QualCost;
/*
* Costing aggregate function execution requires these statistics about
* the aggregates to be executed by a given Agg node. Note that the costs
* include the execution costs of the aggregates' argument expressions as
* well as the aggregate functions themselves. Also, the fields must be
* defined so that initializing the struct to zeroes with memset is correct.
*/
typedef struct AggClauseCosts
{
QualCost transCost; /* total per-input-row execution costs */
QualCost finalCost; /* total per-aggregated-row costs */
Size transitionSpace; /* space for pass-by-ref transition data */
} AggClauseCosts;
/*
* This enum identifies the different types of "upper" (post-scan/join)
* relations that we might deal with during planning.
*/
typedef enum UpperRelationKind
{
UPPERREL_SETOP, /* result of UNION/INTERSECT/EXCEPT, if any */
UPPERREL_PARTIAL_GROUP_AGG, /* result of partial grouping/aggregation, if
* any */
UPPERREL_GROUP_AGG, /* result of grouping/aggregation, if any */
UPPERREL_WINDOW, /* result of window functions, if any */
UPPERREL_PARTIAL_DISTINCT, /* result of partial "SELECT DISTINCT", if any */
UPPERREL_DISTINCT, /* result of "SELECT DISTINCT", if any */
UPPERREL_ORDERED, /* result of ORDER BY, if any */
UPPERREL_FINAL /* result of any remaining top-level actions */
/* NB: UPPERREL_FINAL must be last enum entry; it's used to size arrays */
} UpperRelationKind;
/*----------
* PlannerGlobal
* Global information for planning/optimization
*
* PlannerGlobal holds state for an entire planner invocation; this state
* is shared across all levels of sub-Queries that exist in the command being
* planned.
*
* Not all fields are printed. (In some cases, there is no print support for
* the field type; in others, doing so would lead to infinite recursion.)
*----------
*/
typedef struct PlannerGlobal
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
/* Param values provided to planner() */
ParamListInfo boundParams pg_node_attr(read_write_ignore);
/* Plans for SubPlan nodes */
List *subplans;
/* PlannerInfos for SubPlan nodes */
List *subroots pg_node_attr(read_write_ignore);
/* indices of subplans that require REWIND */
Bitmapset *rewindPlanIDs;
/* "flat" rangetable for executor */
List *finalrtable;
/* "flat" list of RTEPermissionInfos */
List *finalrteperminfos;
/* "flat" list of PlanRowMarks */
List *finalrowmarks;
/* "flat" list of integer RT indexes */
List *resultRelations;
/* "flat" list of AppendRelInfos */
List *appendRelations;
/* OIDs of relations the plan depends on */
List *relationOids;
/* other dependencies, as PlanInvalItems */
List *invalItems;
/* type OIDs for PARAM_EXEC Params */
List *paramExecTypes;
/* highest PlaceHolderVar ID assigned */
Index lastPHId;
/* highest PlanRowMark ID assigned */
Index lastRowMarkId;
/* highest plan node ID assigned */
int lastPlanNodeId;
/* redo plan when TransactionXmin changes? */
bool transientPlan;
/* is plan specific to current role? */
bool dependsOnRole;
/* parallel mode potentially OK? */
bool parallelModeOK;
/* parallel mode actually required? */
bool parallelModeNeeded;
/* worst PROPARALLEL hazard level */
char maxParallelHazard;
/* partition descriptors */
PartitionDirectory partition_directory pg_node_attr(read_write_ignore);
} PlannerGlobal;
/* macro for fetching the Plan associated with a SubPlan node */
#define planner_subplan_get_plan(root, subplan) \
((Plan *) list_nth((root)->glob->subplans, (subplan)->plan_id - 1))
/*----------
* PlannerInfo
* Per-query information for planning/optimization
*
* This struct is conventionally called "root" in all the planner routines.
* It holds links to all of the planner's working state, in addition to the
* original Query. Note that at present the planner extensively modifies
* the passed-in Query data structure; someday that should stop.
*
* For reasons explained in optimizer/optimizer.h, we define the typedef
* either here or in that header, whichever is read first.
*
* Not all fields are printed. (In some cases, there is no print support for
* the field type; in others, doing so would lead to infinite recursion or
* bloat dump output more than seems useful.)
*----------
*/
#ifndef HAVE_PLANNERINFO_TYPEDEF
typedef struct PlannerInfo PlannerInfo;
#define HAVE_PLANNERINFO_TYPEDEF 1
#endif
struct PlannerInfo
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
/* the Query being planned */
Query *parse;
/* global info for current planner run */
PlannerGlobal *glob;
/* 1 at the outermost Query */
Index query_level;
/* NULL at outermost Query */
PlannerInfo *parent_root pg_node_attr(read_write_ignore);
/*
* plan_params contains the expressions that this query level needs to
* make available to a lower query level that is currently being planned.
* outer_params contains the paramIds of PARAM_EXEC Params that outer
* query levels will make available to this query level.
*/
/* list of PlannerParamItems, see below */
List *plan_params;
Bitmapset *outer_params;
/*
* simple_rel_array holds pointers to "base rels" and "other rels" (see
* comments for RelOptInfo for more info). It is indexed by rangetable
* index (so entry 0 is always wasted). Entries can be NULL when an RTE
* does not correspond to a base relation, such as a join RTE or an
* unreferenced view RTE; or if the RelOptInfo hasn't been made yet.
*/
struct RelOptInfo **simple_rel_array pg_node_attr(array_size(simple_rel_array_size));
/* allocated size of array */
int simple_rel_array_size;
/*
* simple_rte_array is the same length as simple_rel_array and holds
* pointers to the associated rangetable entries. Using this is a shade
* faster than using rt_fetch(), mostly due to fewer indirections. (Not
* printed because it'd be redundant with parse->rtable.)
*/
RangeTblEntry **simple_rte_array pg_node_attr(read_write_ignore);
/*
* append_rel_array is the same length as the above arrays, and holds
* pointers to the corresponding AppendRelInfo entry indexed by
* child_relid, or NULL if the rel is not an appendrel child. The array
* itself is not allocated if append_rel_list is empty. (Not printed
* because it'd be redundant with append_rel_list.)
*/
struct AppendRelInfo **append_rel_array pg_node_attr(read_write_ignore);
/*
* all_baserels is a Relids set of all base relids (but not joins or
* "other" rels) in the query. This is computed in deconstruct_jointree.
*/
Relids all_baserels;
/*
* outer_join_rels is a Relids set of all outer-join relids in the query.
* This is computed in deconstruct_jointree.
*/
Relids outer_join_rels;
/*
* all_query_rels is a Relids set of all base relids and outer join relids
* (but not "other" relids) in the query. This is the Relids identifier
* of the final join we need to form. This is computed in
* deconstruct_jointree.
*/
Relids all_query_rels;
/*
* join_rel_list is a list of all join-relation RelOptInfos we have
* considered in this planning run. For small problems we just scan the
* list to do lookups, but when there are many join relations we build a
* hash table for faster lookups. The hash table is present and valid
* when join_rel_hash is not NULL. Note that we still maintain the list
* even when using the hash table for lookups; this simplifies life for
* GEQO.
*/
List *join_rel_list;
struct HTAB *join_rel_hash pg_node_attr(read_write_ignore);
/*
* When doing a dynamic-programming-style join search, join_rel_level[k]
* is a list of all join-relation RelOptInfos of level k, and
* join_cur_level is the current level. New join-relation RelOptInfos are
* automatically added to the join_rel_level[join_cur_level] list.
* join_rel_level is NULL if not in use.
*
* Note: we've already printed all baserel and joinrel RelOptInfos above,
* so we don't dump join_rel_level or other lists of RelOptInfos.
*/
/* lists of join-relation RelOptInfos */
List **join_rel_level pg_node_attr(read_write_ignore);
/* index of list being extended */
int join_cur_level;
/* init SubPlans for query */
List *init_plans;
/*
* per-CTE-item list of subplan IDs (or -1 if no subplan was made for that
* CTE)
*/
List *cte_plan_ids;
/* List of Lists of Params for MULTIEXPR subquery outputs */
List *multiexpr_params;
/* list of JoinDomains used in the query (higher ones first) */
List *join_domains;
/* list of active EquivalenceClasses */
List *eq_classes;
/* set true once ECs are canonical */
bool ec_merging_done;
/* list of "canonical" PathKeys */
List *canon_pathkeys;
/*
* list of OuterJoinClauseInfos for mergejoinable outer join clauses
* w/nonnullable var on left
*/
List *left_join_clauses;
/*
* list of OuterJoinClauseInfos for mergejoinable outer join clauses
* w/nonnullable var on right
*/
List *right_join_clauses;
/*
* list of OuterJoinClauseInfos for mergejoinable full join clauses
*/
List *full_join_clauses;
/* list of SpecialJoinInfos */
List *join_info_list;
/* counter for assigning RestrictInfo serial numbers */
int last_rinfo_serial;
/*
* all_result_relids is empty for SELECT, otherwise it contains at least
* parse->resultRelation. For UPDATE/DELETE/MERGE across an inheritance
* or partitioning tree, the result rel's child relids are added. When
* using multi-level partitioning, intermediate partitioned rels are
* included. leaf_result_relids is similar except that only actual result
* tables, not partitioned tables, are included in it.
*/
/* set of all result relids */
Relids all_result_relids;
/* set of all leaf relids */
Relids leaf_result_relids;
/*
* list of AppendRelInfos
*
* Note: for AppendRelInfos describing partitions of a partitioned table,
* we guarantee that partitions that come earlier in the partitioned
* table's PartitionDesc will appear earlier in append_rel_list.
*/
List *append_rel_list;
/* list of RowIdentityVarInfos */
List *row_identity_vars;
/* list of PlanRowMarks */
List *rowMarks;
/* list of PlaceHolderInfos */
List *placeholder_list;
/* array of PlaceHolderInfos indexed by phid */
struct PlaceHolderInfo **placeholder_array pg_node_attr(read_write_ignore, array_size(placeholder_array_size));
/* allocated size of array */
int placeholder_array_size pg_node_attr(read_write_ignore);
/* list of ForeignKeyOptInfos */
List *fkey_list;
/* desired pathkeys for query_planner() */
List *query_pathkeys;
/* groupClause pathkeys, if any */
List *group_pathkeys;
/*
* The number of elements in the group_pathkeys list which belong to the
* GROUP BY clause. Additional ones belong to ORDER BY / DISTINCT
* aggregates.
*/
int num_groupby_pathkeys;
/* pathkeys of bottom window, if any */
List *window_pathkeys;
/* distinctClause pathkeys, if any */
List *distinct_pathkeys;
/* sortClause pathkeys, if any */
List *sort_pathkeys;
/* Canonicalised partition schemes used in the query. */
List *part_schemes pg_node_attr(read_write_ignore);
/* RelOptInfos we are now trying to join */
List *initial_rels pg_node_attr(read_write_ignore);
/*
* Upper-rel RelOptInfos. Use fetch_upper_rel() to get any particular
* upper rel.
*/
List *upper_rels[UPPERREL_FINAL + 1] pg_node_attr(read_write_ignore);
/* Result tlists chosen by grouping_planner for upper-stage processing */
struct PathTarget *upper_targets[UPPERREL_FINAL + 1] pg_node_attr(read_write_ignore);
/*
* The fully-processed groupClause is kept here. It differs from
* parse->groupClause in that we remove any items that we can prove
* redundant, so that only the columns named here actually need to be
* compared to determine grouping. Note that it's possible for *all* the
* items to be proven redundant, implying that there is only one group
* containing all the query's rows. Hence, if you want to check whether
* GROUP BY was specified, test for nonempty parse->groupClause, not for
* nonempty processed_groupClause.
*
* Currently, when grouping sets are specified we do not attempt to
* optimize the groupClause, so that processed_groupClause will be
* identical to parse->groupClause.
*/
List *processed_groupClause;
/*
* The fully-processed distinctClause is kept here. It differs from
* parse->distinctClause in that we remove any items that we can prove
* redundant, so that only the columns named here actually need to be
* compared to determine uniqueness. Note that it's possible for *all*
* the items to be proven redundant, implying that there should be only
* one output row. Hence, if you want to check whether DISTINCT was
* specified, test for nonempty parse->distinctClause, not for nonempty
* processed_distinctClause.
*/
List *processed_distinctClause;
/*
* The fully-processed targetlist is kept here. It differs from
* parse->targetList in that (for INSERT) it's been reordered to match the
* target table, and defaults have been filled in. Also, additional
* resjunk targets may be present. preprocess_targetlist() does most of
* that work, but note that more resjunk targets can get added during
* appendrel expansion. (Hence, upper_targets mustn't get set up till
* after that.)
*/
List *processed_tlist;
/*
* For UPDATE, this list contains the target table's attribute numbers to
* which the first N entries of processed_tlist are to be assigned. (Any
* additional entries in processed_tlist must be resjunk.) DO NOT use the
* resnos in processed_tlist to identify the UPDATE target columns.
*/
List *update_colnos;
/*
* Fields filled during create_plan() for use in setrefs.c
*/
/* for GroupingFunc fixup (can't print: array length not known here) */
AttrNumber *grouping_map pg_node_attr(read_write_ignore);
/* List of MinMaxAggInfos */
List *minmax_aggs;
/* context holding PlannerInfo */
MemoryContext planner_cxt pg_node_attr(read_write_ignore);
/* # of pages in all non-dummy tables of query */
Cardinality total_table_pages;
/* tuple_fraction passed to query_planner */
Selectivity tuple_fraction;
/* limit_tuples passed to query_planner */
Cardinality limit_tuples;
/*
* Minimum security_level for quals. Note: qual_security_level is zero if
* there are no securityQuals.
*/
Index qual_security_level;
/* true if any RTEs are RTE_JOIN kind */
bool hasJoinRTEs;
/* true if any RTEs are marked LATERAL */
bool hasLateralRTEs;
/* true if havingQual was non-null */
bool hasHavingQual;
/* true if any RestrictInfo has pseudoconstant = true */
bool hasPseudoConstantQuals;
/* true if we've made any of those */
bool hasAlternativeSubPlans;
/* true once we're no longer allowed to add PlaceHolderInfos */
bool placeholdersFrozen;
/* true if planning a recursive WITH item */
bool hasRecursion;
/*
* Information about aggregates. Filled by preprocess_aggrefs().
*/
/* AggInfo structs */
List *agginfos;
/* AggTransInfo structs */
List *aggtransinfos;
/* number of aggs with DISTINCT/ORDER BY/WITHIN GROUP */
int numOrderedAggs;
/* does any agg not support partial mode? */
bool hasNonPartialAggs;
/* is any partial agg non-serializable? */
bool hasNonSerialAggs;
/*
* These fields are used only when hasRecursion is true:
*/
/* PARAM_EXEC ID for the work table */
int wt_param_id;
/* a path for non-recursive term */
struct Path *non_recursive_path;
/*
* These fields are workspace for createplan.c
*/
/* outer rels above current node */
Relids curOuterRels;
/* not-yet-assigned NestLoopParams */
List *curOuterParams;
/*
* These fields are workspace for setrefs.c. Each is an array
* corresponding to glob->subplans. (We could probably teach
* gen_node_support.pl how to determine the array length, but it doesn't
* seem worth the trouble, so just mark them read_write_ignore.)
*/
bool *isAltSubplan pg_node_attr(read_write_ignore);
bool *isUsedSubplan pg_node_attr(read_write_ignore);
/* optional private data for join_search_hook, e.g., GEQO */
void *join_search_private pg_node_attr(read_write_ignore);
/* Does this query modify any partition key columns? */
bool partColsUpdated;
};
/*
* In places where it's known that simple_rte_array[] must have been prepared
* already, we just index into it to fetch RTEs. In code that might be
* executed before or after entering query_planner(), use this macro.
*/
#define planner_rt_fetch(rti, root) \
((root)->simple_rte_array ? (root)->simple_rte_array[rti] : \
rt_fetch(rti, (root)->parse->rtable))
/*
* If multiple relations are partitioned the same way, all such partitions
* will have a pointer to the same PartitionScheme. A list of PartitionScheme
* objects is attached to the PlannerInfo. By design, the partition scheme
* incorporates only the general properties of the partition method (LIST vs.
* RANGE, number of partitioning columns and the type information for each)
* and not the specific bounds.
*
* We store the opclass-declared input data types instead of the partition key
* datatypes since the former rather than the latter are used to compare
* partition bounds. Since partition key data types and the opclass declared
* input data types are expected to be binary compatible (per ResolveOpClass),
* both of those should have same byval and length properties.
*/
typedef struct PartitionSchemeData
{
char strategy; /* partition strategy */
int16 partnatts; /* number of partition attributes */
Oid *partopfamily; /* OIDs of operator families */
Oid *partopcintype; /* OIDs of opclass declared input data types */
Oid *partcollation; /* OIDs of partitioning collations */
/* Cached information about partition key data types. */
int16 *parttyplen;
bool *parttypbyval;
/* Cached information about partition comparison functions. */
struct FmgrInfo *partsupfunc;
} PartitionSchemeData;
typedef struct PartitionSchemeData *PartitionScheme;
/*----------
* RelOptInfo
* Per-relation information for planning/optimization
*
* For planning purposes, a "base rel" is either a plain relation (a table)
* or the output of a sub-SELECT or function that appears in the range table.
* In either case it is uniquely identified by an RT index. A "joinrel"
* is the joining of two or more base rels. A joinrel is identified by
* the set of RT indexes for its component baserels, along with RT indexes
* for any outer joins it has computed. We create RelOptInfo nodes for each
* baserel and joinrel, and store them in the PlannerInfo's simple_rel_array
* and join_rel_list respectively.
*
* Note that there is only one joinrel for any given set of component
* baserels, no matter what order we assemble them in; so an unordered
* set is the right datatype to identify it with.
*
* We also have "other rels", which are like base rels in that they refer to
* single RT indexes; but they are not part of the join tree, and are given
* a different RelOptKind to identify them.
* Currently the only kind of otherrels are those made for member relations
* of an "append relation", that is an inheritance set or UNION ALL subquery.
* An append relation has a parent RTE that is a base rel, which represents
* the entire append relation. The member RTEs are otherrels. The parent
* is present in the query join tree but the members are not. The member
* RTEs and otherrels are used to plan the scans of the individual tables or
* subqueries of the append set; then the parent baserel is given Append
* and/or MergeAppend paths comprising the best paths for the individual
* member rels. (See comments for AppendRelInfo for more information.)
*
* At one time we also made otherrels to represent join RTEs, for use in
* handling join alias Vars. Currently this is not needed because all join
* alias Vars are expanded to non-aliased form during preprocess_expression.
*
* We also have relations representing joins between child relations of
* different partitioned tables. These relations are not added to
* join_rel_level lists as they are not joined directly by the dynamic
* programming algorithm.
*
* There is also a RelOptKind for "upper" relations, which are RelOptInfos
* that describe post-scan/join processing steps, such as aggregation.
* Many of the fields in these RelOptInfos are meaningless, but their Path
* fields always hold Paths showing ways to do that processing step.
*
* Parts of this data structure are specific to various scan and join
* mechanisms. It didn't seem worth creating new node types for them.
*
* relids - Set of relation identifiers (RT indexes). This is a base
* relation if there is just one, a join relation if more;
* in the join case, RT indexes of any outer joins formed
* at or below this join are included along with baserels
* rows - estimated number of tuples in the relation after restriction
* clauses have been applied (ie, output rows of a plan for it)
* consider_startup - true if there is any value in keeping plain paths for
* this rel on the basis of having cheap startup cost
* consider_param_startup - the same for parameterized paths
* reltarget - Default Path output tlist for this rel; normally contains
* Var and PlaceHolderVar nodes for the values we need to
* output from this relation.
* List is in no particular order, but all rels of an
* appendrel set must use corresponding orders.
* NOTE: in an appendrel child relation, may contain
* arbitrary expressions pulled up from a subquery!
* pathlist - List of Path nodes, one for each potentially useful
* method of generating the relation
* ppilist - ParamPathInfo nodes for parameterized Paths, if any
* cheapest_startup_path - the pathlist member with lowest startup cost
* (regardless of ordering) among the unparameterized paths;
* or NULL if there is no unparameterized path
* cheapest_total_path - the pathlist member with lowest total cost
* (regardless of ordering) among the unparameterized paths;
* or if there is no unparameterized path, the path with lowest
* total cost among the paths with minimum parameterization
* cheapest_unique_path - for caching cheapest path to produce unique
* (no duplicates) output from relation; NULL if not yet requested
* cheapest_parameterized_paths - best paths for their parameterizations;
* always includes cheapest_total_path, even if that's unparameterized
* direct_lateral_relids - rels this rel has direct LATERAL references to
* lateral_relids - required outer rels for LATERAL, as a Relids set
* (includes both direct and indirect lateral references)
*
* If the relation is a base relation it will have these fields set:
*
* relid - RTE index (this is redundant with the relids field, but
* is provided for convenience of access)
* rtekind - copy of RTE's rtekind field
* min_attr, max_attr - range of valid AttrNumbers for rel
* attr_needed - array of bitmapsets indicating the highest joinrel
* in which each attribute is needed; if bit 0 is set then
* the attribute is needed as part of final targetlist
* attr_widths - cache space for per-attribute width estimates;
* zero means not computed yet
* nulling_relids - relids of outer joins that can null this rel
* lateral_vars - lateral cross-references of rel, if any (list of
* Vars and PlaceHolderVars)
* lateral_referencers - relids of rels that reference this one laterally
* (includes both direct and indirect lateral references)
* indexlist - list of IndexOptInfo nodes for relation's indexes
* (always NIL if it's not a table or partitioned table)
* pages - number of disk pages in relation (zero if not a table)
* tuples - number of tuples in relation (not considering restrictions)
* allvisfrac - fraction of disk pages that are marked all-visible
* eclass_indexes - EquivalenceClasses that mention this rel (filled
* only after EC merging is complete)
* subroot - PlannerInfo for subquery (NULL if it's not a subquery)
* subplan_params - list of PlannerParamItems to be passed to subquery
*
* Note: for a subquery, tuples and subroot are not set immediately
* upon creation of the RelOptInfo object; they are filled in when
* set_subquery_pathlist processes the object.
*
* For otherrels that are appendrel members, these fields are filled
* in just as for a baserel, except we don't bother with lateral_vars.
*
* If the relation is either a foreign table or a join of foreign tables that
* all belong to the same foreign server and are assigned to the same user to
* check access permissions as (cf checkAsUser), these fields will be set:
*
* serverid - OID of foreign server, if foreign table (else InvalidOid)
* userid - OID of user to check access as (InvalidOid means current user)
* useridiscurrent - we've assumed that userid equals current user
* fdwroutine - function hooks for FDW, if foreign table (else NULL)
* fdw_private - private state for FDW, if foreign table (else NULL)
*
* Two fields are used to cache knowledge acquired during the join search
* about whether this rel is provably unique when being joined to given other
* relation(s), ie, it can have at most one row matching any given row from
* that join relation. Currently we only attempt such proofs, and thus only
* populate these fields, for base rels; but someday they might be used for
* join rels too:
*
* unique_for_rels - list of Relid sets, each one being a set of other
* rels for which this one has been proven unique
* non_unique_for_rels - list of Relid sets, each one being a set of
* other rels for which we have tried and failed to prove
* this one unique
*
* The presence of the following fields depends on the restrictions
* and joins that the relation participates in:
*
* baserestrictinfo - List of RestrictInfo nodes, containing info about
* each non-join qualification clause in which this relation
* participates (only used for base rels)
* baserestrictcost - Estimated cost of evaluating the baserestrictinfo
* clauses at a single tuple (only used for base rels)
* baserestrict_min_security - Smallest security_level found among
* clauses in baserestrictinfo
* joininfo - List of RestrictInfo nodes, containing info about each
* join clause in which this relation participates (but
* note this excludes clauses that might be derivable from
* EquivalenceClasses)
* has_eclass_joins - flag that EquivalenceClass joins are possible
*
* Note: Keeping a restrictinfo list in the RelOptInfo is useful only for
* base rels, because for a join rel the set of clauses that are treated as
* restrict clauses varies depending on which sub-relations we choose to join.
* (For example, in a 3-base-rel join, a clause relating rels 1 and 2 must be
* treated as a restrictclause if we join {1} and {2 3} to make {1 2 3}; but
* if we join {1 2} and {3} then that clause will be a restrictclause in {1 2}
* and should not be processed again at the level of {1 2 3}.) Therefore,
* the restrictinfo list in the join case appears in individual JoinPaths
* (field joinrestrictinfo), not in the parent relation. But it's OK for
* the RelOptInfo to store the joininfo list, because that is the same
* for a given rel no matter how we form it.
*
* We store baserestrictcost in the RelOptInfo (for base relations) because
* we know we will need it at least once (to price the sequential scan)
* and may need it multiple times to price index scans.
*
* A join relation is considered to be partitioned if it is formed from a
* join of two relations that are partitioned, have matching partitioning
* schemes, and are joined on an equijoin of the partitioning columns.
* Under those conditions we can consider the join relation to be partitioned
* by either relation's partitioning keys, though some care is needed if
* either relation can be forced to null by outer-joining. For example, an
* outer join like (A LEFT JOIN B ON A.a = B.b) may produce rows with B.b
* NULL. These rows may not fit the partitioning conditions imposed on B.
* Hence, strictly speaking, the join is not partitioned by B.b and thus
* partition keys of an outer join should include partition key expressions
* from the non-nullable side only. However, if a subsequent join uses
* strict comparison operators (and all commonly-used equijoin operators are
* strict), the presence of nulls doesn't cause a problem: such rows couldn't
* match anything on the other side and thus they don't create a need to do
* any cross-partition sub-joins. Hence we can treat such values as still
* partitioning the join output for the purpose of additional partitionwise
* joining, so long as a strict join operator is used by the next join.
*
* If the relation is partitioned, these fields will be set:
*
* part_scheme - Partitioning scheme of the relation
* nparts - Number of partitions
* boundinfo - Partition bounds
* partbounds_merged - true if partition bounds are merged ones
* partition_qual - Partition constraint if not the root
* part_rels - RelOptInfos for each partition
* all_partrels - Relids set of all partition relids
* partexprs, nullable_partexprs - Partition key expressions
*
* The partexprs and nullable_partexprs arrays each contain
* part_scheme->partnatts elements. Each of the elements is a list of
* partition key expressions. For partitioned base relations, there is one
* expression in each partexprs element, and nullable_partexprs is empty.
* For partitioned join relations, each base relation within the join
* contributes one partition key expression per partitioning column;
* that expression goes in the partexprs[i] list if the base relation
* is not nullable by this join or any lower outer join, or in the
* nullable_partexprs[i] list if the base relation is nullable.
* Furthermore, FULL JOINs add extra nullable_partexprs expressions
* corresponding to COALESCE expressions of the left and right join columns,
* to simplify matching join clauses to those lists.
*
* Not all fields are printed. (In some cases, there is no print support for
* the field type.)
*----------
*/
/* Bitmask of flags supported by table AMs */
#define AMFLAG_HAS_TID_RANGE (1 << 0)
typedef enum RelOptKind
{
RELOPT_BASEREL,
RELOPT_JOINREL,
RELOPT_OTHER_MEMBER_REL,
RELOPT_OTHER_JOINREL,
RELOPT_UPPER_REL,
RELOPT_OTHER_UPPER_REL
} RelOptKind;
/*
* Is the given relation a simple relation i.e a base or "other" member
* relation?
*/
#define IS_SIMPLE_REL(rel) \
((rel)->reloptkind == RELOPT_BASEREL || \
(rel)->reloptkind == RELOPT_OTHER_MEMBER_REL)
/* Is the given relation a join relation? */
#define IS_JOIN_REL(rel) \
((rel)->reloptkind == RELOPT_JOINREL || \
(rel)->reloptkind == RELOPT_OTHER_JOINREL)
/* Is the given relation an upper relation? */
#define IS_UPPER_REL(rel) \
((rel)->reloptkind == RELOPT_UPPER_REL || \
(rel)->reloptkind == RELOPT_OTHER_UPPER_REL)
/* Is the given relation an "other" relation? */
#define IS_OTHER_REL(rel) \
((rel)->reloptkind == RELOPT_OTHER_MEMBER_REL || \
(rel)->reloptkind == RELOPT_OTHER_JOINREL || \
(rel)->reloptkind == RELOPT_OTHER_UPPER_REL)
typedef struct RelOptInfo
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
RelOptKind reloptkind;
/*
* all relations included in this RelOptInfo; set of base + OJ relids
* (rangetable indexes)
*/
Relids relids;
/*
* size estimates generated by planner
*/
/* estimated number of result tuples */
Cardinality rows;
/*
* per-relation planner control flags
*/
/* keep cheap-startup-cost paths? */
bool consider_startup;
/* ditto, for parameterized paths? */
bool consider_param_startup;
/* consider parallel paths? */
bool consider_parallel;
/*
* default result targetlist for Paths scanning this relation; list of
* Vars/Exprs, cost, width
*/
struct PathTarget *reltarget;
/*
* materialization information
*/
List *pathlist; /* Path structures */
List *ppilist; /* ParamPathInfos used in pathlist */
List *partial_pathlist; /* partial Paths */
struct Path *cheapest_startup_path;
struct Path *cheapest_total_path;
struct Path *cheapest_unique_path;
List *cheapest_parameterized_paths;
/*
* parameterization information needed for both base rels and join rels
* (see also lateral_vars and lateral_referencers)
*/
/* rels directly laterally referenced */
Relids direct_lateral_relids;
/* minimum parameterization of rel */
Relids lateral_relids;
/*
* information about a base rel (not set for join rels!)
*/
Index relid;
/* containing tablespace */
Oid reltablespace;
/* RELATION, SUBQUERY, FUNCTION, etc */
RTEKind rtekind;
/* smallest attrno of rel (often <0) */
AttrNumber min_attr;
/* largest attrno of rel */
AttrNumber max_attr;
/* array indexed [min_attr .. max_attr] */
Relids *attr_needed pg_node_attr(read_write_ignore);
/* array indexed [min_attr .. max_attr] */
int32 *attr_widths pg_node_attr(read_write_ignore);
/* relids of outer joins that can null this baserel */
Relids nulling_relids;
/* LATERAL Vars and PHVs referenced by rel */
List *lateral_vars;
/* rels that reference this baserel laterally */
Relids lateral_referencers;
/* list of IndexOptInfo */
List *indexlist;
/* list of StatisticExtInfo */
List *statlist;
/* size estimates derived from pg_class */
BlockNumber pages;
Cardinality tuples;
double allvisfrac;
/* indexes in PlannerInfo's eq_classes list of ECs that mention this rel */
Bitmapset *eclass_indexes;
PlannerInfo *subroot; /* if subquery */
List *subplan_params; /* if subquery */
/* wanted number of parallel workers */
int rel_parallel_workers;
/* Bitmask of optional features supported by the table AM */
uint32 amflags;
/*
* Information about foreign tables and foreign joins
*/
/* identifies server for the table or join */
Oid serverid;
/* identifies user to check access as; 0 means to check as current user */
Oid userid;
/* join is only valid for current user */
bool useridiscurrent;
/* use "struct FdwRoutine" to avoid including fdwapi.h here */
struct FdwRoutine *fdwroutine pg_node_attr(read_write_ignore);
void *fdw_private pg_node_attr(read_write_ignore);
/*
* cache space for remembering if we have proven this relation unique
*/
/* known unique for these other relid set(s) */
List *unique_for_rels;
/* known not unique for these set(s) */
List *non_unique_for_rels;
/*
* used by various scans and joins:
*/
/* RestrictInfo structures (if base rel) */
List *baserestrictinfo;
/* cost of evaluating the above */
QualCost baserestrictcost;
/* min security_level found in baserestrictinfo */
Index baserestrict_min_security;
/* RestrictInfo structures for join clauses involving this rel */
List *joininfo;
/* T means joininfo is incomplete */
bool has_eclass_joins;
/*
* used by partitionwise joins:
*/
/* consider partitionwise join paths? (if partitioned rel) */
bool consider_partitionwise_join;
/*
* inheritance links, if this is an otherrel (otherwise NULL):
*/
/* Immediate parent relation (dumping it would be too verbose) */
struct RelOptInfo *parent pg_node_attr(read_write_ignore);
/* Topmost parent relation (dumping it would be too verbose) */
struct RelOptInfo *top_parent pg_node_attr(read_write_ignore);
/* Relids of topmost parent (redundant, but handy) */
Relids top_parent_relids;
/*
* used for partitioned relations:
*/
/* Partitioning scheme */
PartitionScheme part_scheme pg_node_attr(read_write_ignore);
/*
* Number of partitions; -1 if not yet set; in case of a join relation 0
* means it's considered unpartitioned
*/
int nparts;
/* Partition bounds */
struct PartitionBoundInfoData *boundinfo pg_node_attr(read_write_ignore);
/* True if partition bounds were created by partition_bounds_merge() */
bool partbounds_merged;
/* Partition constraint, if not the root */
List *partition_qual;
/*
* Array of RelOptInfos of partitions, stored in the same order as bounds
* (don't print, too bulky and duplicative)
*/
struct RelOptInfo **part_rels pg_node_attr(read_write_ignore);
/*
* Bitmap with members acting as indexes into the part_rels[] array to
* indicate which partitions survived partition pruning.
*/
Bitmapset *live_parts;
/* Relids set of all partition relids */
Relids all_partrels;
/*
* These arrays are of length partkey->partnatts, which we don't have at
* hand, so don't try to print
*/
/* Non-nullable partition key expressions */
List **partexprs pg_node_attr(read_write_ignore);
/* Nullable partition key expressions */
List **nullable_partexprs pg_node_attr(read_write_ignore);
} RelOptInfo;
/*
* Is given relation partitioned?
*
* It's not enough to test whether rel->part_scheme is set, because it might
* be that the basic partitioning properties of the input relations matched
* but the partition bounds did not. Also, if we are able to prove a rel
* dummy (empty), we should henceforth treat it as unpartitioned.
*/
#define IS_PARTITIONED_REL(rel) \
((rel)->part_scheme && (rel)->boundinfo && (rel)->nparts > 0 && \
(rel)->part_rels && !IS_DUMMY_REL(rel))
/*
* Convenience macro to make sure that a partitioned relation has all the
* required members set.
*/
#define REL_HAS_ALL_PART_PROPS(rel) \
((rel)->part_scheme && (rel)->boundinfo && (rel)->nparts > 0 && \
(rel)->part_rels && (rel)->partexprs && (rel)->nullable_partexprs)
/*
* IndexOptInfo
* Per-index information for planning/optimization
*
* indexkeys[], indexcollations[] each have ncolumns entries.
* opfamily[], and opcintype[] each have nkeycolumns entries. They do
* not contain any information about included attributes.
*
* sortopfamily[], reverse_sort[], and nulls_first[] have
* nkeycolumns entries, if the index is ordered; but if it is unordered,
* those pointers are NULL.
*
* Zeroes in the indexkeys[] array indicate index columns that are
* expressions; there is one element in indexprs for each such column.
*
* For an ordered index, reverse_sort[] and nulls_first[] describe the
* sort ordering of a forward indexscan; we can also consider a backward
* indexscan, which will generate the reverse ordering.
*
* The indexprs and indpred expressions have been run through
* prepqual.c and eval_const_expressions() for ease of matching to
* WHERE clauses. indpred is in implicit-AND form.
*
* indextlist is a TargetEntry list representing the index columns.
* It provides an equivalent base-relation Var for each simple column,
* and links to the matching indexprs element for each expression column.
*
* While most of these fields are filled when the IndexOptInfo is created
* (by plancat.c), indrestrictinfo and predOK are set later, in
* check_index_predicates().
*/
#ifndef HAVE_INDEXOPTINFO_TYPEDEF
typedef struct IndexOptInfo IndexOptInfo;
#define HAVE_INDEXOPTINFO_TYPEDEF 1
#endif
struct IndexOptInfo
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
/* OID of the index relation */
Oid indexoid;
/* tablespace of index (not table) */
Oid reltablespace;
/* back-link to index's table; don't print, else infinite recursion */
RelOptInfo *rel pg_node_attr(read_write_ignore);
/*
* index-size statistics (from pg_class and elsewhere)
*/
/* number of disk pages in index */
BlockNumber pages;
/* number of index tuples in index */
Cardinality tuples;
/* index tree height, or -1 if unknown */
int tree_height;
/*
* index descriptor information
*/
/* number of columns in index */
int ncolumns;
/* number of key columns in index */
int nkeycolumns;
/*
* table column numbers of index's columns (both key and included
* columns), or 0 for expression columns
*/
int *indexkeys pg_node_attr(array_size(ncolumns));
/* OIDs of collations of index columns */
Oid *indexcollations pg_node_attr(array_size(nkeycolumns));
/* OIDs of operator families for columns */
Oid *opfamily pg_node_attr(array_size(nkeycolumns));
/* OIDs of opclass declared input data types */
Oid *opcintype pg_node_attr(array_size(nkeycolumns));
/* OIDs of btree opfamilies, if orderable. NULL if partitioned index */
Oid *sortopfamily pg_node_attr(array_size(nkeycolumns));
/* is sort order descending? or NULL if partitioned index */
bool *reverse_sort pg_node_attr(array_size(nkeycolumns));
/* do NULLs come first in the sort order? or NULL if partitioned index */
bool *nulls_first pg_node_attr(array_size(nkeycolumns));
/* opclass-specific options for columns */
bytea **opclassoptions pg_node_attr(read_write_ignore);
/* which index cols can be returned in an index-only scan? */
bool *canreturn pg_node_attr(array_size(ncolumns));
/* OID of the access method (in pg_am) */
Oid relam;
/*
* expressions for non-simple index columns; redundant to print since we
* print indextlist
*/
List *indexprs pg_node_attr(read_write_ignore);
/* predicate if a partial index, else NIL */
List *indpred;
/* targetlist representing index columns */
List *indextlist;
/*
* parent relation's baserestrictinfo list, less any conditions implied by
* the index's predicate (unless it's a target rel, see comments in
* check_index_predicates())
*/
List *indrestrictinfo;
/* true if index predicate matches query */
bool predOK;
/* true if a unique index */
bool unique;
/* is uniqueness enforced immediately? */
bool immediate;
/* true if index doesn't really exist */
bool hypothetical;
/*
* Remaining fields are copied from the index AM's API struct
* (IndexAmRoutine). These fields are not set for partitioned indexes.
*/
bool amcanorderbyop;
bool amoptionalkey;
bool amsearcharray;
bool amsearchnulls;
/* does AM have amgettuple interface? */
bool amhasgettuple;
/* does AM have amgetbitmap interface? */
bool amhasgetbitmap;
bool amcanparallel;
/* does AM have ammarkpos interface? */
bool amcanmarkpos;
/* AM's cost estimator */
/* Rather than include amapi.h here, we declare amcostestimate like this */
void (*amcostestimate) () pg_node_attr(read_write_ignore);
};
/*
* ForeignKeyOptInfo
* Per-foreign-key information for planning/optimization
*
* The per-FK-column arrays can be fixed-size because we allow at most
* INDEX_MAX_KEYS columns in a foreign key constraint. Each array has
* nkeys valid entries.
*/
typedef struct ForeignKeyOptInfo
{
pg_node_attr(custom_read_write, no_copy_equal, no_read, no_query_jumble)
NodeTag type;
/*
* Basic data about the foreign key (fetched from catalogs):
*/
/* RT index of the referencing table */
Index con_relid;
/* RT index of the referenced table */
Index ref_relid;
/* number of columns in the foreign key */
int nkeys;
/* cols in referencing table */
AttrNumber conkey[INDEX_MAX_KEYS] pg_node_attr(array_size(nkeys));
/* cols in referenced table */
AttrNumber confkey[INDEX_MAX_KEYS] pg_node_attr(array_size(nkeys));
/* PK = FK operator OIDs */
Oid conpfeqop[INDEX_MAX_KEYS] pg_node_attr(array_size(nkeys));
/*
* Derived info about whether FK's equality conditions match the query:
*/
/* # of FK cols matched by ECs */
int nmatched_ec;
/* # of these ECs that are ec_has_const */
int nconst_ec;
/* # of FK cols matched by non-EC rinfos */
int nmatched_rcols;
/* total # of non-EC rinfos matched to FK */
int nmatched_ri;
/* Pointer to eclass matching each column's condition, if there is one */
struct EquivalenceClass *eclass[INDEX_MAX_KEYS];
/* Pointer to eclass member for the referencing Var, if there is one */
struct EquivalenceMember *fk_eclass_member[INDEX_MAX_KEYS];
/* List of non-EC RestrictInfos matching each column's condition */
List *rinfos[INDEX_MAX_KEYS];
} ForeignKeyOptInfo;
/*
* StatisticExtInfo
* Information about extended statistics for planning/optimization
*
* Each pg_statistic_ext row is represented by one or more nodes of this
* type, or even zero if ANALYZE has not computed them.
*/
typedef struct StatisticExtInfo
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
/* OID of the statistics row */
Oid statOid;
/* includes child relations */
bool inherit;
/* back-link to statistic's table; don't print, else infinite recursion */
RelOptInfo *rel pg_node_attr(read_write_ignore);
/* statistics kind of this entry */
char kind;
/* attnums of the columns covered */
Bitmapset *keys;
/* expressions */
List *exprs;
} StatisticExtInfo;
/*
* JoinDomains
*
* A "join domain" defines the scope of applicability of deductions made via
* the EquivalenceClass mechanism. Roughly speaking, a join domain is a set
* of base+OJ relations that are inner-joined together. More precisely, it is
* the set of relations at which equalities deduced from an EquivalenceClass
* can be enforced or should be expected to hold. The topmost JoinDomain
* covers the whole query (so its jd_relids should equal all_query_rels).
* An outer join creates a new JoinDomain that includes all base+OJ relids
* within its nullable side, but (by convention) not the OJ's own relid.
* A FULL join creates two new JoinDomains, one for each side.
*
* Notice that a rel that is below outer join(s) will thus appear to belong
* to multiple join domains. However, any of its Vars that appear in
* EquivalenceClasses belonging to higher join domains will have nullingrel
* bits preventing them from being evaluated at the rel's scan level, so that
* we will not be able to derive enforceable-at-the-rel-scan-level clauses
* from such ECs. We define the join domain relid sets this way so that
* domains can be said to be "higher" or "lower" when one domain relid set
* includes another.
*
* The JoinDomains for a query are computed in deconstruct_jointree.
* We do not copy JoinDomain structs once made, so they can be compared
* for equality by simple pointer equality.
*/
typedef struct JoinDomain
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
Relids jd_relids; /* all relids contained within the domain */
} JoinDomain;
/*
* EquivalenceClasses
*
* Whenever we identify a mergejoinable equality clause A = B that is
* not an outer-join clause, we create an EquivalenceClass containing
* the expressions A and B to record this knowledge. If we later find another
* equivalence B = C, we add C to the existing EquivalenceClass; this may
* require merging two existing EquivalenceClasses. At the end of the qual
* distribution process, we have sets of values that are known all transitively
* equal to each other, where "equal" is according to the rules of the btree
* operator family(s) shown in ec_opfamilies, as well as the collation shown
* by ec_collation. (We restrict an EC to contain only equalities whose
* operators belong to the same set of opfamilies. This could probably be
* relaxed, but for now it's not worth the trouble, since nearly all equality
* operators belong to only one btree opclass anyway. Similarly, we suppose
* that all or none of the input datatypes are collatable, so that a single
* collation value is sufficient.)
*
* Strictly speaking, deductions from an EquivalenceClass hold only within
* a "join domain", that is a set of relations that are innerjoined together
* (see JoinDomain above). For the most part we don't need to account for
* this explicitly, because equality clauses from different join domains
* will contain Vars that are not equal() because they have different
* nullingrel sets, and thus we will never falsely merge ECs from different
* join domains. But Var-free (pseudoconstant) expressions lack that safety
* feature. We handle that by marking "const" EC members with the JoinDomain
* of the clause they came from; two nominally-equal const members will be
* considered different if they came from different JoinDomains. This ensures
* no false EquivalenceClass merges will occur.
*
* We also use EquivalenceClasses as the base structure for PathKeys, letting
* us represent knowledge about different sort orderings being equivalent.
* Since every PathKey must reference an EquivalenceClass, we will end up
* with single-member EquivalenceClasses whenever a sort key expression has
* not been equivalenced to anything else. It is also possible that such an
* EquivalenceClass will contain a volatile expression ("ORDER BY random()"),
* which is a case that can't arise otherwise since clauses containing
* volatile functions are never considered mergejoinable. We mark such
* EquivalenceClasses specially to prevent them from being merged with
* ordinary EquivalenceClasses. Also, for volatile expressions we have
* to be careful to match the EquivalenceClass to the correct targetlist
* entry: consider SELECT random() AS a, random() AS b ... ORDER BY b,a.
* So we record the SortGroupRef of the originating sort clause.
*
* NB: if ec_merged isn't NULL, this class has been merged into another, and
* should be ignored in favor of using the pointed-to class.
*
* NB: EquivalenceClasses are never copied after creation. Therefore,
* copyObject() copies pointers to them as pointers, and equal() compares
* pointers to EquivalenceClasses via pointer equality. This is implemented
* by putting copy_as_scalar and equal_as_scalar attributes on fields that
* are pointers to EquivalenceClasses. The same goes for EquivalenceMembers.
*/
typedef struct EquivalenceClass
{
pg_node_attr(custom_read_write, no_copy_equal, no_read, no_query_jumble)
NodeTag type;
List *ec_opfamilies; /* btree operator family OIDs */
Oid ec_collation; /* collation, if datatypes are collatable */
List *ec_members; /* list of EquivalenceMembers */
List *ec_sources; /* list of generating RestrictInfos */
List *ec_derives; /* list of derived RestrictInfos */
Relids ec_relids; /* all relids appearing in ec_members, except
* for child members (see below) */
bool ec_has_const; /* any pseudoconstants in ec_members? */
bool ec_has_volatile; /* the (sole) member is a volatile expr */
bool ec_broken; /* failed to generate needed clauses? */
Index ec_sortref; /* originating sortclause label, or 0 */
Index ec_min_security; /* minimum security_level in ec_sources */
Index ec_max_security; /* maximum security_level in ec_sources */
struct EquivalenceClass *ec_merged; /* set if merged into another EC */
} EquivalenceClass;
/*
* If an EC contains a constant, any PathKey depending on it must be
* redundant, since there's only one possible value of the key.
*/
#define EC_MUST_BE_REDUNDANT(eclass) \
((eclass)->ec_has_const)
/*
* EquivalenceMember - one member expression of an EquivalenceClass
*
* em_is_child signifies that this element was built by transposing a member
* for an appendrel parent relation to represent the corresponding expression
* for an appendrel child. These members are used for determining the
* pathkeys of scans on the child relation and for explicitly sorting the
* child when necessary to build a MergeAppend path for the whole appendrel
* tree. An em_is_child member has no impact on the properties of the EC as a
* whole; in particular the EC's ec_relids field does NOT include the child
* relation. An em_is_child member should never be marked em_is_const nor
* cause ec_has_const or ec_has_volatile to be set, either. Thus, em_is_child
* members are not really full-fledged members of the EC, but just reflections
* or doppelgangers of real members. Most operations on EquivalenceClasses
* should ignore em_is_child members, and those that don't should test
* em_relids to make sure they only consider relevant members.
*
* em_datatype is usually the same as exprType(em_expr), but can be
* different when dealing with a binary-compatible opfamily; in particular
* anyarray_ops would never work without this. Use em_datatype when
* looking up a specific btree operator to work with this expression.
*/
typedef struct EquivalenceMember
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
Expr *em_expr; /* the expression represented */
Relids em_relids; /* all relids appearing in em_expr */
bool em_is_const; /* expression is pseudoconstant? */
bool em_is_child; /* derived version for a child relation? */
Oid em_datatype; /* the "nominal type" used by the opfamily */
JoinDomain *em_jdomain; /* join domain containing the source clause */
/* if em_is_child is true, this links to corresponding EM for top parent */
struct EquivalenceMember *em_parent pg_node_attr(read_write_ignore);
} EquivalenceMember;
/*
* PathKeys
*
* The sort ordering of a path is represented by a list of PathKey nodes.
* An empty list implies no known ordering. Otherwise the first item
* represents the primary sort key, the second the first secondary sort key,
* etc. The value being sorted is represented by linking to an
* EquivalenceClass containing that value and including pk_opfamily among its
* ec_opfamilies. The EquivalenceClass tells which collation to use, too.
* This is a convenient method because it makes it trivial to detect
* equivalent and closely-related orderings. (See optimizer/README for more
* information.)
*
* Note: pk_strategy is either BTLessStrategyNumber (for ASC) or
* BTGreaterStrategyNumber (for DESC). We assume that all ordering-capable
* index types will use btree-compatible strategy numbers.
*/
typedef struct PathKey
{
pg_node_attr(no_read, no_query_jumble)
NodeTag type;
/* the value that is ordered */
EquivalenceClass *pk_eclass pg_node_attr(copy_as_scalar, equal_as_scalar);
Oid pk_opfamily; /* btree opfamily defining the ordering */
int pk_strategy; /* sort direction (ASC or DESC) */
bool pk_nulls_first; /* do NULLs come before normal values? */
} PathKey;
/*
* VolatileFunctionStatus -- allows nodes to cache their
* contain_volatile_functions properties. VOLATILITY_UNKNOWN means not yet
* determined.
*/
typedef enum VolatileFunctionStatus
{
VOLATILITY_UNKNOWN = 0,
VOLATILITY_VOLATILE,
VOLATILITY_NOVOLATILE
} VolatileFunctionStatus;
/*
* PathTarget
*
* This struct contains what we need to know during planning about the
* targetlist (output columns) that a Path will compute. Each RelOptInfo
* includes a default PathTarget, which its individual Paths may simply
* reference. However, in some cases a Path may compute outputs different
* from other Paths, and in that case we make a custom PathTarget for it.
* For example, an indexscan might return index expressions that would
* otherwise need to be explicitly calculated. (Note also that "upper"
* relations generally don't have useful default PathTargets.)
*
* exprs contains bare expressions; they do not have TargetEntry nodes on top,
* though those will appear in finished Plans.
*
* sortgrouprefs[] is an array of the same length as exprs, containing the
* corresponding sort/group refnos, or zeroes for expressions not referenced
* by sort/group clauses. If sortgrouprefs is NULL (which it generally is in
* RelOptInfo.reltarget targets; only upper-level Paths contain this info),
* we have not identified sort/group columns in this tlist. This allows us to
* deal with sort/group refnos when needed with less expense than including
* TargetEntry nodes in the exprs list.
*/
typedef struct PathTarget
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
/* list of expressions to be computed */
List *exprs;
/* corresponding sort/group refnos, or 0 */
Index *sortgrouprefs pg_node_attr(array_size(exprs));
/* cost of evaluating the expressions */
QualCost cost;
/* estimated avg width of result tuples */
int width;
/* indicates if exprs contain any volatile functions */
VolatileFunctionStatus has_volatile_expr;
} PathTarget;
/* Convenience macro to get a sort/group refno from a PathTarget */
#define get_pathtarget_sortgroupref(target, colno) \
((target)->sortgrouprefs ? (target)->sortgrouprefs[colno] : (Index) 0)
/*
* ParamPathInfo
*
* All parameterized paths for a given relation with given required outer rels
* link to a single ParamPathInfo, which stores common information such as
* the estimated rowcount for this parameterization. We do this partly to
* avoid recalculations, but mostly to ensure that the estimated rowcount
* is in fact the same for every such path.
*
* Note: ppi_clauses is only used in ParamPathInfos for base relation paths;
* in join cases it's NIL because the set of relevant clauses varies depending
* on how the join is formed. The relevant clauses will appear in each
* parameterized join path's joinrestrictinfo list, instead. ParamPathInfos
* for append relations don't bother with this, either.
*
* ppi_serials is the set of rinfo_serial numbers for quals that are enforced
* by this path. As with ppi_clauses, it's only maintained for baserels.
* (We could construct it on-the-fly from ppi_clauses, but it seems better
* to materialize a copy.)
*/
typedef struct ParamPathInfo
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
Relids ppi_req_outer; /* rels supplying parameters used by path */
Cardinality ppi_rows; /* estimated number of result tuples */
List *ppi_clauses; /* join clauses available from outer rels */
Bitmapset *ppi_serials; /* set of rinfo_serial for enforced quals */
} ParamPathInfo;
/*
* Type "Path" is used as-is for sequential-scan paths, as well as some other
* simple plan types that we don't need any extra information in the path for.
* For other path types it is the first component of a larger struct.
*
* "pathtype" is the NodeTag of the Plan node we could build from this Path.
* It is partially redundant with the Path's NodeTag, but allows us to use
* the same Path type for multiple Plan types when there is no need to
* distinguish the Plan type during path processing.
*
* "parent" identifies the relation this Path scans, and "pathtarget"
* describes the precise set of output columns the Path would compute.
* In simple cases all Paths for a given rel share the same targetlist,
* which we represent by having path->pathtarget equal to parent->reltarget.
*
* "param_info", if not NULL, links to a ParamPathInfo that identifies outer
* relation(s) that provide parameter values to each scan of this path.
* That means this path can only be joined to those rels by means of nestloop
* joins with this path on the inside. Also note that a parameterized path
* is responsible for testing all "movable" joinclauses involving this rel
* and the specified outer rel(s).
*
* "rows" is the same as parent->rows in simple paths, but in parameterized
* paths and UniquePaths it can be less than parent->rows, reflecting the
* fact that we've filtered by extra join conditions or removed duplicates.
*
* "pathkeys" is a List of PathKey nodes (see above), describing the sort
* ordering of the path's output rows.
*
* We do not support copying Path trees, mainly because the circular linkages
* between RelOptInfo and Path nodes can't be handled easily in a simple
* depth-first traversal. We also don't have read support at the moment.
*/
typedef struct Path
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
/* tag identifying scan/join method */
NodeTag pathtype;
/*
* the relation this path can build
*
* We do NOT print the parent, else we'd be in infinite recursion. We can
* print the parent's relids for identification purposes, though.
*/
RelOptInfo *parent pg_node_attr(write_only_relids);
/*
* list of Vars/Exprs, cost, width
*
* We print the pathtarget only if it's not the default one for the rel.
*/
PathTarget *pathtarget pg_node_attr(write_only_nondefault_pathtarget);
/*
* parameterization info, or NULL if none
*
* We do not print the whole of param_info, since it's printed via
* RelOptInfo; it's sufficient and less cluttering to print just the
* required outer relids.
*/
ParamPathInfo *param_info pg_node_attr(write_only_req_outer);
/* engage parallel-aware logic? */
bool parallel_aware;
/* OK to use as part of parallel plan? */
bool parallel_safe;
/* desired # of workers; 0 = not parallel */
int parallel_workers;
/* estimated size/costs for path (see costsize.c for more info) */
Cardinality rows; /* estimated number of result tuples */
Cost startup_cost; /* cost expended before fetching any tuples */
Cost total_cost; /* total cost (assuming all tuples fetched) */
/* sort ordering of path's output; a List of PathKey nodes; see above */
List *pathkeys;
} Path;
/* Macro for extracting a path's parameterization relids; beware double eval */
#define PATH_REQ_OUTER(path) \
((path)->param_info ? (path)->param_info->ppi_req_outer : (Relids) NULL)
/*----------
* IndexPath represents an index scan over a single index.
*
* This struct is used for both regular indexscans and index-only scans;
* path.pathtype is T_IndexScan or T_IndexOnlyScan to show which is meant.
*
* 'indexinfo' is the index to be scanned.
*
* 'indexclauses' is a list of IndexClause nodes, each representing one
* index-checkable restriction, with implicit AND semantics across the list.
* An empty list implies a full index scan.
*
* 'indexorderbys', if not NIL, is a list of ORDER BY expressions that have
* been found to be usable as ordering operators for an amcanorderbyop index.
* The list must match the path's pathkeys, ie, one expression per pathkey
* in the same order. These are not RestrictInfos, just bare expressions,
* since they generally won't yield booleans. It's guaranteed that each
* expression has the index key on the left side of the operator.
*
* 'indexorderbycols' is an integer list of index column numbers (zero-based)
* of the same length as 'indexorderbys', showing which index column each
* ORDER BY expression is meant to be used with. (There is no restriction
* on which index column each ORDER BY can be used with.)
*
* 'indexscandir' is one of:
* ForwardScanDirection: forward scan of an index
* BackwardScanDirection: backward scan of an ordered index
* Unordered indexes will always have an indexscandir of ForwardScanDirection.
*
* 'indextotalcost' and 'indexselectivity' are saved in the IndexPath so that
* we need not recompute them when considering using the same index in a
* bitmap index/heap scan (see BitmapHeapPath). The costs of the IndexPath
* itself represent the costs of an IndexScan or IndexOnlyScan plan type.
*----------
*/
typedef struct IndexPath
{
Path path;
IndexOptInfo *indexinfo;
List *indexclauses;
List *indexorderbys;
List *indexorderbycols;
ScanDirection indexscandir;
Cost indextotalcost;
Selectivity indexselectivity;
} IndexPath;
/*
* Each IndexClause references a RestrictInfo node from the query's WHERE
* or JOIN conditions, and shows how that restriction can be applied to
* the particular index. We support both indexclauses that are directly
* usable by the index machinery, which are typically of the form
* "indexcol OP pseudoconstant", and those from which an indexable qual
* can be derived. The simplest such transformation is that a clause
* of the form "pseudoconstant OP indexcol" can be commuted to produce an
* indexable qual (the index machinery expects the indexcol to be on the
* left always). Another example is that we might be able to extract an
* indexable range condition from a LIKE condition, as in "x LIKE 'foo%bar'"
* giving rise to "x >= 'foo' AND x < 'fop'". Derivation of such lossy
* conditions is done by a planner support function attached to the
* indexclause's top-level function or operator.
*
* indexquals is a list of RestrictInfos for the directly-usable index
* conditions associated with this IndexClause. In the simplest case
* it's a one-element list whose member is iclause->rinfo. Otherwise,
* it contains one or more directly-usable indexqual conditions extracted
* from the given clause. The 'lossy' flag indicates whether the
* indexquals are semantically equivalent to the original clause, or
* represent a weaker condition.
*
* Normally, indexcol is the index of the single index column the clause
* works on, and indexcols is NIL. But if the clause is a RowCompareExpr,
* indexcol is the index of the leading column, and indexcols is a list of
* all the affected columns. (Note that indexcols matches up with the
* columns of the actual indexable RowCompareExpr in indexquals, which
* might be different from the original in rinfo.)
*
* An IndexPath's IndexClause list is required to be ordered by index
* column, i.e. the indexcol values must form a nondecreasing sequence.
* (The order of multiple clauses for the same index column is unspecified.)
*/
typedef struct IndexClause
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
struct RestrictInfo *rinfo; /* original restriction or join clause */
List *indexquals; /* indexqual(s) derived from it */
bool lossy; /* are indexquals a lossy version of clause? */
AttrNumber indexcol; /* index column the clause uses (zero-based) */
List *indexcols; /* multiple index columns, if RowCompare */
} IndexClause;
/*
* BitmapHeapPath represents one or more indexscans that generate TID bitmaps
* instead of directly accessing the heap, followed by AND/OR combinations
* to produce a single bitmap, followed by a heap scan that uses the bitmap.
* Note that the output is always considered unordered, since it will come
* out in physical heap order no matter what the underlying indexes did.
*
* The individual indexscans are represented by IndexPath nodes, and any
* logic on top of them is represented by a tree of BitmapAndPath and
* BitmapOrPath nodes. Notice that we can use the same IndexPath node both
* to represent a regular (or index-only) index scan plan, and as the child
* of a BitmapHeapPath that represents scanning the same index using a
* BitmapIndexScan. The startup_cost and total_cost figures of an IndexPath
* always represent the costs to use it as a regular (or index-only)
* IndexScan. The costs of a BitmapIndexScan can be computed using the
* IndexPath's indextotalcost and indexselectivity.
*/
typedef struct BitmapHeapPath
{
Path path;
Path *bitmapqual; /* IndexPath, BitmapAndPath, BitmapOrPath */
} BitmapHeapPath;
/*
* BitmapAndPath represents a BitmapAnd plan node; it can only appear as
* part of the substructure of a BitmapHeapPath. The Path structure is
* a bit more heavyweight than we really need for this, but for simplicity
* we make it a derivative of Path anyway.
*/
typedef struct BitmapAndPath
{
Path path;
List *bitmapquals; /* IndexPaths and BitmapOrPaths */
Selectivity bitmapselectivity;
} BitmapAndPath;
/*
* BitmapOrPath represents a BitmapOr plan node; it can only appear as
* part of the substructure of a BitmapHeapPath. The Path structure is
* a bit more heavyweight than we really need for this, but for simplicity
* we make it a derivative of Path anyway.
*/
typedef struct BitmapOrPath
{
Path path;
List *bitmapquals; /* IndexPaths and BitmapAndPaths */
Selectivity bitmapselectivity;
} BitmapOrPath;
/*
* TidPath represents a scan by TID
*
* 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 TidPath
{
Path path;
List *tidquals; /* qual(s) involving CTID = something */
} TidPath;
/*
* TidRangePath represents a scan by a contiguous range of TIDs
*
* tidrangequals is an implicitly AND'ed list of qual expressions of the form
* "CTID relop pseudoconstant", where relop is one of >,>=,<,<=.
*/
typedef struct TidRangePath
{
Path path;
List *tidrangequals;
} TidRangePath;
/*
* SubqueryScanPath represents a scan of an unflattened subquery-in-FROM
*
* Note that the subpath comes from a different planning domain; for example
* RTE indexes within it mean something different from those known to the
* SubqueryScanPath. path.parent->subroot is the planning context needed to
* interpret the subpath.
*/
typedef struct SubqueryScanPath
{
Path path;
Path *subpath; /* path representing subquery execution */
} SubqueryScanPath;
/*
* ForeignPath represents a potential scan of a foreign table, foreign join
* or foreign upper-relation.
*
* fdw_private stores FDW private data about the scan. While fdw_private is
* not actually touched by the core code during normal operations, it's
* generally a good idea to use a representation that can be dumped by
* nodeToString(), so that you can examine the structure during debugging
* with tools like pprint().
*/
typedef struct ForeignPath
{
Path path;
Path *fdw_outerpath;
List *fdw_private;
} ForeignPath;
/*
* CustomPath represents a table scan or a table join done by some out-of-core
* extension.
*
* We provide a set of hooks here - which the provider must take care to set
* up correctly - to allow extensions to supply their own methods of scanning
* a relation or joing relations. For example, a provider might provide GPU
* acceleration, a cache-based scan, or some other kind of logic we haven't
* dreamed up yet.
*
* CustomPaths can be injected into the planning process for a base or join
* relation by set_rel_pathlist_hook or set_join_pathlist_hook functions,
* respectively.
*
* Core code must avoid assuming that the CustomPath is only as large as
* the structure declared here; providers are allowed to make it the first
* element in a larger structure. (Since the planner never copies Paths,
* this doesn't add any complication.) However, for consistency with the
* FDW case, we provide a "custom_private" field in CustomPath; providers
* may prefer to use that rather than define another struct type.
*/
struct CustomPathMethods;
typedef struct CustomPath
{
Path path;
uint32 flags; /* mask of CUSTOMPATH_* flags, see
* nodes/extensible.h */
List *custom_paths; /* list of child Path nodes, if any */
List *custom_private;
const struct CustomPathMethods *methods;
} CustomPath;
/*
* AppendPath represents an Append plan, ie, successive execution of
* several member plans.
*
* For partial Append, 'subpaths' contains non-partial subpaths followed by
* partial subpaths.
*
* Note: it is possible for "subpaths" to contain only one, or even no,
* elements. These cases are optimized during create_append_plan.
* In particular, an AppendPath with no subpaths is a "dummy" path that
* is created to represent the case that a relation is provably empty.
* (This is a convenient representation because it means that when we build
* an appendrel and find that all its children have been excluded, no extra
* action is needed to recognize the relation as dummy.)
*/
typedef struct AppendPath
{
Path path;
List *subpaths; /* list of component Paths */
/* Index of first partial path in subpaths; list_length(subpaths) if none */
int first_partial_path;
Cardinality limit_tuples; /* hard limit on output tuples, or -1 */
} AppendPath;
#define IS_DUMMY_APPEND(p) \
(IsA((p), AppendPath) && ((AppendPath *) (p))->subpaths == NIL)
/*
* A relation that's been proven empty will have one path that is dummy
* (but might have projection paths on top). For historical reasons,
* this is provided as a macro that wraps is_dummy_rel().
*/
#define IS_DUMMY_REL(r) is_dummy_rel(r)
extern bool is_dummy_rel(RelOptInfo *rel);
/*
* MergeAppendPath represents a MergeAppend plan, ie, the merging of sorted
* results from several member plans to produce similarly-sorted output.
*/
typedef struct MergeAppendPath
{
Path path;
List *subpaths; /* list of component Paths */
Cardinality limit_tuples; /* hard limit on output tuples, or -1 */
} MergeAppendPath;
/*
* GroupResultPath represents use of a Result plan node to compute the
* output of a degenerate GROUP BY case, wherein we know we should produce
* exactly one row, which might then be filtered by a HAVING qual.
*
* Note that quals is a list of bare clauses, not RestrictInfos.
*/
typedef struct GroupResultPath
{
Path path;
List *quals;
} GroupResultPath;
/*
* MaterialPath represents use of a Material plan node, i.e., caching of
* the output of its subpath. This is used when the subpath is expensive
* and needs to be scanned repeatedly, or when we need mark/restore ability
* and the subpath doesn't have it.
*/
typedef struct MaterialPath
{
Path path;
Path *subpath;
} MaterialPath;
/*
* MemoizePath represents a Memoize plan node, i.e., a cache that caches
* tuples from parameterized paths to save the underlying node from having to
* be rescanned for parameter values which are already cached.
*/
typedef struct MemoizePath
{
Path path;
Path *subpath; /* outerpath to cache tuples from */
List *hash_operators; /* OIDs of hash equality ops for cache keys */
List *param_exprs; /* expressions that are cache keys */
bool singlerow; /* true if the cache entry is to be marked as
* complete after caching the first record. */
bool binary_mode; /* true when cache key should be compared bit
* by bit, false when using hash equality ops */
Cardinality calls; /* expected number of rescans */
uint32 est_entries; /* The maximum number of entries that the
* planner expects will fit in the cache, or 0
* if unknown */
} MemoizePath;
/*
* UniquePath represents elimination of distinct rows from the output of
* its subpath.
*
* This can represent significantly different plans: either hash-based or
* sort-based implementation, or a no-op if the input path can be proven
* distinct already. The decision is sufficiently localized that it's not
* worth having separate Path node types. (Note: in the no-op case, we could
* eliminate the UniquePath node entirely and just return the subpath; but
* it's convenient to have a UniquePath in the path tree to signal upper-level
* routines that the input is known distinct.)
*/
typedef enum UniquePathMethod
{
UNIQUE_PATH_NOOP, /* input is known unique already */
UNIQUE_PATH_HASH, /* use hashing */
UNIQUE_PATH_SORT /* use sorting */
} UniquePathMethod;
typedef struct UniquePath
{
Path path;
Path *subpath;
UniquePathMethod umethod;
List *in_operators; /* equality operators of the IN clause */
List *uniq_exprs; /* expressions to be made unique */
} UniquePath;
/*
* GatherPath runs several copies of a plan in parallel and collects the
* results. The parallel leader may also execute the plan, unless the
* single_copy flag is set.
*/
typedef struct GatherPath
{
Path path;
Path *subpath; /* path for each worker */
bool single_copy; /* don't execute path more than once */
int num_workers; /* number of workers sought to help */
} GatherPath;
/*
* GatherMergePath runs several copies of a plan in parallel and collects
* the results, preserving their common sort order.
*/
typedef struct GatherMergePath
{
Path path;
Path *subpath; /* path for each worker */
int num_workers; /* number of workers sought to help */
} GatherMergePath;
/*
* All join-type paths share these fields.
*/
typedef struct JoinPath
{
pg_node_attr(abstract)
Path path;
JoinType jointype;
bool inner_unique; /* each outer tuple provably matches no more
* than one inner tuple */
Path *outerjoinpath; /* path for the outer side of the join */
Path *innerjoinpath; /* path for the inner side of the join */
List *joinrestrictinfo; /* RestrictInfos to apply to join */
/*
* See the notes for RelOptInfo and ParamPathInfo to understand why
* joinrestrictinfo is needed in JoinPath, and can't be merged into the
* parent RelOptInfo.
*/
} JoinPath;
/*
* A nested-loop path needs no special fields.
*/
typedef struct NestPath
{
JoinPath jpath;
} NestPath;
/*
* A mergejoin path has these fields.
*
* Unlike other path types, a MergePath node doesn't represent just a single
* run-time plan node: it can represent up to four. Aside from the MergeJoin
* node itself, there can be a Sort node for the outer input, a Sort node
* for the inner input, and/or a Material node for the inner input. We could
* represent these nodes by separate path nodes, but considering how many
* different merge paths are investigated during a complex join problem,
* it seems better to avoid unnecessary palloc overhead.
*
* path_mergeclauses lists the clauses (in the form of RestrictInfos)
* that will be used in the merge.
*
* Note that the mergeclauses are a subset of the parent relation's
* restriction-clause list. Any join clauses that are not mergejoinable
* appear only in the parent's restrict list, and must be checked by a
* qpqual at execution time.
*
* outersortkeys (resp. innersortkeys) is NIL if the outer path
* (resp. inner path) is already ordered appropriately for the
* mergejoin. If it is not NIL then it is a PathKeys list describing
* the ordering that must be created by an explicit Sort node.
*
* skip_mark_restore is true if the executor need not do mark/restore calls.
* Mark/restore overhead is usually required, but can be skipped if we know
* that the executor need find only one match per outer tuple, and that the
* mergeclauses are sufficient to identify a match. In such cases the
* executor can immediately advance the outer relation after processing a
* match, and therefore it need never back up the inner relation.
*
* materialize_inner is true if a Material node should be placed atop the
* inner input. This may appear with or without an inner Sort step.
*/
typedef struct MergePath
{
JoinPath jpath;
List *path_mergeclauses; /* join clauses to be used for merge */
List *outersortkeys; /* keys for explicit sort, if any */
List *innersortkeys; /* keys for explicit sort, if any */
bool skip_mark_restore; /* can executor skip mark/restore? */
bool materialize_inner; /* add Materialize to inner? */
} MergePath;
/*
* A hashjoin path has these fields.
*
* The remarks above for mergeclauses apply for hashclauses as well.
*
* Hashjoin does not care what order its inputs appear in, so we have
* no need for sortkeys.
*/
typedef struct HashPath
{
JoinPath jpath;
List *path_hashclauses; /* join clauses used for hashing */
int num_batches; /* number of batches expected */
Cardinality inner_rows_total; /* total inner rows expected */
} HashPath;
/*
* ProjectionPath represents a projection (that is, targetlist computation)
*
* Nominally, this path node represents using a Result plan node to do a
* projection step. However, if the input plan node supports projection,
* we can just modify its output targetlist to do the required calculations
* directly, and not need a Result. In some places in the planner we can just
* jam the desired PathTarget into the input path node (and adjust its cost
* accordingly), so we don't need a ProjectionPath. But in other places
* it's necessary to not modify the input path node, so we need a separate
* ProjectionPath node, which is marked dummy to indicate that we intend to
* assign the work to the input plan node. The estimated cost for the
* ProjectionPath node will account for whether a Result will be used or not.
*/
typedef struct ProjectionPath
{
Path path;
Path *subpath; /* path representing input source */
bool dummypp; /* true if no separate Result is needed */
} ProjectionPath;
/*
* ProjectSetPath represents evaluation of a targetlist that includes
* set-returning function(s), which will need to be implemented by a
* ProjectSet plan node.
*/
typedef struct ProjectSetPath
{
Path path;
Path *subpath; /* path representing input source */
} ProjectSetPath;
/*
* SortPath represents an explicit sort step
*
* The sort keys are, by definition, the same as path.pathkeys.
*
* Note: the Sort plan node cannot project, so path.pathtarget must be the
* same as the input's pathtarget.
*/
typedef struct SortPath
{
Path path;
Path *subpath; /* path representing input source */
} SortPath;
/*
* IncrementalSortPath represents an incremental sort step
*
* This is like a regular sort, except some leading key columns are assumed
* to be ordered already.
*/
typedef struct IncrementalSortPath
{
SortPath spath;
int nPresortedCols; /* number of presorted columns */
} IncrementalSortPath;
/*
* GroupPath represents grouping (of presorted input)
*
* groupClause represents the columns to be grouped on; the input path
* must be at least that well sorted.
*
* We can also apply a qual to the grouped rows (equivalent of HAVING)
*/
typedef struct GroupPath
{
Path path;
Path *subpath; /* path representing input source */
List *groupClause; /* a list of SortGroupClause's */
List *qual; /* quals (HAVING quals), if any */
} GroupPath;
/*
* UpperUniquePath represents adjacent-duplicate removal (in presorted input)
*
* The columns to be compared are the first numkeys columns of the path's
* pathkeys. The input is presumed already sorted that way.
*/
typedef struct UpperUniquePath
{
Path path;
Path *subpath; /* path representing input source */
int numkeys; /* number of pathkey columns to compare */
} UpperUniquePath;
/*
* AggPath represents generic computation of aggregate functions
*
* This may involve plain grouping (but not grouping sets), using either
* sorted or hashed grouping; for the AGG_SORTED case, the input must be
* appropriately presorted.
*/
typedef struct AggPath
{
Path path;
Path *subpath; /* path representing input source */
AggStrategy aggstrategy; /* basic strategy, see nodes.h */
AggSplit aggsplit; /* agg-splitting mode, see nodes.h */
Cardinality numGroups; /* estimated number of groups in input */
uint64 transitionSpace; /* for pass-by-ref transition data */
List *groupClause; /* a list of SortGroupClause's */
List *qual; /* quals (HAVING quals), if any */
} AggPath;
/*
* Various annotations used for grouping sets in the planner.
*/
typedef struct GroupingSetData
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
List *set; /* grouping set as list of sortgrouprefs */
Cardinality numGroups; /* est. number of result groups */
} GroupingSetData;
typedef struct RollupData
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
List *groupClause; /* applicable subset of parse->groupClause */
List *gsets; /* lists of integer indexes into groupClause */
List *gsets_data; /* list of GroupingSetData */
Cardinality numGroups; /* est. number of result groups */
bool hashable; /* can be hashed */
bool is_hashed; /* to be implemented as a hashagg */
} RollupData;
/*
* GroupingSetsPath represents a GROUPING SETS aggregation
*/
typedef struct GroupingSetsPath
{
Path path;
Path *subpath; /* path representing input source */
AggStrategy aggstrategy; /* basic strategy */
List *rollups; /* list of RollupData */
List *qual; /* quals (HAVING quals), if any */
uint64 transitionSpace; /* for pass-by-ref transition data */
} GroupingSetsPath;
/*
* MinMaxAggPath represents computation of MIN/MAX aggregates from indexes
*/
typedef struct MinMaxAggPath
{
Path path;
List *mmaggregates; /* list of MinMaxAggInfo */
List *quals; /* HAVING quals, if any */
} MinMaxAggPath;
/*
* WindowAggPath represents generic computation of window functions
*/
typedef struct WindowAggPath
{
Path path;
Path *subpath; /* path representing input source */
WindowClause *winclause; /* WindowClause we'll be using */
List *qual; /* lower-level WindowAgg runconditions */
bool topwindow; /* false for all apart from the WindowAgg
* that's closest to the root of the plan */
} WindowAggPath;
/*
* SetOpPath represents a set-operation, that is INTERSECT or EXCEPT
*/
typedef struct SetOpPath
{
Path path;
Path *subpath; /* path representing input source */
SetOpCmd cmd; /* what to do, see nodes.h */
SetOpStrategy strategy; /* how to do it, see nodes.h */
List *distinctList; /* SortGroupClauses identifying target cols */
AttrNumber flagColIdx; /* where is the flag column, if any */
int firstFlag; /* flag value for first input relation */
Cardinality numGroups; /* estimated number of groups in input */
} SetOpPath;
/*
* RecursiveUnionPath represents a recursive UNION node
*/
typedef struct RecursiveUnionPath
{
Path path;
Path *leftpath; /* paths representing input sources */
Path *rightpath;
List *distinctList; /* SortGroupClauses identifying target cols */
int wtParam; /* ID of Param representing work table */
Cardinality numGroups; /* estimated number of groups in input */
} RecursiveUnionPath;
/*
* LockRowsPath represents acquiring row locks for SELECT FOR UPDATE/SHARE
*/
typedef struct LockRowsPath
{
Path path;
Path *subpath; /* path representing input source */
List *rowMarks; /* a list of PlanRowMark's */
int epqParam; /* ID of Param for EvalPlanQual re-eval */
} LockRowsPath;
/*
* ModifyTablePath represents performing INSERT/UPDATE/DELETE/MERGE
*
* We represent most things that will be in the ModifyTable plan node
* literally, except we have a child Path not Plan. But analysis of the
* OnConflictExpr is deferred to createplan.c, as is collection of FDW data.
*/
typedef struct ModifyTablePath
{
Path path;
Path *subpath; /* Path producing source data */
CmdType operation; /* INSERT, UPDATE, DELETE, or MERGE */
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 partitioned/inherited */
bool partColsUpdated; /* some part key in hierarchy updated? */
List *resultRelations; /* integer list of RT indexes */
List *updateColnosLists; /* per-target-table update_colnos lists */
List *withCheckOptionLists; /* per-target-table WCO lists */
List *returningLists; /* per-target-table RETURNING tlists */
List *rowMarks; /* PlanRowMarks (non-locking only) */
OnConflictExpr *onconflict; /* ON CONFLICT clause, or NULL */
int epqParam; /* ID of Param for EvalPlanQual re-eval */
List *mergeActionLists; /* per-target-table lists of actions for
* MERGE */
} ModifyTablePath;
/*
* LimitPath represents applying LIMIT/OFFSET restrictions
*/
typedef struct LimitPath
{
Path path;
Path *subpath; /* path representing input source */
Node *limitOffset; /* OFFSET parameter, or NULL if none */
Node *limitCount; /* COUNT parameter, or NULL if none */
LimitOption limitOption; /* FETCH FIRST with ties or exact number */
} LimitPath;
/*
* Restriction clause info.
*
* We create one of these for each AND sub-clause of a restriction condition
* (WHERE or JOIN/ON clause). Since the restriction clauses are logically
* ANDed, we can use any one of them or any subset of them to filter out
* tuples, without having to evaluate the rest. The RestrictInfo node itself
* stores data used by the optimizer while choosing the best query plan.
*
* If a restriction clause references a single base relation, it will appear
* in the baserestrictinfo list of the RelOptInfo for that base rel.
*
* If a restriction clause references more than one base+OJ relation, it will
* appear in the joininfo list of every RelOptInfo that describes a strict
* subset of the relations mentioned in the clause. The joininfo lists are
* used to drive join tree building by selecting plausible join candidates.
* The clause cannot actually be applied until we have built a join rel
* containing all the relations it references, however.
*
* When we construct a join rel that includes all the relations referenced
* in a multi-relation restriction clause, we place that clause into the
* joinrestrictinfo lists of paths for the join rel, if neither left nor
* right sub-path includes all relations referenced in the clause. The clause
* will be applied at that join level, and will not propagate any further up
* the join tree. (Note: the "predicate migration" code was once intended to
* push restriction clauses up and down the plan tree based on evaluation
* costs, but it's dead code and is unlikely to be resurrected in the
* foreseeable future.)
*
* Note that in the presence of more than two rels, a multi-rel restriction
* might reach different heights in the join tree depending on the join
* sequence we use. So, these clauses cannot be associated directly with
* the join RelOptInfo, but must be kept track of on a per-join-path basis.
*
* RestrictInfos that represent equivalence conditions (i.e., mergejoinable
* equalities that are not outerjoin-delayed) are handled a bit differently.
* Initially we attach them to the EquivalenceClasses that are derived from
* them. When we construct a scan or join path, we look through all the
* EquivalenceClasses and generate derived RestrictInfos representing the
* minimal set of conditions that need to be checked for this particular scan
* or join to enforce that all members of each EquivalenceClass are in fact
* equal in all rows emitted by the scan or join.
*
* The clause_relids field lists the base plus outer-join RT indexes that
* actually appear in the clause. required_relids lists the minimum set of
* relids needed to evaluate the clause; while this is often equal to
* clause_relids, it can be more. We will add relids to required_relids when
* we need to force an outer join ON clause to be evaluated exactly at the
* level of the outer join, which is true except when it is a "degenerate"
* condition that references only Vars from the nullable side of the join.
*
* RestrictInfo nodes contain a flag to indicate whether a qual has been
* pushed down to a lower level than its original syntactic placement in the
* join tree would suggest. If an outer join prevents us from pushing a qual
* down to its "natural" semantic level (the level associated with just the
* base rels used in the qual) then we mark the qual with a "required_relids"
* value including more than just the base rels it actually uses. By
* pretending that the qual references all the rels required to form the outer
* join, we prevent it from being evaluated below the outer join's joinrel.
* When we do form the outer join's joinrel, we still need to distinguish
* those quals that are actually in that join's JOIN/ON condition from those
* that appeared elsewhere in the tree and were pushed down to the join rel
* because they used no other rels. That's what the is_pushed_down flag is
* for; it tells us that a qual is not an OUTER JOIN qual for the set of base
* rels listed in required_relids. A clause that originally came from WHERE
* or an INNER JOIN condition will *always* have its is_pushed_down flag set.
* It's possible for an OUTER JOIN clause to be marked is_pushed_down too,
* if we decide that it can be pushed down into the nullable side of the join.
* In that case it acts as a plain filter qual for wherever it gets evaluated.
* (In short, is_pushed_down is only false for non-degenerate outer join
* conditions. Possibly we should rename it to reflect that meaning? But
* see also the comments for RINFO_IS_PUSHED_DOWN, below.)
*
* There is also an incompatible_relids field, which is a set of outer-join
* relids above which we cannot evaluate the clause (because they might null
* Vars it uses that should not be nulled yet). In principle this could be
* filled in any RestrictInfo as the set of OJ relids that appear above the
* clause and null Vars that it uses. In practice we only bother to populate
* it for "clone" clauses, as it's currently only needed to prevent multiple
* clones of the same clause from being accepted for evaluation at the same
* join level.
*
* There is also an outer_relids field, which is NULL except for outer join
* clauses; for those, it is the set of relids on the outer side of the
* clause's outer join. (These are rels that the clause cannot be applied to
* in parameterized scans, since pushing it into the join's outer side would
* lead to wrong answers.)
*
* To handle security-barrier conditions efficiently, we mark RestrictInfo
* nodes with a security_level field, in which higher values identify clauses
* coming from less-trusted sources. The exact semantics are that a clause
* cannot be evaluated before another clause with a lower security_level value
* unless the first clause is leakproof. As with outer-join clauses, this
* creates a reason for clauses to sometimes need to be evaluated higher in
* the join tree than their contents would suggest; and even at a single plan
* node, this rule constrains the order of application of clauses.
*
* In general, the referenced clause might be arbitrarily complex. The
* kinds of clauses we can handle as indexscan quals, mergejoin clauses,
* or hashjoin clauses are limited (e.g., no volatile functions). The code
* for each kind of path is responsible for identifying the restrict clauses
* it can use and ignoring the rest. Clauses not implemented by an indexscan,
* mergejoin, or hashjoin will be placed in the plan qual or joinqual field
* of the finished Plan node, where they will be enforced by general-purpose
* qual-expression-evaluation code. (But we are still entitled to count
* their selectivity when estimating the result tuple count, if we
* can guess what it is...)
*
* When the referenced clause is an OR clause, we generate a modified copy
* in which additional RestrictInfo nodes are inserted below the top-level
* OR/AND structure. This is a convenience for OR indexscan processing:
* indexquals taken from either the top level or an OR subclause will have
* associated RestrictInfo nodes.
*
* The can_join flag is set true if the clause looks potentially useful as
* a merge or hash join clause, that is if it is a binary opclause with
* nonoverlapping sets of relids referenced in the left and right sides.
* (Whether the operator is actually merge or hash joinable isn't checked,
* however.)
*
* The pseudoconstant flag is set true if the clause contains no Vars of
* the current query level and no volatile functions. Such a clause can be
* pulled out and used as a one-time qual in a gating Result node. We keep
* pseudoconstant clauses in the same lists as other RestrictInfos so that
* the regular clause-pushing machinery can assign them to the correct join
* level, but they need to be treated specially for cost and selectivity
* estimates. Note that a pseudoconstant clause can never be an indexqual
* or merge or hash join clause, so it's of no interest to large parts of
* the planner.
*
* When we generate multiple versions of a clause so as to have versions
* that will work after commuting some left joins per outer join identity 3,
* we mark the one with the fewest nullingrels bits with has_clone = true,
* and the rest with is_clone = true. This allows proper filtering of
* these redundant clauses, so that we apply only one version of them.
*
* When join clauses are generated from EquivalenceClasses, there may be
* several equally valid ways to enforce join equivalence, of which we need
* apply only one. We mark clauses of this kind by setting parent_ec to
* point to the generating EquivalenceClass. Multiple clauses with the same
* parent_ec in the same join are redundant.
*
* Most fields are ignored for equality, since they may not be set yet, and
* should be derivable from the clause anyway.
*
* parent_ec, left_ec, right_ec are not printed, lest it lead to infinite
* recursion in plan tree dump.
*/
typedef struct RestrictInfo
{
pg_node_attr(no_read, no_query_jumble)
NodeTag type;
/* the represented clause of WHERE or JOIN */
Expr *clause;
/* true if clause was pushed down in level */
bool is_pushed_down;
/* see comment above */
bool can_join pg_node_attr(equal_ignore);
/* see comment above */
bool pseudoconstant pg_node_attr(equal_ignore);
/* see comment above */
bool has_clone;
bool is_clone;
/* true if known to contain no leaked Vars */
bool leakproof pg_node_attr(equal_ignore);
/* indicates if clause contains any volatile functions */
VolatileFunctionStatus has_volatile pg_node_attr(equal_ignore);
/* see comment above */
Index security_level;
/* number of base rels in clause_relids */
int num_base_rels pg_node_attr(equal_ignore);
/* The relids (varnos+varnullingrels) actually referenced in the clause: */
Relids clause_relids pg_node_attr(equal_ignore);
/* The set of relids required to evaluate the clause: */
Relids required_relids;
/* Relids above which we cannot evaluate the clause (see comment above) */
Relids incompatible_relids;
/* If an outer-join clause, the outer-side relations, else NULL: */
Relids outer_relids;
/*
* Relids in the left/right side of the clause. These fields are set for
* any binary opclause.
*/
Relids left_relids pg_node_attr(equal_ignore);
Relids right_relids pg_node_attr(equal_ignore);
/*
* Modified clause with RestrictInfos. This field is NULL unless clause
* is an OR clause.
*/
Expr *orclause pg_node_attr(equal_ignore);
/*----------
* Serial number of this RestrictInfo. This is unique within the current
* PlannerInfo context, with a few critical exceptions:
* 1. When we generate multiple clones of the same qual condition to
* cope with outer join identity 3, all the clones get the same serial
* number. This reflects that we only want to apply one of them in any
* given plan.
* 2. If we manufacture a commuted version of a qual to use as an index
* condition, it copies the original's rinfo_serial, since it is in
* practice the same condition.
* 3. RestrictInfos made for a child relation copy their parent's
* rinfo_serial. Likewise, when an EquivalenceClass makes a derived
* equality clause for a child relation, it copies the rinfo_serial of
* the matching equality clause for the parent. This allows detection
* of redundant pushed-down equality clauses.
*----------
*/
int rinfo_serial;
/*
* Generating EquivalenceClass. This field is NULL unless clause is
* potentially redundant.
*/
EquivalenceClass *parent_ec pg_node_attr(copy_as_scalar, equal_ignore, read_write_ignore);
/*
* cache space for cost and selectivity
*/
/* eval cost of clause; -1 if not yet set */
QualCost eval_cost pg_node_attr(equal_ignore);
/* selectivity for "normal" (JOIN_INNER) semantics; -1 if not yet set */
Selectivity norm_selec pg_node_attr(equal_ignore);
/* selectivity for outer join semantics; -1 if not yet set */
Selectivity outer_selec pg_node_attr(equal_ignore);
/*
* opfamilies containing clause operator; valid if clause is
* mergejoinable, else NIL
*/
List *mergeopfamilies pg_node_attr(equal_ignore);
/*
* cache space for mergeclause processing; NULL if not yet set
*/
/* EquivalenceClass containing lefthand */
EquivalenceClass *left_ec pg_node_attr(copy_as_scalar, equal_ignore, read_write_ignore);
/* EquivalenceClass containing righthand */
EquivalenceClass *right_ec pg_node_attr(copy_as_scalar, equal_ignore, read_write_ignore);
/* EquivalenceMember for lefthand */
EquivalenceMember *left_em pg_node_attr(copy_as_scalar, equal_ignore);
/* EquivalenceMember for righthand */
EquivalenceMember *right_em pg_node_attr(copy_as_scalar, equal_ignore);
/*
* List of MergeScanSelCache structs. Those aren't Nodes, so hard to
* copy; instead replace with NIL. That has the effect that copying will
* just reset the cache. Likewise, can't compare or print them.
*/
List *scansel_cache pg_node_attr(copy_as(NIL), equal_ignore, read_write_ignore);
/*
* transient workspace for use while considering a specific join path; T =
* outer var on left, F = on right
*/
bool outer_is_left pg_node_attr(equal_ignore);
/*
* copy of clause operator; valid if clause is hashjoinable, else
* InvalidOid
*/
Oid hashjoinoperator pg_node_attr(equal_ignore);
/*
* cache space for hashclause processing; -1 if not yet set
*/
/* avg bucketsize of left side */
Selectivity left_bucketsize pg_node_attr(equal_ignore);
/* avg bucketsize of right side */
Selectivity right_bucketsize pg_node_attr(equal_ignore);
/* left side's most common val's freq */
Selectivity left_mcvfreq pg_node_attr(equal_ignore);
/* right side's most common val's freq */
Selectivity right_mcvfreq pg_node_attr(equal_ignore);
/* hash equality operators used for memoize nodes, else InvalidOid */
Oid left_hasheqoperator pg_node_attr(equal_ignore);
Oid right_hasheqoperator pg_node_attr(equal_ignore);
} RestrictInfo;
/*
* This macro embodies the correct way to test whether a RestrictInfo is
* "pushed down" to a given outer join, that is, should be treated as a filter
* clause rather than a join clause at that outer join. This is certainly so
* if is_pushed_down is true; but examining that is not sufficient anymore,
* because outer-join clauses will get pushed down to lower outer joins when
* we generate a path for the lower outer join that is parameterized by the
* LHS of the upper one. We can detect such a clause by noting that its
* required_relids exceed the scope of the join.
*/
#define RINFO_IS_PUSHED_DOWN(rinfo, joinrelids) \
((rinfo)->is_pushed_down || \
!bms_is_subset((rinfo)->required_relids, joinrelids))
/*
* Since mergejoinscansel() is a relatively expensive function, and would
* otherwise be invoked many times while planning a large join tree,
* we go out of our way to cache its results. Each mergejoinable
* RestrictInfo carries a list of the specific sort orderings that have
* been considered for use with it, and the resulting selectivities.
*/
typedef struct MergeScanSelCache
{
/* Ordering details (cache lookup key) */
Oid opfamily; /* btree opfamily defining the ordering */
Oid collation; /* collation for the ordering */
int strategy; /* sort direction (ASC or DESC) */
bool nulls_first; /* do NULLs come before normal values? */
/* Results */
Selectivity leftstartsel; /* first-join fraction for clause left side */
Selectivity leftendsel; /* last-join fraction for clause left side */
Selectivity rightstartsel; /* first-join fraction for clause right side */
Selectivity rightendsel; /* last-join fraction for clause right side */
} MergeScanSelCache;
/*
* Placeholder node for an expression to be evaluated below the top level
* of a plan tree. This is used during planning to represent the contained
* expression. At the end of the planning process it is replaced by either
* the contained expression or a Var referring to a lower-level evaluation of
* the contained expression. Generally the evaluation occurs below an outer
* join, and Var references above the outer join might thereby yield NULL
* instead of the expression value.
*
* phrels and phlevelsup correspond to the varno/varlevelsup fields of a
* plain Var, except that phrels has to be a relid set since the evaluation
* level of a PlaceHolderVar might be a join rather than a base relation.
* Likewise, phnullingrels corresponds to varnullingrels.
*
* Although the planner treats this as an expression node type, it is not
* recognized by the parser or executor, so we declare it here rather than
* in primnodes.h.
*
* We intentionally do not compare phexpr. Two PlaceHolderVars with the
* same ID and levelsup should be considered equal even if the contained
* expressions have managed to mutate to different states. This will
* happen during final plan construction when there are nested PHVs, since
* the inner PHV will get replaced by a Param in some copies of the outer
* PHV. Another way in which it can happen is that initplan sublinks
* could get replaced by differently-numbered Params when sublink folding
* is done. (The end result of such a situation would be some
* unreferenced initplans, which is annoying but not really a problem.)
* On the same reasoning, there is no need to examine phrels. But we do
* need to compare phnullingrels, as that represents effects that are
* external to the original value of the PHV.
*/
typedef struct PlaceHolderVar
{
pg_node_attr(no_query_jumble)
Expr xpr;
/* the represented expression */
Expr *phexpr pg_node_attr(equal_ignore);
/* base+OJ relids syntactically within expr src */
Relids phrels pg_node_attr(equal_ignore);
/* RT indexes of outer joins that can null PHV's value */
Relids phnullingrels;
/* ID for PHV (unique within planner run) */
Index phid;
/* > 0 if PHV belongs to outer query */
Index phlevelsup;
} PlaceHolderVar;
/*
* "Special join" info.
*
* One-sided outer joins constrain the order of joining partially but not
* completely. We flatten such joins into the planner's top-level list of
* relations to join, but record information about each outer join in a
* SpecialJoinInfo struct. These structs are kept in the PlannerInfo node's
* join_info_list.
*
* Similarly, semijoins and antijoins created by flattening IN (subselect)
* and EXISTS(subselect) clauses create partial constraints on join order.
* These are likewise recorded in SpecialJoinInfo structs.
*
* We make SpecialJoinInfos for FULL JOINs even though there is no flexibility
* of planning for them, because this simplifies make_join_rel()'s API.
*
* min_lefthand and min_righthand are the sets of base+OJ relids that must be
* available on each side when performing the special join.
* It is not valid for either min_lefthand or min_righthand to be empty sets;
* if they were, this would break the logic that enforces join order.
*
* syn_lefthand and syn_righthand are the sets of base+OJ relids that are
* syntactically below this special join. (These are needed to help compute
* min_lefthand and min_righthand for higher joins.)
*
* jointype is never JOIN_RIGHT; a RIGHT JOIN is handled by switching
* the inputs to make it a LEFT JOIN. It's never JOIN_RIGHT_ANTI either.
* So the allowed values of jointype in a join_info_list member are only
* LEFT, FULL, SEMI, or ANTI.
*
* ojrelid is the RT index of the join RTE representing this outer join,
* if there is one. It is zero when jointype is INNER or SEMI, and can be
* zero for jointype ANTI (if the join was transformed from a SEMI join).
* One use for this field is that when constructing the output targetlist of a
* join relation that implements this OJ, we add ojrelid to the varnullingrels
* and phnullingrels fields of nullable (RHS) output columns, so that the
* output Vars and PlaceHolderVars correctly reflect the nulling that has
* potentially happened to them.
*
* commute_above_l is filled with the relids of syntactically-higher outer
* joins that have been found to commute with this one per outer join identity
* 3 (see optimizer/README), when this join is in the LHS of the upper join
* (so, this is the lower join in the first form of the identity).
*
* commute_above_r is filled with the relids of syntactically-higher outer
* joins that have been found to commute with this one per outer join identity
* 3, when this join is in the RHS of the upper join (so, this is the lower
* join in the second form of the identity).
*
* commute_below_l is filled with the relids of syntactically-lower outer
* joins that have been found to commute with this one per outer join identity
* 3 and are in the LHS of this join (so, this is the upper join in the first
* form of the identity).
*
* commute_below_r is filled with the relids of syntactically-lower outer
* joins that have been found to commute with this one per outer join identity
* 3 and are in the RHS of this join (so, this is the upper join in the second
* form of the identity).
*
* lhs_strict is true if the special join's condition cannot succeed when the
* LHS variables are all NULL (this means that an outer join can commute with
* upper-level outer joins even if it appears in their RHS). We don't bother
* to set lhs_strict for FULL JOINs, however.
*
* For a semijoin, we also extract the join operators and their RHS arguments
* and set semi_operators, semi_rhs_exprs, semi_can_btree, and semi_can_hash.
* This is done in support of possibly unique-ifying the RHS, so we don't
* bother unless at least one of semi_can_btree and semi_can_hash can be set
* true. (You might expect that this information would be computed during
* join planning; but it's helpful to have it available during planning of
* parameterized table scans, so we store it in the SpecialJoinInfo structs.)
*
* For purposes of join selectivity estimation, we create transient
* SpecialJoinInfo structures for regular inner joins; so it is possible
* to have jointype == JOIN_INNER in such a structure, even though this is
* not allowed within join_info_list. We also create transient
* SpecialJoinInfos with jointype == JOIN_INNER for outer joins, since for
* cost estimation purposes it is sometimes useful to know the join size under
* plain innerjoin semantics. Note that lhs_strict and the semi_xxx fields
* are not set meaningfully within such structs.
*/
#ifndef HAVE_SPECIALJOININFO_TYPEDEF
typedef struct SpecialJoinInfo SpecialJoinInfo;
#define HAVE_SPECIALJOININFO_TYPEDEF 1
#endif
struct SpecialJoinInfo
{
pg_node_attr(no_read, no_query_jumble)
NodeTag type;
Relids min_lefthand; /* base+OJ relids in minimum LHS for join */
Relids min_righthand; /* base+OJ relids in minimum RHS for join */
Relids syn_lefthand; /* base+OJ relids syntactically within LHS */
Relids syn_righthand; /* base+OJ relids syntactically within RHS */
JoinType jointype; /* always INNER, LEFT, FULL, SEMI, or ANTI */
Index ojrelid; /* outer join's RT index; 0 if none */
Relids commute_above_l; /* commuting OJs above this one, if LHS */
Relids commute_above_r; /* commuting OJs above this one, if RHS */
Relids commute_below_l; /* commuting OJs in this one's LHS */
Relids commute_below_r; /* commuting OJs in this one's RHS */
bool lhs_strict; /* joinclause is strict for some LHS rel */
/* Remaining fields are set only for JOIN_SEMI jointype: */
bool semi_can_btree; /* true if semi_operators are all btree */
bool semi_can_hash; /* true if semi_operators are all hash */
List *semi_operators; /* OIDs of equality join operators */
List *semi_rhs_exprs; /* righthand-side expressions of these ops */
};
/*
* Transient outer-join clause info.
*
* We set aside every outer join ON clause that looks mergejoinable,
* and process it specially at the end of qual distribution.
*/
typedef struct OuterJoinClauseInfo
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
RestrictInfo *rinfo; /* a mergejoinable outer-join clause */
SpecialJoinInfo *sjinfo; /* the outer join's SpecialJoinInfo */
} OuterJoinClauseInfo;
/*
* Append-relation info.
*
* When we expand an inheritable table or a UNION-ALL subselect into an
* "append relation" (essentially, a list of child RTEs), we build an
* AppendRelInfo for each child RTE. The list of AppendRelInfos indicates
* which child RTEs must be included when expanding the parent, and each node
* carries information needed to translate between columns of the parent and
* columns of the child.
*
* These structs are kept in the PlannerInfo node's append_rel_list, with
* append_rel_array[] providing a convenient lookup method for the struct
* associated with a particular child relid (there can be only one, though
* parent rels may have many entries in append_rel_list).
*
* Note: after completion of the planner prep phase, any given RTE is an
* append parent having entries in append_rel_list if and only if its
* "inh" flag is set. We clear "inh" for plain tables that turn out not
* to have inheritance children, and (in an abuse of the original meaning
* of the flag) we set "inh" for subquery RTEs that turn out to be
* flattenable UNION ALL queries. This lets us avoid useless searches
* of append_rel_list.
*
* Note: the data structure assumes that append-rel members are single
* baserels. This is OK for inheritance, but it prevents us from pulling
* up a UNION ALL member subquery if it contains a join. While that could
* be fixed with a more complex data structure, at present there's not much
* point because no improvement in the plan could result.
*/
typedef struct AppendRelInfo
{
pg_node_attr(no_query_jumble)
NodeTag type;
/*
* These fields uniquely identify this append relationship. There can be
* (in fact, always should be) multiple AppendRelInfos for the same
* parent_relid, but never more than one per child_relid, since a given
* RTE cannot be a child of more than one append parent.
*/
Index parent_relid; /* RT index of append parent rel */
Index child_relid; /* RT index of append child rel */
/*
* For an inheritance appendrel, the parent and child are both regular
* relations, and we store their rowtype OIDs here for use in translating
* whole-row Vars. For a UNION-ALL appendrel, the parent and child are
* both subqueries with no named rowtype, and we store InvalidOid here.
*/
Oid parent_reltype; /* OID of parent's composite type */
Oid child_reltype; /* OID of child's composite type */
/*
* The N'th element of this list is a Var or expression representing the
* child column corresponding to the N'th column of the parent. This is
* used to translate Vars referencing the parent rel into references to
* the child. A list element is NULL if it corresponds to a dropped
* column of the parent (this is only possible for inheritance cases, not
* UNION ALL). The list elements are always simple Vars for inheritance
* cases, but can be arbitrary expressions in UNION ALL cases.
*
* Notice we only store entries for user columns (attno > 0). Whole-row
* Vars are special-cased, and system columns (attno < 0) need no special
* translation since their attnos are the same for all tables.
*
* Caution: the Vars have varlevelsup = 0. Be careful to adjust as needed
* when copying into a subquery.
*/
List *translated_vars; /* Expressions in the child's Vars */
/*
* This array simplifies translations in the reverse direction, from
* child's column numbers to parent's. The entry at [ccolno - 1] is the
* 1-based parent column number for child column ccolno, or zero if that
* child column is dropped or doesn't exist in the parent.
*/
int num_child_cols; /* length of array */
AttrNumber *parent_colnos pg_node_attr(array_size(num_child_cols));
/*
* We store the parent table's OID here for inheritance, or InvalidOid for
* UNION ALL. This is only needed to help in generating error messages if
* an attempt is made to reference a dropped parent column.
*/
Oid parent_reloid; /* OID of parent relation */
} AppendRelInfo;
/*
* Information about a row-identity "resjunk" column in UPDATE/DELETE/MERGE.
*
* In partitioned UPDATE/DELETE/MERGE it's important for child partitions to
* share row-identity columns whenever possible, so as not to chew up too many
* targetlist columns. We use these structs to track which identity columns
* have been requested. In the finished plan, each of these will give rise
* to one resjunk entry in the targetlist of the ModifyTable's subplan node.
*
* All the Vars stored in RowIdentityVarInfos must have varno ROWID_VAR, for
* convenience of detecting duplicate requests. We'll replace that, in the
* final plan, with the varno of the generating rel.
*
* Outside this list, a Var with varno ROWID_VAR and varattno k is a reference
* to the k-th element of the row_identity_vars list (k counting from 1).
* We add such a reference to root->processed_tlist when creating the entry,
* and it propagates into the plan tree from there.
*/
typedef struct RowIdentityVarInfo
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
Var *rowidvar; /* Var to be evaluated (but varno=ROWID_VAR) */
int32 rowidwidth; /* estimated average width */
char *rowidname; /* name of the resjunk column */
Relids rowidrels; /* RTE indexes of target rels using this */
} RowIdentityVarInfo;
/*
* For each distinct placeholder expression generated during planning, we
* store a PlaceHolderInfo node in the PlannerInfo node's placeholder_list.
* This stores info that is needed centrally rather than in each copy of the
* PlaceHolderVar. The phid fields identify which PlaceHolderInfo goes with
* each PlaceHolderVar. Note that phid is unique throughout a planner run,
* not just within a query level --- this is so that we need not reassign ID's
* when pulling a subquery into its parent.
*
* The idea is to evaluate the expression at (only) the ph_eval_at join level,
* then allow it to bubble up like a Var until the ph_needed join level.
* ph_needed has the same definition as attr_needed for a regular Var.
*
* The PlaceHolderVar's expression might contain LATERAL references to vars
* coming from outside its syntactic scope. If so, those rels are *not*
* included in ph_eval_at, but they are recorded in ph_lateral.
*
* Notice that when ph_eval_at is a join rather than a single baserel, the
* PlaceHolderInfo may create constraints on join order: the ph_eval_at join
* has to be formed below any outer joins that should null the PlaceHolderVar.
*
* We create a PlaceHolderInfo only after determining that the PlaceHolderVar
* is actually referenced in the plan tree, so that unreferenced placeholders
* don't result in unnecessary constraints on join order.
*/
typedef struct PlaceHolderInfo
{
pg_node_attr(no_read, no_query_jumble)
NodeTag type;
/* ID for PH (unique within planner run) */
Index phid;
/*
* copy of PlaceHolderVar tree (should be redundant for comparison, could
* be ignored)
*/
PlaceHolderVar *ph_var;
/* lowest level we can evaluate value at */
Relids ph_eval_at;
/* relids of contained lateral refs, if any */
Relids ph_lateral;
/* highest level the value is needed at */
Relids ph_needed;
/* estimated attribute width */
int32 ph_width;
} PlaceHolderInfo;
/*
* This struct describes one potentially index-optimizable MIN/MAX aggregate
* function. MinMaxAggPath contains a list of these, and if we accept that
* path, the list is stored into root->minmax_aggs for use during setrefs.c.
*/
typedef struct MinMaxAggInfo
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
/* pg_proc Oid of the aggregate */
Oid aggfnoid;
/* Oid of its sort operator */
Oid aggsortop;
/* expression we are aggregating on */
Expr *target;
/*
* modified "root" for planning the subquery; not printed, too large, not
* interesting enough
*/
PlannerInfo *subroot pg_node_attr(read_write_ignore);
/* access path for subquery */
Path *path;
/* estimated cost to fetch first row */
Cost pathcost;
/* param for subplan's output */
Param *param;
} MinMaxAggInfo;
/*
* At runtime, PARAM_EXEC slots are used to pass values around from one plan
* node to another. They can be used to pass values down into subqueries (for
* outer references in subqueries), or up out of subqueries (for the results
* of a subplan), or from a NestLoop plan node into its inner relation (when
* the inner scan is parameterized with values from the outer relation).
* The planner is responsible for assigning nonconflicting PARAM_EXEC IDs to
* the PARAM_EXEC Params it generates.
*
* Outer references are managed via root->plan_params, which is a list of
* PlannerParamItems. While planning a subquery, each parent query level's
* plan_params contains the values required from it by the current subquery.
* During create_plan(), we use plan_params to track values that must be
* passed from outer to inner sides of NestLoop plan nodes.
*
* The item a PlannerParamItem represents can be one of three kinds:
*
* A Var: the slot represents a variable of this level that must be passed
* down because subqueries have outer references to it, or must be passed
* from a NestLoop node to its inner scan. The varlevelsup value in the Var
* will always be zero.
*
* A PlaceHolderVar: this works much like the Var case, except that the
* entry is a PlaceHolderVar node with a contained expression. The PHV
* will have phlevelsup = 0, and the contained expression is adjusted
* to match in level.
*
* An Aggref (with an expression tree representing its argument): the slot
* represents an aggregate expression that is an outer reference for some
* subquery. The Aggref itself has agglevelsup = 0, and its argument tree
* is adjusted to match in level.
*
* Note: we detect duplicate Var and PlaceHolderVar parameters and coalesce
* them into one slot, but we do not bother to do that for Aggrefs.
* The scope of duplicate-elimination only extends across the set of
* parameters passed from one query level into a single subquery, or for
* nestloop parameters across the set of nestloop parameters used in a single
* query level. So there is no possibility of a PARAM_EXEC slot being used
* for conflicting purposes.
*
* In addition, PARAM_EXEC slots are assigned for Params representing outputs
* from subplans (values that are setParam items for those subplans). These
* IDs need not be tracked via PlannerParamItems, since we do not need any
* duplicate-elimination nor later processing of the represented expressions.
* Instead, we just record the assignment of the slot number by appending to
* root->glob->paramExecTypes.
*/
typedef struct PlannerParamItem
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
Node *item; /* the Var, PlaceHolderVar, or Aggref */
int paramId; /* its assigned PARAM_EXEC slot number */
} PlannerParamItem;
/*
* When making cost estimates for a SEMI/ANTI/inner_unique join, there are
* some correction factors that are needed in both nestloop and hash joins
* to account for the fact that the executor can stop scanning inner rows
* as soon as it finds a match to the current outer row. These numbers
* depend only on the selected outer and inner join relations, not on the
* particular paths used for them, so it's worthwhile to calculate them
* just once per relation pair not once per considered path. This struct
* is filled by compute_semi_anti_join_factors and must be passed along
* to the join cost estimation functions.
*
* outer_match_frac is the fraction of the outer tuples that are
* expected to have at least one match.
* match_count is the average number of matches expected for
* outer tuples that have at least one match.
*/
typedef struct SemiAntiJoinFactors
{
Selectivity outer_match_frac;
Selectivity match_count;
} SemiAntiJoinFactors;
/*
* Struct for extra information passed to subroutines of add_paths_to_joinrel
*
* restrictlist contains all of the RestrictInfo nodes for restriction
* clauses that apply to this join
* mergeclause_list is a list of RestrictInfo nodes for available
* mergejoin clauses in this join
* inner_unique is true if each outer tuple provably matches no more
* than one inner tuple
* sjinfo is extra info about special joins for selectivity estimation
* semifactors is as shown above (only valid for SEMI/ANTI/inner_unique joins)
* param_source_rels are OK targets for parameterization of result paths
*/
typedef struct JoinPathExtraData
{
List *restrictlist;
List *mergeclause_list;
bool inner_unique;
SpecialJoinInfo *sjinfo;
SemiAntiJoinFactors semifactors;
Relids param_source_rels;
} JoinPathExtraData;
/*
* Various flags indicating what kinds of grouping are possible.
*
* GROUPING_CAN_USE_SORT should be set if it's possible to perform
* sort-based implementations of grouping. When grouping sets are in use,
* this will be true if sorting is potentially usable for any of the grouping
* sets, even if it's not usable for all of them.
*
* GROUPING_CAN_USE_HASH should be set if it's possible to perform
* hash-based implementations of grouping.
*
* GROUPING_CAN_PARTIAL_AGG should be set if the aggregation is of a type
* for which we support partial aggregation (not, for example, grouping sets).
* It says nothing about parallel-safety or the availability of suitable paths.
*/
#define GROUPING_CAN_USE_SORT 0x0001
#define GROUPING_CAN_USE_HASH 0x0002
#define GROUPING_CAN_PARTIAL_AGG 0x0004
/*
* What kind of partitionwise aggregation is in use?
*
* PARTITIONWISE_AGGREGATE_NONE: Not used.
*
* PARTITIONWISE_AGGREGATE_FULL: Aggregate each partition separately, and
* append the results.
*
* PARTITIONWISE_AGGREGATE_PARTIAL: Partially aggregate each partition
* separately, append the results, and then finalize aggregation.
*/
typedef enum
{
PARTITIONWISE_AGGREGATE_NONE,
PARTITIONWISE_AGGREGATE_FULL,
PARTITIONWISE_AGGREGATE_PARTIAL
} PartitionwiseAggregateType;
/*
* Struct for extra information passed to subroutines of create_grouping_paths
*
* flags indicating what kinds of grouping are possible.
* partial_costs_set is true if the agg_partial_costs and agg_final_costs
* have been initialized.
* agg_partial_costs gives partial aggregation costs.
* agg_final_costs gives finalization costs.
* target_parallel_safe is true if target is parallel safe.
* havingQual gives list of quals to be applied after aggregation.
* targetList gives list of columns to be projected.
* patype is the type of partitionwise aggregation that is being performed.
*/
typedef struct
{
/* Data which remains constant once set. */
int flags;
bool partial_costs_set;
AggClauseCosts agg_partial_costs;
AggClauseCosts agg_final_costs;
/* Data which may differ across partitions. */
bool target_parallel_safe;
Node *havingQual;
List *targetList;
PartitionwiseAggregateType patype;
} GroupPathExtraData;
/*
* Struct for extra information passed to subroutines of grouping_planner
*
* limit_needed is true if we actually need a Limit plan node.
* limit_tuples is an estimated bound on the number of output tuples,
* or -1 if no LIMIT or couldn't estimate.
* count_est and offset_est are the estimated values of the LIMIT and OFFSET
* expressions computed by preprocess_limit() (see comments for
* preprocess_limit() for more information).
*/
typedef struct
{
bool limit_needed;
Cardinality limit_tuples;
int64 count_est;
int64 offset_est;
} FinalPathExtraData;
/*
* For speed reasons, cost estimation for join paths is performed in two
* phases: the first phase tries to quickly derive a lower bound for the
* join cost, and then we check if that's sufficient to reject the path.
* If not, we come back for a more refined cost estimate. The first phase
* fills a JoinCostWorkspace struct with its preliminary cost estimates
* and possibly additional intermediate values. The second phase takes
* these values as inputs to avoid repeating work.
*
* (Ideally we'd declare this in cost.h, but it's also needed in pathnode.h,
* so seems best to put it here.)
*/
typedef struct JoinCostWorkspace
{
/* Preliminary cost estimates --- must not be larger than final ones! */
Cost startup_cost; /* cost expended before fetching any tuples */
Cost total_cost; /* total cost (assuming all tuples fetched) */
/* Fields below here should be treated as private to costsize.c */
Cost run_cost; /* non-startup cost components */
/* private for cost_nestloop code */
Cost inner_run_cost; /* also used by cost_mergejoin code */
Cost inner_rescan_run_cost;
/* private for cost_mergejoin code */
Cardinality outer_rows;
Cardinality inner_rows;
Cardinality outer_skip_rows;
Cardinality inner_skip_rows;
/* private for cost_hashjoin code */
int numbuckets;
int numbatches;
Cardinality inner_rows_total;
} JoinCostWorkspace;
/*
* AggInfo holds information about an aggregate that needs to be computed.
* Multiple Aggrefs in a query can refer to the same AggInfo by having the
* same 'aggno' value, so that the aggregate is computed only once.
*/
typedef struct AggInfo
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
/*
* List of Aggref exprs that this state value is for.
*
* There will always be at least one, but there can be multiple identical
* Aggref's sharing the same per-agg.
*/
List *aggrefs;
/* Transition state number for this aggregate */
int transno;
/*
* "shareable" is false if this agg cannot share state values with other
* aggregates because the final function is read-write.
*/
bool shareable;
/* Oid of the final function, or InvalidOid if none */
Oid finalfn_oid;
} AggInfo;
/*
* AggTransInfo holds information about transition state that is used by one
* or more aggregates in the query. Multiple aggregates can share the same
* transition state, if they have the same inputs and the same transition
* function. Aggrefs that share the same transition info have the same
* 'aggtransno' value.
*/
typedef struct AggTransInfo
{
pg_node_attr(no_copy_equal, no_read, no_query_jumble)
NodeTag type;
/* Inputs for this transition state */
List *args;
Expr *aggfilter;
/* Oid of the state transition function */
Oid transfn_oid;
/* Oid of the serialization function, or InvalidOid if none */
Oid serialfn_oid;
/* Oid of the deserialization function, or InvalidOid if none */
Oid deserialfn_oid;
/* Oid of the combine function, or InvalidOid if none */
Oid combinefn_oid;
/* Oid of state value's datatype */
Oid aggtranstype;
/* Additional data about transtype */
int32 aggtranstypmod;
int transtypeLen;
bool transtypeByVal;
/* Space-consumption estimate */
int32 aggtransspace;
/* Initial value from pg_aggregate entry */
Datum initValue pg_node_attr(read_write_ignore);
bool initValueIsNull;
} AggTransInfo;
#endif /* PATHNODES_H */