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Diffstat (limited to 'src/include/nodes/pathnodes.h')
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diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h new file mode 100644 index 0000000..69150e4 --- /dev/null +++ b/src/include/nodes/pathnodes.h @@ -0,0 +1,2556 @@ +/*------------------------------------------------------------------------- + * + * pathnodes.h + * Definitions for planner's internal data structures, especially Paths. + * + * + * Portions Copyright (c) 1996-2020, 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 +{ + int numAggs; /* total number of aggregate functions */ + int numOrderedAggs; /* number w/ DISTINCT/ORDER BY/WITHIN GROUP */ + bool hasNonPartial; /* does any agg not support partial mode? */ + bool hasNonSerial; /* is any partial agg non-serializable? */ + 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_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; + +/* + * This enum identifies which type of relation is being planned through the + * inheritance planner. INHKIND_NONE indicates the inheritance planner + * was not used. + */ +typedef enum InheritanceKind +{ + INHKIND_NONE, + INHKIND_INHERITED, + INHKIND_PARTITIONED +} InheritanceKind; + +/*---------- + * 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. + *---------- + */ +typedef struct PlannerGlobal +{ + NodeTag type; + + ParamListInfo boundParams; /* Param values provided to planner() */ + + List *subplans; /* Plans for SubPlan nodes */ + + List *subroots; /* PlannerInfos for SubPlan nodes */ + + Bitmapset *rewindPlanIDs; /* indices of subplans that require REWIND */ + + List *finalrtable; /* "flat" rangetable for executor */ + + List *finalrowmarks; /* "flat" list of PlanRowMarks */ + + List *resultRelations; /* "flat" list of integer RT indexes */ + + List *rootResultRelations; /* "flat" list of integer RT indexes */ + + List *appendRelations; /* "flat" list of AppendRelInfos */ + + List *relationOids; /* OIDs of relations the plan depends on */ + + List *invalItems; /* other dependencies, as PlanInvalItems */ + + List *paramExecTypes; /* type OIDs for PARAM_EXEC Params */ + + Index lastPHId; /* highest PlaceHolderVar ID assigned */ + + Index lastRowMarkId; /* highest PlanRowMark ID assigned */ + + int lastPlanNodeId; /* highest plan node ID assigned */ + + bool transientPlan; /* redo plan when TransactionXmin changes? */ + + bool dependsOnRole; /* is plan specific to current role? */ + + bool parallelModeOK; /* parallel mode potentially OK? */ + + bool parallelModeNeeded; /* parallel mode actually required? */ + + char maxParallelHazard; /* worst PROPARALLEL hazard level */ + + PartitionDirectory partition_directory; /* partition descriptors */ +} 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. + *---------- + */ +#ifndef HAVE_PLANNERINFO_TYPEDEF +typedef struct PlannerInfo PlannerInfo; +#define HAVE_PLANNERINFO_TYPEDEF 1 +#endif + +struct PlannerInfo +{ + NodeTag type; + + Query *parse; /* the Query being planned */ + + PlannerGlobal *glob; /* global info for current planner run */ + + Index query_level; /* 1 at the outermost Query */ + + PlannerInfo *parent_root; /* NULL at outermost Query */ + + /* + * 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 *plan_params; /* list of PlannerParamItems, see below */ + 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; /* All 1-rel RelOptInfos */ + int simple_rel_array_size; /* allocated size of array */ + + /* + * 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. + */ + RangeTblEntry **simple_rte_array; /* rangetable as an array */ + + /* + * 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. + */ + struct AppendRelInfo **append_rel_array; + + /* + * all_baserels is a Relids set of all base relids (but not "other" + * relids) in the query; that is, the Relids identifier of the final join + * we need to form. This is computed in make_one_rel, just before we + * start making Paths. + */ + Relids all_baserels; + + /* + * nullable_baserels is a Relids set of base relids that are nullable by + * some outer join in the jointree; these are rels that are potentially + * nullable below the WHERE clause, SELECT targetlist, etc. This is + * computed in deconstruct_jointree. + */ + Relids nullable_baserels; + + /* + * 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; /* list of join-relation RelOptInfos */ + struct HTAB *join_rel_hash; /* optional hashtable for join relations */ + + /* + * 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. + */ + List **join_rel_level; /* lists of join-relation RelOptInfos */ + int join_cur_level; /* index of list being extended */ + + List *init_plans; /* init SubPlans for query */ + + List *cte_plan_ids; /* per-CTE-item list of subplan IDs */ + + List *multiexpr_params; /* List of Lists of Params for MULTIEXPR + * subquery outputs */ + + List *eq_classes; /* list of active EquivalenceClasses */ + + bool ec_merging_done; /* set true once ECs are canonical */ + + List *canon_pathkeys; /* list of "canonical" PathKeys */ + + List *left_join_clauses; /* list of RestrictInfos for mergejoinable + * outer join clauses w/nonnullable var on + * left */ + + List *right_join_clauses; /* list of RestrictInfos for mergejoinable + * outer join clauses w/nonnullable var on + * right */ + + List *full_join_clauses; /* list of RestrictInfos for mergejoinable + * full join clauses */ + + List *join_info_list; /* list of SpecialJoinInfos */ + + /* + * 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 AppendRelInfos */ + + List *rowMarks; /* list of PlanRowMarks */ + + List *placeholder_list; /* list of PlaceHolderInfos */ + + List *fkey_list; /* list of ForeignKeyOptInfos */ + + List *query_pathkeys; /* desired pathkeys for query_planner() */ + + List *group_pathkeys; /* groupClause pathkeys, if any */ + List *window_pathkeys; /* pathkeys of bottom window, if any */ + List *distinct_pathkeys; /* distinctClause pathkeys, if any */ + List *sort_pathkeys; /* sortClause pathkeys, if any */ + + List *part_schemes; /* Canonicalised partition schemes used in the + * query. */ + + List *initial_rels; /* RelOptInfos we are now trying to join */ + + /* Use fetch_upper_rel() to get any particular upper rel */ + List *upper_rels[UPPERREL_FINAL + 1]; /* upper-rel RelOptInfos */ + + /* Result tlists chosen by grouping_planner for upper-stage processing */ + struct PathTarget *upper_targets[UPPERREL_FINAL + 1]; + + /* + * The fully-processed targetlist is kept here. It differs from + * parse->targetList in that (for INSERT and UPDATE) 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 this 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; + + /* Fields filled during create_plan() for use in setrefs.c */ + AttrNumber *grouping_map; /* for GroupingFunc fixup */ + List *minmax_aggs; /* List of MinMaxAggInfos */ + + MemoryContext planner_cxt; /* context holding PlannerInfo */ + + double total_table_pages; /* # of pages in all non-dummy tables of + * query */ + + double tuple_fraction; /* tuple_fraction passed to query_planner */ + double limit_tuples; /* limit_tuples passed to query_planner */ + + Index qual_security_level; /* minimum security_level for quals */ + /* Note: qual_security_level is zero if there are no securityQuals */ + + InheritanceKind inhTargetKind; /* indicates if the target relation is an + * inheritance child or partition or a + * partitioned table */ + bool hasJoinRTEs; /* true if any RTEs are RTE_JOIN kind */ + bool hasLateralRTEs; /* true if any RTEs are marked LATERAL */ + bool hasHavingQual; /* true if havingQual was non-null */ + bool hasPseudoConstantQuals; /* true if any RestrictInfo has + * pseudoconstant = true */ + bool hasRecursion; /* true if planning a recursive WITH item */ + + /* These fields are used only when hasRecursion is true: */ + int wt_param_id; /* PARAM_EXEC ID for the work table */ + struct Path *non_recursive_path; /* a path for non-recursive term */ + + /* These fields are workspace for createplan.c */ + Relids curOuterRels; /* outer rels above current node */ + List *curOuterParams; /* not-yet-assigned NestLoopParams */ + + /* optional private data for join_search_hook, e.g., GEQO */ + void *join_search_private; + + /* 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. 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. + * + * Lastly, there is a RelOptKind for "dead" relations, which are base rels + * that we have proven we don't need to join after all. + * + * 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 base-relation identifiers; it is a base relation + * if there is just one, a join relation if more than one + * 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 + * 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) + * 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 + * partitioned_child_rels - RT indexes of unpruned partitions of + * this relation that are partitioned tables + * themselves, in hierarchical order + * + * 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. + *---------- + */ +typedef enum RelOptKind +{ + RELOPT_BASEREL, + RELOPT_JOINREL, + RELOPT_OTHER_MEMBER_REL, + RELOPT_OTHER_JOINREL, + RELOPT_UPPER_REL, + RELOPT_OTHER_UPPER_REL, + RELOPT_DEADREL +} 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 +{ + NodeTag type; + + RelOptKind reloptkind; + + /* all relations included in this RelOptInfo */ + Relids relids; /* set of base relids (rangetable indexes) */ + + /* size estimates generated by planner */ + double rows; /* estimated number of result tuples */ + + /* per-relation planner control flags */ + bool consider_startup; /* keep cheap-startup-cost paths? */ + bool consider_param_startup; /* ditto, for parameterized paths? */ + bool consider_parallel; /* consider parallel paths? */ + + /* default result targetlist for Paths scanning this relation */ + struct PathTarget *reltarget; /* list of Vars/Exprs, cost, width */ + + /* 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) */ + Relids direct_lateral_relids; /* rels directly laterally referenced */ + Relids lateral_relids; /* minimum parameterization of rel */ + + /* information about a base rel (not set for join rels!) */ + Index relid; + Oid reltablespace; /* containing tablespace */ + RTEKind rtekind; /* RELATION, SUBQUERY, FUNCTION, etc */ + AttrNumber min_attr; /* smallest attrno of rel (often <0) */ + AttrNumber max_attr; /* largest attrno of rel */ + Relids *attr_needed; /* array indexed [min_attr .. max_attr] */ + int32 *attr_widths; /* array indexed [min_attr .. max_attr] */ + List *lateral_vars; /* LATERAL Vars and PHVs referenced by rel */ + Relids lateral_referencers; /* rels that reference me laterally */ + List *indexlist; /* list of IndexOptInfo */ + List *statlist; /* list of StatisticExtInfo */ + BlockNumber pages; /* size estimates derived from pg_class */ + double tuples; + double allvisfrac; + Bitmapset *eclass_indexes; /* Indexes in PlannerInfo's eq_classes list of + * ECs that mention this rel */ + PlannerInfo *subroot; /* if subquery */ + List *subplan_params; /* if subquery */ + int rel_parallel_workers; /* wanted number of parallel workers */ + + /* Information about foreign tables and foreign joins */ + Oid serverid; /* identifies server for the table or join */ + Oid userid; /* identifies user to check access as */ + bool useridiscurrent; /* join is only valid for current user */ + /* use "struct FdwRoutine" to avoid including fdwapi.h here */ + struct FdwRoutine *fdwroutine; + void *fdw_private; + + /* cache space for remembering if we have proven this relation unique */ + List *unique_for_rels; /* known unique for these other relid + * set(s) */ + List *non_unique_for_rels; /* known not unique for these set(s) */ + + /* used by various scans and joins: */ + List *baserestrictinfo; /* RestrictInfo structures (if base rel) */ + QualCost baserestrictcost; /* cost of evaluating the above */ + Index baserestrict_min_security; /* min security_level found in + * baserestrictinfo */ + List *joininfo; /* RestrictInfo structures for join clauses + * involving this rel */ + bool has_eclass_joins; /* T means joininfo is incomplete */ + + /* used by partitionwise joins: */ + bool consider_partitionwise_join; /* consider partitionwise join + * paths? (if partitioned rel) */ + Relids top_parent_relids; /* Relids of topmost parents (if "other" + * rel) */ + + /* used for partitioned relations: */ + PartitionScheme part_scheme; /* Partitioning scheme */ + int nparts; /* Number of partitions; -1 if not yet set; in + * case of a join relation 0 means it's + * considered unpartitioned */ + struct PartitionBoundInfoData *boundinfo; /* Partition bounds */ + bool partbounds_merged; /* True if partition bounds were created + * by partition_bounds_merge() */ + List *partition_qual; /* Partition constraint, if not the root */ + struct RelOptInfo **part_rels; /* Array of RelOptInfos of partitions, + * stored in the same order as bounds */ + Relids all_partrels; /* Relids set of all partition relids */ + List **partexprs; /* Non-nullable partition key expressions */ + List **nullable_partexprs; /* Nullable partition key expressions */ + List *partitioned_child_rels; /* List of RT indexes */ +} 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 +{ + NodeTag type; + + Oid indexoid; /* OID of the index relation */ + Oid reltablespace; /* tablespace of index (not table) */ + RelOptInfo *rel; /* back-link to index's table */ + + /* index-size statistics (from pg_class and elsewhere) */ + BlockNumber pages; /* number of disk pages in index */ + double tuples; /* number of index tuples in index */ + int tree_height; /* index tree height, or -1 if unknown */ + + /* index descriptor information */ + int ncolumns; /* number of columns in index */ + int nkeycolumns; /* number of key columns in index */ + int *indexkeys; /* column numbers of index's attributes both + * key and included columns, or 0 */ + Oid *indexcollations; /* OIDs of collations of index columns */ + Oid *opfamily; /* OIDs of operator families for columns */ + Oid *opcintype; /* OIDs of opclass declared input data types */ + Oid *sortopfamily; /* OIDs of btree opfamilies, if orderable */ + bool *reverse_sort; /* is sort order descending? */ + bool *nulls_first; /* do NULLs come first in the sort order? */ + bytea **opclassoptions; /* opclass-specific options for columns */ + bool *canreturn; /* which index cols can be returned in an + * index-only scan? */ + Oid relam; /* OID of the access method (in pg_am) */ + + List *indexprs; /* expressions for non-simple index columns */ + List *indpred; /* predicate if a partial index, else NIL */ + + List *indextlist; /* targetlist representing index columns */ + + List *indrestrictinfo; /* 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()) */ + + bool predOK; /* true if index predicate matches query */ + bool unique; /* true if a unique index */ + bool immediate; /* is uniqueness enforced immediately? */ + bool hypothetical; /* true if index doesn't really exist */ + + /* Remaining fields are copied from the index AM's API struct: */ + bool amcanorderbyop; /* does AM support order by operator result? */ + bool amoptionalkey; /* can query omit key for the first column? */ + bool amsearcharray; /* can AM handle ScalarArrayOpExpr quals? */ + bool amsearchnulls; /* can AM search for NULL/NOT NULL entries? */ + bool amhasgettuple; /* does AM have amgettuple interface? */ + bool amhasgetbitmap; /* does AM have amgetbitmap interface? */ + bool amcanparallel; /* does AM support parallel scan? */ + bool amcanmarkpos; /* does AM support mark/restore? */ + /* Rather than include amapi.h here, we declare amcostestimate like this */ + void (*amcostestimate) (); /* AM's cost estimator */ +}; + +/* + * 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 +{ + NodeTag type; + + /* Basic data about the foreign key (fetched from catalogs): */ + Index con_relid; /* RT index of the referencing table */ + Index ref_relid; /* RT index of the referenced table */ + int nkeys; /* number of columns in the foreign key */ + AttrNumber conkey[INDEX_MAX_KEYS]; /* cols in referencing table */ + AttrNumber confkey[INDEX_MAX_KEYS]; /* cols in referenced table */ + Oid conpfeqop[INDEX_MAX_KEYS]; /* PK = FK operator OIDs */ + + /* Derived info about whether FK's equality conditions match the query: */ + int nmatched_ec; /* # of FK cols matched by ECs */ + int nmatched_rcols; /* # of FK cols matched by non-EC rinfos */ + int nmatched_ri; /* total # of non-EC rinfos matched to FK */ + /* Pointer to eclass matching each column's condition, if there is one */ + struct EquivalenceClass *eclass[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 +{ + NodeTag type; + + Oid statOid; /* OID of the statistics row */ + RelOptInfo *rel; /* back-link to statistic's table */ + char kind; /* statistics kind of this entry */ + Bitmapset *keys; /* attnums of the columns covered */ +} StatisticExtInfo; + +/* + * EquivalenceClasses + * + * Whenever we can determine that a mergejoinable equality clause A = B is + * not delayed by any outer join, 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.) + * + * 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. + * + * We allow equality clauses appearing below the nullable side of an outer join + * to form EquivalenceClasses, but these have a slightly different meaning: + * the included values might be all NULL rather than all the same non-null + * values. See src/backend/optimizer/README for more on that point. + * + * 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. + */ +typedef struct EquivalenceClass +{ + 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_below_outer_join; /* equivalence applies below an OJ */ + 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 const and isn't below-outer-join, 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 && !(eclass)->ec_below_outer_join) + +/* + * 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 +{ + NodeTag type; + + Expr *em_expr; /* the expression represented */ + Relids em_relids; /* all relids appearing in em_expr */ + Relids em_nullable_relids; /* nullable by lower outer joins */ + 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 */ +} 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 +{ + NodeTag type; + + EquivalenceClass *pk_eclass; /* the value that is ordered */ + 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; + + +/* + * 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 +{ + NodeTag type; + List *exprs; /* list of expressions to be computed */ + Index *sortgrouprefs; /* corresponding sort/group refnos, or 0 */ + QualCost cost; /* cost of evaluating the expressions */ + int width; /* estimated avg width of result tuples */ +} 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. + */ +typedef struct ParamPathInfo +{ + NodeTag type; + + Relids ppi_req_outer; /* rels supplying parameters used by path */ + double ppi_rows; /* estimated number of result tuples */ + List *ppi_clauses; /* join clauses available from outer rels */ +} 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. + */ +typedef struct Path +{ + NodeTag type; + + NodeTag pathtype; /* tag identifying scan/join method */ + + RelOptInfo *parent; /* the relation this path can build */ + PathTarget *pathtarget; /* list of Vars/Exprs, cost, width */ + + ParamPathInfo *param_info; /* parameterization info, or NULL if none */ + + bool parallel_aware; /* engage parallel-aware logic? */ + bool parallel_safe; /* OK to use as part of parallel plan? */ + int parallel_workers; /* desired # of workers; 0 = not parallel */ + + /* estimated size/costs for path (see costsize.c for more info) */ + double rows; /* estimated number of result tuples */ + Cost startup_cost; /* cost expended before fetching any tuples */ + Cost total_cost; /* total cost (assuming all tuples fetched) */ + + List *pathkeys; /* sort ordering of path's output */ + /* pathkeys is a List of PathKey nodes; see above */ +} 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 ordered index + * BackwardScanDirection: backward scan of an ordered index + * NoMovementScanDirection: scan of an unordered index, or don't care + * (The executor doesn't care whether it gets ForwardScanDirection or + * NoMovementScanDirection for an indexscan, but the planner wants to + * distinguish ordered from unordered indexes for building pathkeys.) + * + * '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 +{ + 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; + +/* + * 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 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. 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 relation by + * set_rel_pathlist_hook functions. + * + * 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; + /* RT indexes of non-leaf tables in a partition tree */ + List *partitioned_rels; + List *subpaths; /* list of component Paths */ + /* Index of first partial path in subpaths; list_length(subpaths) if none */ + int first_partial_path; + double 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; + /* RT indexes of non-leaf tables in a partition tree */ + List *partitioned_rels; + List *subpaths; /* list of component Paths */ + double 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; + +/* + * 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 +{ + 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 +{ + 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 JoinPath 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 */ + double 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 */ + double 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 +{ + NodeTag type; + List *set; /* grouping set as list of sortgrouprefs */ + double numGroups; /* est. number of result groups */ +} GroupingSetData; + +typedef struct RollupData +{ + NodeTag type; + List *groupClause; /* applicable subset of parse->groupClause */ + List *gsets; /* lists of integer indexes into groupClause */ + List *gsets_data; /* list of GroupingSetData */ + double 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 */ +} 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 */ + double 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 */ + double 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 modifications + * + * We represent most things that will be in the ModifyTable plan node + * literally, except we have child Path(s) not Plan(s). But analysis of the + * OnConflictExpr is deferred to createplan.c, as is collection of FDW data. + */ +typedef struct ModifyTablePath +{ + Path path; + CmdType operation; /* INSERT, UPDATE, or DELETE */ + bool canSetTag; /* do we set the command tag/es_processed? */ + Index nominalRelation; /* Parent RT index for use of EXPLAIN */ + Index rootRelation; /* Root RT index, if target is partitioned */ + bool partColsUpdated; /* some part key in hierarchy updated */ + List *resultRelations; /* integer list of RT indexes */ + List *subpaths; /* Path(s) producing source data */ + List *subroots; /* per-target-table PlannerInfos */ + 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 */ +} 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 rel, it will + * appear in the joininfo list of every RelOptInfo that describes a strict + * subset of the base rels 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 base rels it references, however. + * + * When we construct a join rel that includes all the base rels 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 base rels 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. + * + * When dealing with outer joins we have to be very careful about pushing qual + * clauses up and down the tree. An outer join's own JOIN/ON conditions must + * be evaluated exactly at that join node, unless they are "degenerate" + * conditions that reference only Vars from the nullable side of the join. + * Quals appearing in WHERE or in a JOIN above the outer join cannot be pushed + * down below the outer join, if they reference any nullable Vars. + * 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.) + * + * RestrictInfo nodes also contain an outerjoin_delayed flag, which is true + * if the clause's applicability must be delayed due to any outer joins + * appearing below it (ie, it has to be postponed to some join level higher + * than the set of relations it actually references). + * + * 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.) + * + * There is also a nullable_relids field, which is the set of rels the clause + * references that can be forced null by some outer join below the clause. + * + * outerjoin_delayed = true is subtly different from nullable_relids != NULL: + * a clause might reference some nullable rels and yet not be + * outerjoin_delayed because it also references all the other rels of the + * outer join(s). A clause that is not outerjoin_delayed can be enforced + * anywhere it is computable. + * + * 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 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. + */ + +typedef struct RestrictInfo +{ + NodeTag type; + + Expr *clause; /* the represented clause of WHERE or JOIN */ + + bool is_pushed_down; /* true if clause was pushed down in level */ + + bool outerjoin_delayed; /* true if delayed by lower outer join */ + + bool can_join; /* see comment above */ + + bool pseudoconstant; /* see comment above */ + + bool leakproof; /* true if known to contain no leaked Vars */ + + Index security_level; /* see comment above */ + + /* The set of relids (varnos) actually referenced in the clause: */ + Relids clause_relids; + + /* The set of relids required to evaluate the clause: */ + Relids required_relids; + + /* If an outer-join clause, the outer-side relations, else NULL: */ + Relids outer_relids; + + /* The relids used in the clause that are nullable by lower outer joins: */ + Relids nullable_relids; + + /* These fields are set for any binary opclause: */ + Relids left_relids; /* relids in left side of clause */ + Relids right_relids; /* relids in right side of clause */ + + /* This field is NULL unless clause is an OR clause: */ + Expr *orclause; /* modified clause with RestrictInfos */ + + /* This field is NULL unless clause is potentially redundant: */ + EquivalenceClass *parent_ec; /* generating EquivalenceClass */ + + /* cache space for cost and selectivity */ + QualCost eval_cost; /* eval cost of clause; -1 if not yet set */ + Selectivity norm_selec; /* selectivity for "normal" (JOIN_INNER) + * semantics; -1 if not yet set; >1 means a + * redundant clause */ + Selectivity outer_selec; /* selectivity for outer join semantics; -1 if + * not yet set */ + + /* valid if clause is mergejoinable, else NIL */ + List *mergeopfamilies; /* opfamilies containing clause operator */ + + /* cache space for mergeclause processing; NULL if not yet set */ + EquivalenceClass *left_ec; /* EquivalenceClass containing lefthand */ + EquivalenceClass *right_ec; /* EquivalenceClass containing righthand */ + EquivalenceMember *left_em; /* EquivalenceMember for lefthand */ + EquivalenceMember *right_em; /* EquivalenceMember for righthand */ + List *scansel_cache; /* list of MergeScanSelCache structs */ + + /* transient workspace for use while considering a specific join path */ + bool outer_is_left; /* T = outer var on left, F = on right */ + + /* valid if clause is hashjoinable, else InvalidOid: */ + Oid hashjoinoperator; /* copy of clause operator */ + + /* cache space for hashclause processing; -1 if not yet set */ + Selectivity left_bucketsize; /* avg bucketsize of left side */ + Selectivity right_bucketsize; /* avg bucketsize of right side */ + Selectivity left_mcvfreq; /* left side's most common val's freq */ + Selectivity right_mcvfreq; /* right side's most common val's freq */ +} 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. Typically the evaluation occurs below an outer + * join, and Var references above the outer join might thereby yield NULL + * instead of the expression value. + * + * 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. + */ + +typedef struct PlaceHolderVar +{ + Expr xpr; + Expr *phexpr; /* the represented expression */ + Relids phrels; /* base relids syntactically within expr src */ + Index phid; /* ID for PHV (unique within planner run) */ + Index phlevelsup; /* > 0 if PHV belongs to outer query */ +} 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 relids that must be + * available on each side when performing the special join. 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. + * + * 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 relids that are + * syntactically below this special join. (These are needed to help compute + * min_lefthand and min_righthand for higher joins.) + * + * delay_upper_joins is set true if we detect a pushed-down clause that has + * to be evaluated after this join is formed (because it references the RHS). + * Any outer joins that have such a clause and this join in their RHS cannot + * commute with this join, because that would leave noplace to check the + * pushed-down clause. (We don't track this for FULL JOINs, either.) + * + * 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.) + * + * jointype is never JOIN_RIGHT; a RIGHT JOIN is handled by switching + * the inputs to make it a LEFT JOIN. So the allowed values of jointype + * in a join_info_list member are only LEFT, FULL, SEMI, or ANTI. + * + * 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, delay_upper_joins, and + * of course 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 +{ + NodeTag type; + Relids min_lefthand; /* base relids in minimum LHS for join */ + Relids min_righthand; /* base relids in minimum RHS for join */ + Relids syn_lefthand; /* base relids syntactically within LHS */ + Relids syn_righthand; /* base relids syntactically within RHS */ + JoinType jointype; /* always INNER, LEFT, FULL, SEMI, or ANTI */ + bool lhs_strict; /* joinclause is strict for some LHS rel */ + bool delay_upper_joins; /* can't commute with upper RHS */ + /* 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 */ +}; + +/* + * 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 +{ + 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; /* array of parent attnos, or zeroes */ + + /* + * 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; + +/* + * 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 +{ + NodeTag type; + + Index phid; /* ID for PH (unique within planner run) */ + PlaceHolderVar *ph_var; /* copy of PlaceHolderVar tree */ + Relids ph_eval_at; /* lowest level we can evaluate value at */ + Relids ph_lateral; /* relids of contained lateral refs, if any */ + Relids ph_needed; /* highest level the value is needed at */ + int32 ph_width; /* estimated attribute 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 +{ + NodeTag type; + + Oid aggfnoid; /* pg_proc Oid of the aggregate */ + Oid aggsortop; /* Oid of its sort operator */ + Expr *target; /* expression we are aggregating on */ + PlannerInfo *subroot; /* modified "root" for planning the subquery */ + Path *path; /* access path for subquery */ + Cost pathcost; /* estimated cost to fetch first row */ + Param *param; /* param for subplan's output */ +} 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 +{ + 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; + double 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 */ + double outer_rows; + double inner_rows; + double outer_skip_rows; + double inner_skip_rows; + + /* private for cost_hashjoin code */ + int numbuckets; + int numbatches; + double inner_rows_total; +} JoinCostWorkspace; + +#endif /* PATHNODES_H */ |