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