diff options
Diffstat (limited to 'src/include/nodes/pathnodes.h')
| -rw-r--r-- | src/include/nodes/pathnodes.h | 3384 |
1 files changed, 3384 insertions, 0 deletions
diff --git a/src/include/nodes/pathnodes.h b/src/include/nodes/pathnodes.h new file mode 100644 index 0000000..94aebad --- /dev/null +++ b/src/include/nodes/pathnodes.h @@ -0,0 +1,3384 @@ +/*------------------------------------------------------------------------- + * + * pathnodes.h + * Definitions for planner's internal data structures, especially Paths. + * + * We don't support copying RelOptInfo, IndexOptInfo, or Path nodes. + * There are some subsidiary structs that are useful to copy, though. + * + * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * src/include/nodes/pathnodes.h + * + *------------------------------------------------------------------------- + */ +#ifndef PATHNODES_H +#define PATHNODES_H + +#include "access/sdir.h" +#include "lib/stringinfo.h" +#include "nodes/params.h" +#include "nodes/parsenodes.h" +#include "storage/block.h" + + +/* + * Relids + * Set of relation identifiers (indexes into the rangetable). + */ +typedef Bitmapset *Relids; + +/* + * When looking for a "cheapest path", this enum specifies whether we want + * cheapest startup cost or cheapest total cost. + */ +typedef enum CostSelector +{ + STARTUP_COST, TOTAL_COST +} CostSelector; + +/* + * The cost estimate produced by cost_qual_eval() includes both a one-time + * (startup) cost, and a per-tuple cost. + */ +typedef struct QualCost +{ + Cost startup; /* one-time cost */ + Cost per_tuple; /* per-evaluation cost */ +} QualCost; + +/* + * Costing aggregate function execution requires these statistics about + * the aggregates to be executed by a given Agg node. Note that the costs + * include the execution costs of the aggregates' argument expressions as + * well as the aggregate functions themselves. Also, the fields must be + * defined so that initializing the struct to zeroes with memset is correct. + */ +typedef struct AggClauseCosts +{ + QualCost transCost; /* total per-input-row execution costs */ + QualCost finalCost; /* total per-aggregated-row costs */ + Size transitionSpace; /* space for pass-by-ref transition data */ +} AggClauseCosts; + +/* + * This enum identifies the different types of "upper" (post-scan/join) + * relations that we might deal with during planning. + */ +typedef enum UpperRelationKind +{ + UPPERREL_SETOP, /* result of UNION/INTERSECT/EXCEPT, if any */ + UPPERREL_PARTIAL_GROUP_AGG, /* result of partial grouping/aggregation, if + * any */ + UPPERREL_GROUP_AGG, /* result of grouping/aggregation, if any */ + UPPERREL_WINDOW, /* result of window functions, if any */ + UPPERREL_PARTIAL_DISTINCT, /* result of partial "SELECT DISTINCT", if any */ + UPPERREL_DISTINCT, /* result of "SELECT DISTINCT", if any */ + UPPERREL_ORDERED, /* result of ORDER BY, if any */ + UPPERREL_FINAL /* result of any remaining top-level actions */ + /* NB: UPPERREL_FINAL must be last enum entry; it's used to size arrays */ +} UpperRelationKind; + +/*---------- + * PlannerGlobal + * Global information for planning/optimization + * + * PlannerGlobal holds state for an entire planner invocation; this state + * is shared across all levels of sub-Queries that exist in the command being + * planned. + * + * Not all fields are printed. (In some cases, there is no print support for + * the field type; in others, doing so would lead to infinite recursion.) + *---------- + */ +typedef struct PlannerGlobal +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + + /* Param values provided to planner() */ + ParamListInfo boundParams pg_node_attr(read_write_ignore); + + /* Plans for SubPlan nodes */ + List *subplans; + + /* PlannerInfos for SubPlan nodes */ + List *subroots pg_node_attr(read_write_ignore); + + /* indices of subplans that require REWIND */ + Bitmapset *rewindPlanIDs; + + /* "flat" rangetable for executor */ + List *finalrtable; + + /* "flat" list of RTEPermissionInfos */ + List *finalrteperminfos; + + /* "flat" list of PlanRowMarks */ + List *finalrowmarks; + + /* "flat" list of integer RT indexes */ + List *resultRelations; + + /* "flat" list of AppendRelInfos */ + List *appendRelations; + + /* OIDs of relations the plan depends on */ + List *relationOids; + + /* other dependencies, as PlanInvalItems */ + List *invalItems; + + /* type OIDs for PARAM_EXEC Params */ + List *paramExecTypes; + + /* highest PlaceHolderVar ID assigned */ + Index lastPHId; + + /* highest PlanRowMark ID assigned */ + Index lastRowMarkId; + + /* highest plan node ID assigned */ + int lastPlanNodeId; + + /* redo plan when TransactionXmin changes? */ + bool transientPlan; + + /* is plan specific to current role? */ + bool dependsOnRole; + + /* parallel mode potentially OK? */ + bool parallelModeOK; + + /* parallel mode actually required? */ + bool parallelModeNeeded; + + /* worst PROPARALLEL hazard level */ + char maxParallelHazard; + + /* partition descriptors */ + PartitionDirectory partition_directory pg_node_attr(read_write_ignore); +} PlannerGlobal; + +/* macro for fetching the Plan associated with a SubPlan node */ +#define planner_subplan_get_plan(root, subplan) \ + ((Plan *) list_nth((root)->glob->subplans, (subplan)->plan_id - 1)) + + +/*---------- + * PlannerInfo + * Per-query information for planning/optimization + * + * This struct is conventionally called "root" in all the planner routines. + * It holds links to all of the planner's working state, in addition to the + * original Query. Note that at present the planner extensively modifies + * the passed-in Query data structure; someday that should stop. + * + * For reasons explained in optimizer/optimizer.h, we define the typedef + * either here or in that header, whichever is read first. + * + * Not all fields are printed. (In some cases, there is no print support for + * the field type; in others, doing so would lead to infinite recursion or + * bloat dump output more than seems useful.) + *---------- + */ +#ifndef HAVE_PLANNERINFO_TYPEDEF +typedef struct PlannerInfo PlannerInfo; +#define HAVE_PLANNERINFO_TYPEDEF 1 +#endif + +struct PlannerInfo +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + + /* the Query being planned */ + Query *parse; + + /* global info for current planner run */ + PlannerGlobal *glob; + + /* 1 at the outermost Query */ + Index query_level; + + /* NULL at outermost Query */ + PlannerInfo *parent_root pg_node_attr(read_write_ignore); + + /* + * plan_params contains the expressions that this query level needs to + * make available to a lower query level that is currently being planned. + * outer_params contains the paramIds of PARAM_EXEC Params that outer + * query levels will make available to this query level. + */ + /* list of PlannerParamItems, see below */ + List *plan_params; + Bitmapset *outer_params; + + /* + * simple_rel_array holds pointers to "base rels" and "other rels" (see + * comments for RelOptInfo for more info). It is indexed by rangetable + * index (so entry 0 is always wasted). Entries can be NULL when an RTE + * does not correspond to a base relation, such as a join RTE or an + * unreferenced view RTE; or if the RelOptInfo hasn't been made yet. + */ + struct RelOptInfo **simple_rel_array pg_node_attr(array_size(simple_rel_array_size)); + /* allocated size of array */ + int simple_rel_array_size; + + /* + * simple_rte_array is the same length as simple_rel_array and holds + * pointers to the associated rangetable entries. Using this is a shade + * faster than using rt_fetch(), mostly due to fewer indirections. (Not + * printed because it'd be redundant with parse->rtable.) + */ + RangeTblEntry **simple_rte_array pg_node_attr(read_write_ignore); + + /* + * append_rel_array is the same length as the above arrays, and holds + * pointers to the corresponding AppendRelInfo entry indexed by + * child_relid, or NULL if the rel is not an appendrel child. The array + * itself is not allocated if append_rel_list is empty. (Not printed + * because it'd be redundant with append_rel_list.) + */ + struct AppendRelInfo **append_rel_array pg_node_attr(read_write_ignore); + + /* + * all_baserels is a Relids set of all base relids (but not joins or + * "other" rels) in the query. This is computed in deconstruct_jointree. + */ + Relids all_baserels; + + /* + * outer_join_rels is a Relids set of all outer-join relids in the query. + * This is computed in deconstruct_jointree. + */ + Relids outer_join_rels; + + /* + * all_query_rels is a Relids set of all base relids and outer join relids + * (but not "other" relids) in the query. This is the Relids identifier + * of the final join we need to form. This is computed in + * deconstruct_jointree. + */ + Relids all_query_rels; + + /* + * join_rel_list is a list of all join-relation RelOptInfos we have + * considered in this planning run. For small problems we just scan the + * list to do lookups, but when there are many join relations we build a + * hash table for faster lookups. The hash table is present and valid + * when join_rel_hash is not NULL. Note that we still maintain the list + * even when using the hash table for lookups; this simplifies life for + * GEQO. + */ + List *join_rel_list; + struct HTAB *join_rel_hash pg_node_attr(read_write_ignore); + + /* + * When doing a dynamic-programming-style join search, join_rel_level[k] + * is a list of all join-relation RelOptInfos of level k, and + * join_cur_level is the current level. New join-relation RelOptInfos are + * automatically added to the join_rel_level[join_cur_level] list. + * join_rel_level is NULL if not in use. + * + * Note: we've already printed all baserel and joinrel RelOptInfos above, + * so we don't dump join_rel_level or other lists of RelOptInfos. + */ + /* lists of join-relation RelOptInfos */ + List **join_rel_level pg_node_attr(read_write_ignore); + /* index of list being extended */ + int join_cur_level; + + /* init SubPlans for query */ + List *init_plans; + + /* + * per-CTE-item list of subplan IDs (or -1 if no subplan was made for that + * CTE) + */ + List *cte_plan_ids; + + /* List of Lists of Params for MULTIEXPR subquery outputs */ + List *multiexpr_params; + + /* list of JoinDomains used in the query (higher ones first) */ + List *join_domains; + + /* list of active EquivalenceClasses */ + List *eq_classes; + + /* set true once ECs are canonical */ + bool ec_merging_done; + + /* list of "canonical" PathKeys */ + List *canon_pathkeys; + + /* + * list of OuterJoinClauseInfos for mergejoinable outer join clauses + * w/nonnullable var on left + */ + List *left_join_clauses; + + /* + * list of OuterJoinClauseInfos for mergejoinable outer join clauses + * w/nonnullable var on right + */ + List *right_join_clauses; + + /* + * list of OuterJoinClauseInfos for mergejoinable full join clauses + */ + List *full_join_clauses; + + /* list of SpecialJoinInfos */ + List *join_info_list; + + /* counter for assigning RestrictInfo serial numbers */ + int last_rinfo_serial; + + /* + * all_result_relids is empty for SELECT, otherwise it contains at least + * parse->resultRelation. For UPDATE/DELETE/MERGE across an inheritance + * or partitioning tree, the result rel's child relids are added. When + * using multi-level partitioning, intermediate partitioned rels are + * included. leaf_result_relids is similar except that only actual result + * tables, not partitioned tables, are included in it. + */ + /* set of all result relids */ + Relids all_result_relids; + /* set of all leaf relids */ + Relids leaf_result_relids; + + /* + * list of AppendRelInfos + * + * Note: for AppendRelInfos describing partitions of a partitioned table, + * we guarantee that partitions that come earlier in the partitioned + * table's PartitionDesc will appear earlier in append_rel_list. + */ + List *append_rel_list; + + /* list of RowIdentityVarInfos */ + List *row_identity_vars; + + /* list of PlanRowMarks */ + List *rowMarks; + + /* list of PlaceHolderInfos */ + List *placeholder_list; + + /* array of PlaceHolderInfos indexed by phid */ + struct PlaceHolderInfo **placeholder_array pg_node_attr(read_write_ignore, array_size(placeholder_array_size)); + /* allocated size of array */ + int placeholder_array_size pg_node_attr(read_write_ignore); + + /* list of ForeignKeyOptInfos */ + List *fkey_list; + + /* desired pathkeys for query_planner() */ + List *query_pathkeys; + + /* groupClause pathkeys, if any */ + List *group_pathkeys; + + /* + * The number of elements in the group_pathkeys list which belong to the + * GROUP BY clause. Additional ones belong to ORDER BY / DISTINCT + * aggregates. + */ + int num_groupby_pathkeys; + + /* pathkeys of bottom window, if any */ + List *window_pathkeys; + /* distinctClause pathkeys, if any */ + List *distinct_pathkeys; + /* sortClause pathkeys, if any */ + List *sort_pathkeys; + + /* Canonicalised partition schemes used in the query. */ + List *part_schemes pg_node_attr(read_write_ignore); + + /* RelOptInfos we are now trying to join */ + List *initial_rels pg_node_attr(read_write_ignore); + + /* + * Upper-rel RelOptInfos. Use fetch_upper_rel() to get any particular + * upper rel. + */ + List *upper_rels[UPPERREL_FINAL + 1] pg_node_attr(read_write_ignore); + + /* Result tlists chosen by grouping_planner for upper-stage processing */ + struct PathTarget *upper_targets[UPPERREL_FINAL + 1] pg_node_attr(read_write_ignore); + + /* + * The fully-processed groupClause is kept here. It differs from + * parse->groupClause in that we remove any items that we can prove + * redundant, so that only the columns named here actually need to be + * compared to determine grouping. Note that it's possible for *all* the + * items to be proven redundant, implying that there is only one group + * containing all the query's rows. Hence, if you want to check whether + * GROUP BY was specified, test for nonempty parse->groupClause, not for + * nonempty processed_groupClause. + * + * Currently, when grouping sets are specified we do not attempt to + * optimize the groupClause, so that processed_groupClause will be + * identical to parse->groupClause. + */ + List *processed_groupClause; + + /* + * The fully-processed distinctClause is kept here. It differs from + * parse->distinctClause in that we remove any items that we can prove + * redundant, so that only the columns named here actually need to be + * compared to determine uniqueness. Note that it's possible for *all* + * the items to be proven redundant, implying that there should be only + * one output row. Hence, if you want to check whether DISTINCT was + * specified, test for nonempty parse->distinctClause, not for nonempty + * processed_distinctClause. + */ + List *processed_distinctClause; + + /* + * The fully-processed targetlist is kept here. It differs from + * parse->targetList in that (for INSERT) it's been reordered to match the + * target table, and defaults have been filled in. Also, additional + * resjunk targets may be present. preprocess_targetlist() does most of + * that work, but note that more resjunk targets can get added during + * appendrel expansion. (Hence, upper_targets mustn't get set up till + * after that.) + */ + List *processed_tlist; + + /* + * For UPDATE, this list contains the target table's attribute numbers to + * which the first N entries of processed_tlist are to be assigned. (Any + * additional entries in processed_tlist must be resjunk.) DO NOT use the + * resnos in processed_tlist to identify the UPDATE target columns. + */ + List *update_colnos; + + /* + * Fields filled during create_plan() for use in setrefs.c + */ + /* for GroupingFunc fixup (can't print: array length not known here) */ + AttrNumber *grouping_map pg_node_attr(read_write_ignore); + /* List of MinMaxAggInfos */ + List *minmax_aggs; + + /* context holding PlannerInfo */ + MemoryContext planner_cxt pg_node_attr(read_write_ignore); + + /* # of pages in all non-dummy tables of query */ + Cardinality total_table_pages; + + /* tuple_fraction passed to query_planner */ + Selectivity tuple_fraction; + /* limit_tuples passed to query_planner */ + Cardinality limit_tuples; + + /* + * Minimum security_level for quals. Note: qual_security_level is zero if + * there are no securityQuals. + */ + Index qual_security_level; + + /* true if any RTEs are RTE_JOIN kind */ + bool hasJoinRTEs; + /* true if any RTEs are marked LATERAL */ + bool hasLateralRTEs; + /* true if havingQual was non-null */ + bool hasHavingQual; + /* true if any RestrictInfo has pseudoconstant = true */ + bool hasPseudoConstantQuals; + /* true if we've made any of those */ + bool hasAlternativeSubPlans; + /* true once we're no longer allowed to add PlaceHolderInfos */ + bool placeholdersFrozen; + /* true if planning a recursive WITH item */ + bool hasRecursion; + + /* + * Information about aggregates. Filled by preprocess_aggrefs(). + */ + /* AggInfo structs */ + List *agginfos; + /* AggTransInfo structs */ + List *aggtransinfos; + /* number of aggs with DISTINCT/ORDER BY/WITHIN GROUP */ + int numOrderedAggs; + /* does any agg not support partial mode? */ + bool hasNonPartialAggs; + /* is any partial agg non-serializable? */ + bool hasNonSerialAggs; + + /* + * These fields are used only when hasRecursion is true: + */ + /* PARAM_EXEC ID for the work table */ + int wt_param_id; + /* a path for non-recursive term */ + struct Path *non_recursive_path; + + /* + * These fields are workspace for createplan.c + */ + /* outer rels above current node */ + Relids curOuterRels; + /* not-yet-assigned NestLoopParams */ + List *curOuterParams; + + /* + * These fields are workspace for setrefs.c. Each is an array + * corresponding to glob->subplans. (We could probably teach + * gen_node_support.pl how to determine the array length, but it doesn't + * seem worth the trouble, so just mark them read_write_ignore.) + */ + bool *isAltSubplan pg_node_attr(read_write_ignore); + bool *isUsedSubplan pg_node_attr(read_write_ignore); + + /* optional private data for join_search_hook, e.g., GEQO */ + void *join_search_private pg_node_attr(read_write_ignore); + + /* Does this query modify any partition key columns? */ + bool partColsUpdated; +}; + + +/* + * In places where it's known that simple_rte_array[] must have been prepared + * already, we just index into it to fetch RTEs. In code that might be + * executed before or after entering query_planner(), use this macro. + */ +#define planner_rt_fetch(rti, root) \ + ((root)->simple_rte_array ? (root)->simple_rte_array[rti] : \ + rt_fetch(rti, (root)->parse->rtable)) + +/* + * If multiple relations are partitioned the same way, all such partitions + * will have a pointer to the same PartitionScheme. A list of PartitionScheme + * objects is attached to the PlannerInfo. By design, the partition scheme + * incorporates only the general properties of the partition method (LIST vs. + * RANGE, number of partitioning columns and the type information for each) + * and not the specific bounds. + * + * We store the opclass-declared input data types instead of the partition key + * datatypes since the former rather than the latter are used to compare + * partition bounds. Since partition key data types and the opclass declared + * input data types are expected to be binary compatible (per ResolveOpClass), + * both of those should have same byval and length properties. + */ +typedef struct PartitionSchemeData +{ + char strategy; /* partition strategy */ + int16 partnatts; /* number of partition attributes */ + Oid *partopfamily; /* OIDs of operator families */ + Oid *partopcintype; /* OIDs of opclass declared input data types */ + Oid *partcollation; /* OIDs of partitioning collations */ + + /* Cached information about partition key data types. */ + int16 *parttyplen; + bool *parttypbyval; + + /* Cached information about partition comparison functions. */ + struct FmgrInfo *partsupfunc; +} PartitionSchemeData; + +typedef struct PartitionSchemeData *PartitionScheme; + +/*---------- + * RelOptInfo + * Per-relation information for planning/optimization + * + * For planning purposes, a "base rel" is either a plain relation (a table) + * or the output of a sub-SELECT or function that appears in the range table. + * In either case it is uniquely identified by an RT index. A "joinrel" + * is the joining of two or more base rels. A joinrel is identified by + * the set of RT indexes for its component baserels, along with RT indexes + * for any outer joins it has computed. We create RelOptInfo nodes for each + * baserel and joinrel, and store them in the PlannerInfo's simple_rel_array + * and join_rel_list respectively. + * + * Note that there is only one joinrel for any given set of component + * baserels, no matter what order we assemble them in; so an unordered + * set is the right datatype to identify it with. + * + * We also have "other rels", which are like base rels in that they refer to + * single RT indexes; but they are not part of the join tree, and are given + * a different RelOptKind to identify them. + * Currently the only kind of otherrels are those made for member relations + * of an "append relation", that is an inheritance set or UNION ALL subquery. + * An append relation has a parent RTE that is a base rel, which represents + * the entire append relation. The member RTEs are otherrels. The parent + * is present in the query join tree but the members are not. The member + * RTEs and otherrels are used to plan the scans of the individual tables or + * subqueries of the append set; then the parent baserel is given Append + * and/or MergeAppend paths comprising the best paths for the individual + * member rels. (See comments for AppendRelInfo for more information.) + * + * At one time we also made otherrels to represent join RTEs, for use in + * handling join alias Vars. Currently this is not needed because all join + * alias Vars are expanded to non-aliased form during preprocess_expression. + * + * We also have relations representing joins between child relations of + * different partitioned tables. These relations are not added to + * join_rel_level lists as they are not joined directly by the dynamic + * programming algorithm. + * + * There is also a RelOptKind for "upper" relations, which are RelOptInfos + * that describe post-scan/join processing steps, such as aggregation. + * Many of the fields in these RelOptInfos are meaningless, but their Path + * fields always hold Paths showing ways to do that processing step. + * + * Parts of this data structure are specific to various scan and join + * mechanisms. It didn't seem worth creating new node types for them. + * + * relids - Set of relation identifiers (RT indexes). This is a base + * relation if there is just one, a join relation if more; + * in the join case, RT indexes of any outer joins formed + * at or below this join are included along with baserels + * rows - estimated number of tuples in the relation after restriction + * clauses have been applied (ie, output rows of a plan for it) + * consider_startup - true if there is any value in keeping plain paths for + * this rel on the basis of having cheap startup cost + * consider_param_startup - the same for parameterized paths + * reltarget - Default Path output tlist for this rel; normally contains + * Var and PlaceHolderVar nodes for the values we need to + * output from this relation. + * List is in no particular order, but all rels of an + * appendrel set must use corresponding orders. + * NOTE: in an appendrel child relation, may contain + * arbitrary expressions pulled up from a subquery! + * pathlist - List of Path nodes, one for each potentially useful + * method of generating the relation + * ppilist - ParamPathInfo nodes for parameterized Paths, if any + * cheapest_startup_path - the pathlist member with lowest startup cost + * (regardless of ordering) among the unparameterized paths; + * or NULL if there is no unparameterized path + * cheapest_total_path - the pathlist member with lowest total cost + * (regardless of ordering) among the unparameterized paths; + * or if there is no unparameterized path, the path with lowest + * total cost among the paths with minimum parameterization + * cheapest_unique_path - for caching cheapest path to produce unique + * (no duplicates) output from relation; NULL if not yet requested + * cheapest_parameterized_paths - best paths for their parameterizations; + * always includes cheapest_total_path, even if that's unparameterized + * direct_lateral_relids - rels this rel has direct LATERAL references to + * lateral_relids - required outer rels for LATERAL, as a Relids set + * (includes both direct and indirect lateral references) + * + * If the relation is a base relation it will have these fields set: + * + * relid - RTE index (this is redundant with the relids field, but + * is provided for convenience of access) + * rtekind - copy of RTE's rtekind field + * min_attr, max_attr - range of valid AttrNumbers for rel + * attr_needed - array of bitmapsets indicating the highest joinrel + * in which each attribute is needed; if bit 0 is set then + * the attribute is needed as part of final targetlist + * attr_widths - cache space for per-attribute width estimates; + * zero means not computed yet + * nulling_relids - relids of outer joins that can null this rel + * lateral_vars - lateral cross-references of rel, if any (list of + * Vars and PlaceHolderVars) + * lateral_referencers - relids of rels that reference this one laterally + * (includes both direct and indirect lateral references) + * indexlist - list of IndexOptInfo nodes for relation's indexes + * (always NIL if it's not a table or partitioned table) + * pages - number of disk pages in relation (zero if not a table) + * tuples - number of tuples in relation (not considering restrictions) + * allvisfrac - fraction of disk pages that are marked all-visible + * eclass_indexes - EquivalenceClasses that mention this rel (filled + * only after EC merging is complete) + * subroot - PlannerInfo for subquery (NULL if it's not a subquery) + * subplan_params - list of PlannerParamItems to be passed to subquery + * + * Note: for a subquery, tuples and subroot are not set immediately + * upon creation of the RelOptInfo object; they are filled in when + * set_subquery_pathlist processes the object. + * + * For otherrels that are appendrel members, these fields are filled + * in just as for a baserel, except we don't bother with lateral_vars. + * + * If the relation is either a foreign table or a join of foreign tables that + * all belong to the same foreign server and are assigned to the same user to + * check access permissions as (cf checkAsUser), these fields will be set: + * + * serverid - OID of foreign server, if foreign table (else InvalidOid) + * userid - OID of user to check access as (InvalidOid means current user) + * useridiscurrent - we've assumed that userid equals current user + * fdwroutine - function hooks for FDW, if foreign table (else NULL) + * fdw_private - private state for FDW, if foreign table (else NULL) + * + * Two fields are used to cache knowledge acquired during the join search + * about whether this rel is provably unique when being joined to given other + * relation(s), ie, it can have at most one row matching any given row from + * that join relation. Currently we only attempt such proofs, and thus only + * populate these fields, for base rels; but someday they might be used for + * join rels too: + * + * unique_for_rels - list of Relid sets, each one being a set of other + * rels for which this one has been proven unique + * non_unique_for_rels - list of Relid sets, each one being a set of + * other rels for which we have tried and failed to prove + * this one unique + * + * The presence of the following fields depends on the restrictions + * and joins that the relation participates in: + * + * baserestrictinfo - List of RestrictInfo nodes, containing info about + * each non-join qualification clause in which this relation + * participates (only used for base rels) + * baserestrictcost - Estimated cost of evaluating the baserestrictinfo + * clauses at a single tuple (only used for base rels) + * baserestrict_min_security - Smallest security_level found among + * clauses in baserestrictinfo + * joininfo - List of RestrictInfo nodes, containing info about each + * join clause in which this relation participates (but + * note this excludes clauses that might be derivable from + * EquivalenceClasses) + * has_eclass_joins - flag that EquivalenceClass joins are possible + * + * Note: Keeping a restrictinfo list in the RelOptInfo is useful only for + * base rels, because for a join rel the set of clauses that are treated as + * restrict clauses varies depending on which sub-relations we choose to join. + * (For example, in a 3-base-rel join, a clause relating rels 1 and 2 must be + * treated as a restrictclause if we join {1} and {2 3} to make {1 2 3}; but + * if we join {1 2} and {3} then that clause will be a restrictclause in {1 2} + * and should not be processed again at the level of {1 2 3}.) Therefore, + * the restrictinfo list in the join case appears in individual JoinPaths + * (field joinrestrictinfo), not in the parent relation. But it's OK for + * the RelOptInfo to store the joininfo list, because that is the same + * for a given rel no matter how we form it. + * + * We store baserestrictcost in the RelOptInfo (for base relations) because + * we know we will need it at least once (to price the sequential scan) + * and may need it multiple times to price index scans. + * + * A join relation is considered to be partitioned if it is formed from a + * join of two relations that are partitioned, have matching partitioning + * schemes, and are joined on an equijoin of the partitioning columns. + * Under those conditions we can consider the join relation to be partitioned + * by either relation's partitioning keys, though some care is needed if + * either relation can be forced to null by outer-joining. For example, an + * outer join like (A LEFT JOIN B ON A.a = B.b) may produce rows with B.b + * NULL. These rows may not fit the partitioning conditions imposed on B. + * Hence, strictly speaking, the join is not partitioned by B.b and thus + * partition keys of an outer join should include partition key expressions + * from the non-nullable side only. However, if a subsequent join uses + * strict comparison operators (and all commonly-used equijoin operators are + * strict), the presence of nulls doesn't cause a problem: such rows couldn't + * match anything on the other side and thus they don't create a need to do + * any cross-partition sub-joins. Hence we can treat such values as still + * partitioning the join output for the purpose of additional partitionwise + * joining, so long as a strict join operator is used by the next join. + * + * If the relation is partitioned, these fields will be set: + * + * part_scheme - Partitioning scheme of the relation + * nparts - Number of partitions + * boundinfo - Partition bounds + * partbounds_merged - true if partition bounds are merged ones + * partition_qual - Partition constraint if not the root + * part_rels - RelOptInfos for each partition + * all_partrels - Relids set of all partition relids + * partexprs, nullable_partexprs - Partition key expressions + * + * The partexprs and nullable_partexprs arrays each contain + * part_scheme->partnatts elements. Each of the elements is a list of + * partition key expressions. For partitioned base relations, there is one + * expression in each partexprs element, and nullable_partexprs is empty. + * For partitioned join relations, each base relation within the join + * contributes one partition key expression per partitioning column; + * that expression goes in the partexprs[i] list if the base relation + * is not nullable by this join or any lower outer join, or in the + * nullable_partexprs[i] list if the base relation is nullable. + * Furthermore, FULL JOINs add extra nullable_partexprs expressions + * corresponding to COALESCE expressions of the left and right join columns, + * to simplify matching join clauses to those lists. + * + * Not all fields are printed. (In some cases, there is no print support for + * the field type.) + *---------- + */ + +/* Bitmask of flags supported by table AMs */ +#define AMFLAG_HAS_TID_RANGE (1 << 0) + +typedef enum RelOptKind +{ + RELOPT_BASEREL, + RELOPT_JOINREL, + RELOPT_OTHER_MEMBER_REL, + RELOPT_OTHER_JOINREL, + RELOPT_UPPER_REL, + RELOPT_OTHER_UPPER_REL +} RelOptKind; + +/* + * Is the given relation a simple relation i.e a base or "other" member + * relation? + */ +#define IS_SIMPLE_REL(rel) \ + ((rel)->reloptkind == RELOPT_BASEREL || \ + (rel)->reloptkind == RELOPT_OTHER_MEMBER_REL) + +/* Is the given relation a join relation? */ +#define IS_JOIN_REL(rel) \ + ((rel)->reloptkind == RELOPT_JOINREL || \ + (rel)->reloptkind == RELOPT_OTHER_JOINREL) + +/* Is the given relation an upper relation? */ +#define IS_UPPER_REL(rel) \ + ((rel)->reloptkind == RELOPT_UPPER_REL || \ + (rel)->reloptkind == RELOPT_OTHER_UPPER_REL) + +/* Is the given relation an "other" relation? */ +#define IS_OTHER_REL(rel) \ + ((rel)->reloptkind == RELOPT_OTHER_MEMBER_REL || \ + (rel)->reloptkind == RELOPT_OTHER_JOINREL || \ + (rel)->reloptkind == RELOPT_OTHER_UPPER_REL) + +typedef struct RelOptInfo +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + + RelOptKind reloptkind; + + /* + * all relations included in this RelOptInfo; set of base + OJ relids + * (rangetable indexes) + */ + Relids relids; + + /* + * size estimates generated by planner + */ + /* estimated number of result tuples */ + Cardinality rows; + + /* + * per-relation planner control flags + */ + /* keep cheap-startup-cost paths? */ + bool consider_startup; + /* ditto, for parameterized paths? */ + bool consider_param_startup; + /* consider parallel paths? */ + bool consider_parallel; + + /* + * default result targetlist for Paths scanning this relation; list of + * Vars/Exprs, cost, width + */ + struct PathTarget *reltarget; + + /* + * materialization information + */ + List *pathlist; /* Path structures */ + List *ppilist; /* ParamPathInfos used in pathlist */ + List *partial_pathlist; /* partial Paths */ + struct Path *cheapest_startup_path; + struct Path *cheapest_total_path; + struct Path *cheapest_unique_path; + List *cheapest_parameterized_paths; + + /* + * parameterization information needed for both base rels and join rels + * (see also lateral_vars and lateral_referencers) + */ + /* rels directly laterally referenced */ + Relids direct_lateral_relids; + /* minimum parameterization of rel */ + Relids lateral_relids; + + /* + * information about a base rel (not set for join rels!) + */ + Index relid; + /* containing tablespace */ + Oid reltablespace; + /* RELATION, SUBQUERY, FUNCTION, etc */ + RTEKind rtekind; + /* smallest attrno of rel (often <0) */ + AttrNumber min_attr; + /* largest attrno of rel */ + AttrNumber max_attr; + /* array indexed [min_attr .. max_attr] */ + Relids *attr_needed pg_node_attr(read_write_ignore); + /* array indexed [min_attr .. max_attr] */ + int32 *attr_widths pg_node_attr(read_write_ignore); + /* relids of outer joins that can null this baserel */ + Relids nulling_relids; + /* LATERAL Vars and PHVs referenced by rel */ + List *lateral_vars; + /* rels that reference this baserel laterally */ + Relids lateral_referencers; + /* list of IndexOptInfo */ + List *indexlist; + /* list of StatisticExtInfo */ + List *statlist; + /* size estimates derived from pg_class */ + BlockNumber pages; + Cardinality tuples; + double allvisfrac; + /* indexes in PlannerInfo's eq_classes list of ECs that mention this rel */ + Bitmapset *eclass_indexes; + PlannerInfo *subroot; /* if subquery */ + List *subplan_params; /* if subquery */ + /* wanted number of parallel workers */ + int rel_parallel_workers; + /* Bitmask of optional features supported by the table AM */ + uint32 amflags; + + /* + * Information about foreign tables and foreign joins + */ + /* identifies server for the table or join */ + Oid serverid; + /* identifies user to check access as; 0 means to check as current user */ + Oid userid; + /* join is only valid for current user */ + bool useridiscurrent; + /* use "struct FdwRoutine" to avoid including fdwapi.h here */ + struct FdwRoutine *fdwroutine pg_node_attr(read_write_ignore); + void *fdw_private pg_node_attr(read_write_ignore); + + /* + * cache space for remembering if we have proven this relation unique + */ + /* known unique for these other relid set(s) */ + List *unique_for_rels; + /* known not unique for these set(s) */ + List *non_unique_for_rels; + + /* + * used by various scans and joins: + */ + /* RestrictInfo structures (if base rel) */ + List *baserestrictinfo; + /* cost of evaluating the above */ + QualCost baserestrictcost; + /* min security_level found in baserestrictinfo */ + Index baserestrict_min_security; + /* RestrictInfo structures for join clauses involving this rel */ + List *joininfo; + /* T means joininfo is incomplete */ + bool has_eclass_joins; + + /* + * used by partitionwise joins: + */ + /* consider partitionwise join paths? (if partitioned rel) */ + bool consider_partitionwise_join; + + /* + * inheritance links, if this is an otherrel (otherwise NULL): + */ + /* Immediate parent relation (dumping it would be too verbose) */ + struct RelOptInfo *parent pg_node_attr(read_write_ignore); + /* Topmost parent relation (dumping it would be too verbose) */ + struct RelOptInfo *top_parent pg_node_attr(read_write_ignore); + /* Relids of topmost parent (redundant, but handy) */ + Relids top_parent_relids; + + /* + * used for partitioned relations: + */ + /* Partitioning scheme */ + PartitionScheme part_scheme pg_node_attr(read_write_ignore); + + /* + * Number of partitions; -1 if not yet set; in case of a join relation 0 + * means it's considered unpartitioned + */ + int nparts; + /* Partition bounds */ + struct PartitionBoundInfoData *boundinfo pg_node_attr(read_write_ignore); + /* True if partition bounds were created by partition_bounds_merge() */ + bool partbounds_merged; + /* Partition constraint, if not the root */ + List *partition_qual; + + /* + * Array of RelOptInfos of partitions, stored in the same order as bounds + * (don't print, too bulky and duplicative) + */ + struct RelOptInfo **part_rels pg_node_attr(read_write_ignore); + + /* + * Bitmap with members acting as indexes into the part_rels[] array to + * indicate which partitions survived partition pruning. + */ + Bitmapset *live_parts; + /* Relids set of all partition relids */ + Relids all_partrels; + + /* + * These arrays are of length partkey->partnatts, which we don't have at + * hand, so don't try to print + */ + + /* Non-nullable partition key expressions */ + List **partexprs pg_node_attr(read_write_ignore); + /* Nullable partition key expressions */ + List **nullable_partexprs pg_node_attr(read_write_ignore); +} RelOptInfo; + +/* + * Is given relation partitioned? + * + * It's not enough to test whether rel->part_scheme is set, because it might + * be that the basic partitioning properties of the input relations matched + * but the partition bounds did not. Also, if we are able to prove a rel + * dummy (empty), we should henceforth treat it as unpartitioned. + */ +#define IS_PARTITIONED_REL(rel) \ + ((rel)->part_scheme && (rel)->boundinfo && (rel)->nparts > 0 && \ + (rel)->part_rels && !IS_DUMMY_REL(rel)) + +/* + * Convenience macro to make sure that a partitioned relation has all the + * required members set. + */ +#define REL_HAS_ALL_PART_PROPS(rel) \ + ((rel)->part_scheme && (rel)->boundinfo && (rel)->nparts > 0 && \ + (rel)->part_rels && (rel)->partexprs && (rel)->nullable_partexprs) + +/* + * IndexOptInfo + * Per-index information for planning/optimization + * + * indexkeys[], indexcollations[] each have ncolumns entries. + * opfamily[], and opcintype[] each have nkeycolumns entries. They do + * not contain any information about included attributes. + * + * sortopfamily[], reverse_sort[], and nulls_first[] have + * nkeycolumns entries, if the index is ordered; but if it is unordered, + * those pointers are NULL. + * + * Zeroes in the indexkeys[] array indicate index columns that are + * expressions; there is one element in indexprs for each such column. + * + * For an ordered index, reverse_sort[] and nulls_first[] describe the + * sort ordering of a forward indexscan; we can also consider a backward + * indexscan, which will generate the reverse ordering. + * + * The indexprs and indpred expressions have been run through + * prepqual.c and eval_const_expressions() for ease of matching to + * WHERE clauses. indpred is in implicit-AND form. + * + * indextlist is a TargetEntry list representing the index columns. + * It provides an equivalent base-relation Var for each simple column, + * and links to the matching indexprs element for each expression column. + * + * While most of these fields are filled when the IndexOptInfo is created + * (by plancat.c), indrestrictinfo and predOK are set later, in + * check_index_predicates(). + */ +#ifndef HAVE_INDEXOPTINFO_TYPEDEF +typedef struct IndexOptInfo IndexOptInfo; +#define HAVE_INDEXOPTINFO_TYPEDEF 1 +#endif + +struct IndexOptInfo +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + + /* OID of the index relation */ + Oid indexoid; + /* tablespace of index (not table) */ + Oid reltablespace; + /* back-link to index's table; don't print, else infinite recursion */ + RelOptInfo *rel pg_node_attr(read_write_ignore); + + /* + * index-size statistics (from pg_class and elsewhere) + */ + /* number of disk pages in index */ + BlockNumber pages; + /* number of index tuples in index */ + Cardinality tuples; + /* index tree height, or -1 if unknown */ + int tree_height; + + /* + * index descriptor information + */ + /* number of columns in index */ + int ncolumns; + /* number of key columns in index */ + int nkeycolumns; + + /* + * table column numbers of index's columns (both key and included + * columns), or 0 for expression columns + */ + int *indexkeys pg_node_attr(array_size(ncolumns)); + /* OIDs of collations of index columns */ + Oid *indexcollations pg_node_attr(array_size(nkeycolumns)); + /* OIDs of operator families for columns */ + Oid *opfamily pg_node_attr(array_size(nkeycolumns)); + /* OIDs of opclass declared input data types */ + Oid *opcintype pg_node_attr(array_size(nkeycolumns)); + /* OIDs of btree opfamilies, if orderable. NULL if partitioned index */ + Oid *sortopfamily pg_node_attr(array_size(nkeycolumns)); + /* is sort order descending? or NULL if partitioned index */ + bool *reverse_sort pg_node_attr(array_size(nkeycolumns)); + /* do NULLs come first in the sort order? or NULL if partitioned index */ + bool *nulls_first pg_node_attr(array_size(nkeycolumns)); + /* opclass-specific options for columns */ + bytea **opclassoptions pg_node_attr(read_write_ignore); + /* which index cols can be returned in an index-only scan? */ + bool *canreturn pg_node_attr(array_size(ncolumns)); + /* OID of the access method (in pg_am) */ + Oid relam; + + /* + * expressions for non-simple index columns; redundant to print since we + * print indextlist + */ + List *indexprs pg_node_attr(read_write_ignore); + /* predicate if a partial index, else NIL */ + List *indpred; + + /* targetlist representing index columns */ + List *indextlist; + + /* + * parent relation's baserestrictinfo list, less any conditions implied by + * the index's predicate (unless it's a target rel, see comments in + * check_index_predicates()) + */ + List *indrestrictinfo; + + /* true if index predicate matches query */ + bool predOK; + /* true if a unique index */ + bool unique; + /* is uniqueness enforced immediately? */ + bool immediate; + /* true if index doesn't really exist */ + bool hypothetical; + + /* + * Remaining fields are copied from the index AM's API struct + * (IndexAmRoutine). These fields are not set for partitioned indexes. + */ + bool amcanorderbyop; + bool amoptionalkey; + bool amsearcharray; + bool amsearchnulls; + /* does AM have amgettuple interface? */ + bool amhasgettuple; + /* does AM have amgetbitmap interface? */ + bool amhasgetbitmap; + bool amcanparallel; + /* does AM have ammarkpos interface? */ + bool amcanmarkpos; + /* AM's cost estimator */ + /* Rather than include amapi.h here, we declare amcostestimate like this */ + void (*amcostestimate) () pg_node_attr(read_write_ignore); +}; + +/* + * ForeignKeyOptInfo + * Per-foreign-key information for planning/optimization + * + * The per-FK-column arrays can be fixed-size because we allow at most + * INDEX_MAX_KEYS columns in a foreign key constraint. Each array has + * nkeys valid entries. + */ +typedef struct ForeignKeyOptInfo +{ + pg_node_attr(custom_read_write, no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + + /* + * Basic data about the foreign key (fetched from catalogs): + */ + + /* RT index of the referencing table */ + Index con_relid; + /* RT index of the referenced table */ + Index ref_relid; + /* number of columns in the foreign key */ + int nkeys; + /* cols in referencing table */ + AttrNumber conkey[INDEX_MAX_KEYS] pg_node_attr(array_size(nkeys)); + /* cols in referenced table */ + AttrNumber confkey[INDEX_MAX_KEYS] pg_node_attr(array_size(nkeys)); + /* PK = FK operator OIDs */ + Oid conpfeqop[INDEX_MAX_KEYS] pg_node_attr(array_size(nkeys)); + + /* + * Derived info about whether FK's equality conditions match the query: + */ + + /* # of FK cols matched by ECs */ + int nmatched_ec; + /* # of these ECs that are ec_has_const */ + int nconst_ec; + /* # of FK cols matched by non-EC rinfos */ + int nmatched_rcols; + /* total # of non-EC rinfos matched to FK */ + int nmatched_ri; + /* Pointer to eclass matching each column's condition, if there is one */ + struct EquivalenceClass *eclass[INDEX_MAX_KEYS]; + /* Pointer to eclass member for the referencing Var, if there is one */ + struct EquivalenceMember *fk_eclass_member[INDEX_MAX_KEYS]; + /* List of non-EC RestrictInfos matching each column's condition */ + List *rinfos[INDEX_MAX_KEYS]; +} ForeignKeyOptInfo; + +/* + * StatisticExtInfo + * Information about extended statistics for planning/optimization + * + * Each pg_statistic_ext row is represented by one or more nodes of this + * type, or even zero if ANALYZE has not computed them. + */ +typedef struct StatisticExtInfo +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + + /* OID of the statistics row */ + Oid statOid; + + /* includes child relations */ + bool inherit; + + /* back-link to statistic's table; don't print, else infinite recursion */ + RelOptInfo *rel pg_node_attr(read_write_ignore); + + /* statistics kind of this entry */ + char kind; + + /* attnums of the columns covered */ + Bitmapset *keys; + + /* expressions */ + List *exprs; +} StatisticExtInfo; + +/* + * JoinDomains + * + * A "join domain" defines the scope of applicability of deductions made via + * the EquivalenceClass mechanism. Roughly speaking, a join domain is a set + * of base+OJ relations that are inner-joined together. More precisely, it is + * the set of relations at which equalities deduced from an EquivalenceClass + * can be enforced or should be expected to hold. The topmost JoinDomain + * covers the whole query (so its jd_relids should equal all_query_rels). + * An outer join creates a new JoinDomain that includes all base+OJ relids + * within its nullable side, but (by convention) not the OJ's own relid. + * A FULL join creates two new JoinDomains, one for each side. + * + * Notice that a rel that is below outer join(s) will thus appear to belong + * to multiple join domains. However, any of its Vars that appear in + * EquivalenceClasses belonging to higher join domains will have nullingrel + * bits preventing them from being evaluated at the rel's scan level, so that + * we will not be able to derive enforceable-at-the-rel-scan-level clauses + * from such ECs. We define the join domain relid sets this way so that + * domains can be said to be "higher" or "lower" when one domain relid set + * includes another. + * + * The JoinDomains for a query are computed in deconstruct_jointree. + * We do not copy JoinDomain structs once made, so they can be compared + * for equality by simple pointer equality. + */ +typedef struct JoinDomain +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + + Relids jd_relids; /* all relids contained within the domain */ +} JoinDomain; + +/* + * EquivalenceClasses + * + * Whenever we identify a mergejoinable equality clause A = B that is + * not an outer-join clause, we create an EquivalenceClass containing + * the expressions A and B to record this knowledge. If we later find another + * equivalence B = C, we add C to the existing EquivalenceClass; this may + * require merging two existing EquivalenceClasses. At the end of the qual + * distribution process, we have sets of values that are known all transitively + * equal to each other, where "equal" is according to the rules of the btree + * operator family(s) shown in ec_opfamilies, as well as the collation shown + * by ec_collation. (We restrict an EC to contain only equalities whose + * operators belong to the same set of opfamilies. This could probably be + * relaxed, but for now it's not worth the trouble, since nearly all equality + * operators belong to only one btree opclass anyway. Similarly, we suppose + * that all or none of the input datatypes are collatable, so that a single + * collation value is sufficient.) + * + * Strictly speaking, deductions from an EquivalenceClass hold only within + * a "join domain", that is a set of relations that are innerjoined together + * (see JoinDomain above). For the most part we don't need to account for + * this explicitly, because equality clauses from different join domains + * will contain Vars that are not equal() because they have different + * nullingrel sets, and thus we will never falsely merge ECs from different + * join domains. But Var-free (pseudoconstant) expressions lack that safety + * feature. We handle that by marking "const" EC members with the JoinDomain + * of the clause they came from; two nominally-equal const members will be + * considered different if they came from different JoinDomains. This ensures + * no false EquivalenceClass merges will occur. + * + * We also use EquivalenceClasses as the base structure for PathKeys, letting + * us represent knowledge about different sort orderings being equivalent. + * Since every PathKey must reference an EquivalenceClass, we will end up + * with single-member EquivalenceClasses whenever a sort key expression has + * not been equivalenced to anything else. It is also possible that such an + * EquivalenceClass will contain a volatile expression ("ORDER BY random()"), + * which is a case that can't arise otherwise since clauses containing + * volatile functions are never considered mergejoinable. We mark such + * EquivalenceClasses specially to prevent them from being merged with + * ordinary EquivalenceClasses. Also, for volatile expressions we have + * to be careful to match the EquivalenceClass to the correct targetlist + * entry: consider SELECT random() AS a, random() AS b ... ORDER BY b,a. + * So we record the SortGroupRef of the originating sort clause. + * + * NB: if ec_merged isn't NULL, this class has been merged into another, and + * should be ignored in favor of using the pointed-to class. + * + * NB: EquivalenceClasses are never copied after creation. Therefore, + * copyObject() copies pointers to them as pointers, and equal() compares + * pointers to EquivalenceClasses via pointer equality. This is implemented + * by putting copy_as_scalar and equal_as_scalar attributes on fields that + * are pointers to EquivalenceClasses. The same goes for EquivalenceMembers. + */ +typedef struct EquivalenceClass +{ + pg_node_attr(custom_read_write, no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + + List *ec_opfamilies; /* btree operator family OIDs */ + Oid ec_collation; /* collation, if datatypes are collatable */ + List *ec_members; /* list of EquivalenceMembers */ + List *ec_sources; /* list of generating RestrictInfos */ + List *ec_derives; /* list of derived RestrictInfos */ + Relids ec_relids; /* all relids appearing in ec_members, except + * for child members (see below) */ + bool ec_has_const; /* any pseudoconstants in ec_members? */ + bool ec_has_volatile; /* the (sole) member is a volatile expr */ + bool ec_broken; /* failed to generate needed clauses? */ + Index ec_sortref; /* originating sortclause label, or 0 */ + Index ec_min_security; /* minimum security_level in ec_sources */ + Index ec_max_security; /* maximum security_level in ec_sources */ + struct EquivalenceClass *ec_merged; /* set if merged into another EC */ +} EquivalenceClass; + +/* + * If an EC contains a constant, any PathKey depending on it must be + * redundant, since there's only one possible value of the key. + */ +#define EC_MUST_BE_REDUNDANT(eclass) \ + ((eclass)->ec_has_const) + +/* + * EquivalenceMember - one member expression of an EquivalenceClass + * + * em_is_child signifies that this element was built by transposing a member + * for an appendrel parent relation to represent the corresponding expression + * for an appendrel child. These members are used for determining the + * pathkeys of scans on the child relation and for explicitly sorting the + * child when necessary to build a MergeAppend path for the whole appendrel + * tree. An em_is_child member has no impact on the properties of the EC as a + * whole; in particular the EC's ec_relids field does NOT include the child + * relation. An em_is_child member should never be marked em_is_const nor + * cause ec_has_const or ec_has_volatile to be set, either. Thus, em_is_child + * members are not really full-fledged members of the EC, but just reflections + * or doppelgangers of real members. Most operations on EquivalenceClasses + * should ignore em_is_child members, and those that don't should test + * em_relids to make sure they only consider relevant members. + * + * em_datatype is usually the same as exprType(em_expr), but can be + * different when dealing with a binary-compatible opfamily; in particular + * anyarray_ops would never work without this. Use em_datatype when + * looking up a specific btree operator to work with this expression. + */ +typedef struct EquivalenceMember +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + + Expr *em_expr; /* the expression represented */ + Relids em_relids; /* all relids appearing in em_expr */ + bool em_is_const; /* expression is pseudoconstant? */ + bool em_is_child; /* derived version for a child relation? */ + Oid em_datatype; /* the "nominal type" used by the opfamily */ + JoinDomain *em_jdomain; /* join domain containing the source clause */ + /* if em_is_child is true, this links to corresponding EM for top parent */ + struct EquivalenceMember *em_parent pg_node_attr(read_write_ignore); +} EquivalenceMember; + +/* + * PathKeys + * + * The sort ordering of a path is represented by a list of PathKey nodes. + * An empty list implies no known ordering. Otherwise the first item + * represents the primary sort key, the second the first secondary sort key, + * etc. The value being sorted is represented by linking to an + * EquivalenceClass containing that value and including pk_opfamily among its + * ec_opfamilies. The EquivalenceClass tells which collation to use, too. + * This is a convenient method because it makes it trivial to detect + * equivalent and closely-related orderings. (See optimizer/README for more + * information.) + * + * Note: pk_strategy is either BTLessStrategyNumber (for ASC) or + * BTGreaterStrategyNumber (for DESC). We assume that all ordering-capable + * index types will use btree-compatible strategy numbers. + */ +typedef struct PathKey +{ + pg_node_attr(no_read, no_query_jumble) + + NodeTag type; + + /* the value that is ordered */ + EquivalenceClass *pk_eclass pg_node_attr(copy_as_scalar, equal_as_scalar); + Oid pk_opfamily; /* btree opfamily defining the ordering */ + int pk_strategy; /* sort direction (ASC or DESC) */ + bool pk_nulls_first; /* do NULLs come before normal values? */ +} PathKey; + +/* + * VolatileFunctionStatus -- allows nodes to cache their + * contain_volatile_functions properties. VOLATILITY_UNKNOWN means not yet + * determined. + */ +typedef enum VolatileFunctionStatus +{ + VOLATILITY_UNKNOWN = 0, + VOLATILITY_VOLATILE, + VOLATILITY_NOVOLATILE +} VolatileFunctionStatus; + +/* + * PathTarget + * + * This struct contains what we need to know during planning about the + * targetlist (output columns) that a Path will compute. Each RelOptInfo + * includes a default PathTarget, which its individual Paths may simply + * reference. However, in some cases a Path may compute outputs different + * from other Paths, and in that case we make a custom PathTarget for it. + * For example, an indexscan might return index expressions that would + * otherwise need to be explicitly calculated. (Note also that "upper" + * relations generally don't have useful default PathTargets.) + * + * exprs contains bare expressions; they do not have TargetEntry nodes on top, + * though those will appear in finished Plans. + * + * sortgrouprefs[] is an array of the same length as exprs, containing the + * corresponding sort/group refnos, or zeroes for expressions not referenced + * by sort/group clauses. If sortgrouprefs is NULL (which it generally is in + * RelOptInfo.reltarget targets; only upper-level Paths contain this info), + * we have not identified sort/group columns in this tlist. This allows us to + * deal with sort/group refnos when needed with less expense than including + * TargetEntry nodes in the exprs list. + */ +typedef struct PathTarget +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + + /* list of expressions to be computed */ + List *exprs; + + /* corresponding sort/group refnos, or 0 */ + Index *sortgrouprefs pg_node_attr(array_size(exprs)); + + /* cost of evaluating the expressions */ + QualCost cost; + + /* estimated avg width of result tuples */ + int width; + + /* indicates if exprs contain any volatile functions */ + VolatileFunctionStatus has_volatile_expr; +} PathTarget; + +/* Convenience macro to get a sort/group refno from a PathTarget */ +#define get_pathtarget_sortgroupref(target, colno) \ + ((target)->sortgrouprefs ? (target)->sortgrouprefs[colno] : (Index) 0) + + +/* + * ParamPathInfo + * + * All parameterized paths for a given relation with given required outer rels + * link to a single ParamPathInfo, which stores common information such as + * the estimated rowcount for this parameterization. We do this partly to + * avoid recalculations, but mostly to ensure that the estimated rowcount + * is in fact the same for every such path. + * + * Note: ppi_clauses is only used in ParamPathInfos for base relation paths; + * in join cases it's NIL because the set of relevant clauses varies depending + * on how the join is formed. The relevant clauses will appear in each + * parameterized join path's joinrestrictinfo list, instead. ParamPathInfos + * for append relations don't bother with this, either. + * + * ppi_serials is the set of rinfo_serial numbers for quals that are enforced + * by this path. As with ppi_clauses, it's only maintained for baserels. + * (We could construct it on-the-fly from ppi_clauses, but it seems better + * to materialize a copy.) + */ +typedef struct ParamPathInfo +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + + Relids ppi_req_outer; /* rels supplying parameters used by path */ + Cardinality ppi_rows; /* estimated number of result tuples */ + List *ppi_clauses; /* join clauses available from outer rels */ + Bitmapset *ppi_serials; /* set of rinfo_serial for enforced quals */ +} ParamPathInfo; + + +/* + * Type "Path" is used as-is for sequential-scan paths, as well as some other + * simple plan types that we don't need any extra information in the path for. + * For other path types it is the first component of a larger struct. + * + * "pathtype" is the NodeTag of the Plan node we could build from this Path. + * It is partially redundant with the Path's NodeTag, but allows us to use + * the same Path type for multiple Plan types when there is no need to + * distinguish the Plan type during path processing. + * + * "parent" identifies the relation this Path scans, and "pathtarget" + * describes the precise set of output columns the Path would compute. + * In simple cases all Paths for a given rel share the same targetlist, + * which we represent by having path->pathtarget equal to parent->reltarget. + * + * "param_info", if not NULL, links to a ParamPathInfo that identifies outer + * relation(s) that provide parameter values to each scan of this path. + * That means this path can only be joined to those rels by means of nestloop + * joins with this path on the inside. Also note that a parameterized path + * is responsible for testing all "movable" joinclauses involving this rel + * and the specified outer rel(s). + * + * "rows" is the same as parent->rows in simple paths, but in parameterized + * paths and UniquePaths it can be less than parent->rows, reflecting the + * fact that we've filtered by extra join conditions or removed duplicates. + * + * "pathkeys" is a List of PathKey nodes (see above), describing the sort + * ordering of the path's output rows. + * + * We do not support copying Path trees, mainly because the circular linkages + * between RelOptInfo and Path nodes can't be handled easily in a simple + * depth-first traversal. We also don't have read support at the moment. + */ +typedef struct Path +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + + /* tag identifying scan/join method */ + NodeTag pathtype; + + /* + * the relation this path can build + * + * We do NOT print the parent, else we'd be in infinite recursion. We can + * print the parent's relids for identification purposes, though. + */ + RelOptInfo *parent pg_node_attr(write_only_relids); + + /* + * list of Vars/Exprs, cost, width + * + * We print the pathtarget only if it's not the default one for the rel. + */ + PathTarget *pathtarget pg_node_attr(write_only_nondefault_pathtarget); + + /* + * parameterization info, or NULL if none + * + * We do not print the whole of param_info, since it's printed via + * RelOptInfo; it's sufficient and less cluttering to print just the + * required outer relids. + */ + ParamPathInfo *param_info pg_node_attr(write_only_req_outer); + + /* engage parallel-aware logic? */ + bool parallel_aware; + /* OK to use as part of parallel plan? */ + bool parallel_safe; + /* desired # of workers; 0 = not parallel */ + int parallel_workers; + + /* estimated size/costs for path (see costsize.c for more info) */ + Cardinality rows; /* estimated number of result tuples */ + Cost startup_cost; /* cost expended before fetching any tuples */ + Cost total_cost; /* total cost (assuming all tuples fetched) */ + + /* sort ordering of path's output; a List of PathKey nodes; see above */ + List *pathkeys; +} Path; + +/* Macro for extracting a path's parameterization relids; beware double eval */ +#define PATH_REQ_OUTER(path) \ + ((path)->param_info ? (path)->param_info->ppi_req_outer : (Relids) NULL) + +/*---------- + * IndexPath represents an index scan over a single index. + * + * This struct is used for both regular indexscans and index-only scans; + * path.pathtype is T_IndexScan or T_IndexOnlyScan to show which is meant. + * + * 'indexinfo' is the index to be scanned. + * + * 'indexclauses' is a list of IndexClause nodes, each representing one + * index-checkable restriction, with implicit AND semantics across the list. + * An empty list implies a full index scan. + * + * 'indexorderbys', if not NIL, is a list of ORDER BY expressions that have + * been found to be usable as ordering operators for an amcanorderbyop index. + * The list must match the path's pathkeys, ie, one expression per pathkey + * in the same order. These are not RestrictInfos, just bare expressions, + * since they generally won't yield booleans. It's guaranteed that each + * expression has the index key on the left side of the operator. + * + * 'indexorderbycols' is an integer list of index column numbers (zero-based) + * of the same length as 'indexorderbys', showing which index column each + * ORDER BY expression is meant to be used with. (There is no restriction + * on which index column each ORDER BY can be used with.) + * + * 'indexscandir' is one of: + * ForwardScanDirection: forward scan of an index + * BackwardScanDirection: backward scan of an ordered index + * Unordered indexes will always have an indexscandir of ForwardScanDirection. + * + * 'indextotalcost' and 'indexselectivity' are saved in the IndexPath so that + * we need not recompute them when considering using the same index in a + * bitmap index/heap scan (see BitmapHeapPath). The costs of the IndexPath + * itself represent the costs of an IndexScan or IndexOnlyScan plan type. + *---------- + */ +typedef struct IndexPath +{ + Path path; + IndexOptInfo *indexinfo; + List *indexclauses; + List *indexorderbys; + List *indexorderbycols; + ScanDirection indexscandir; + Cost indextotalcost; + Selectivity indexselectivity; +} IndexPath; + +/* + * Each IndexClause references a RestrictInfo node from the query's WHERE + * or JOIN conditions, and shows how that restriction can be applied to + * the particular index. We support both indexclauses that are directly + * usable by the index machinery, which are typically of the form + * "indexcol OP pseudoconstant", and those from which an indexable qual + * can be derived. The simplest such transformation is that a clause + * of the form "pseudoconstant OP indexcol" can be commuted to produce an + * indexable qual (the index machinery expects the indexcol to be on the + * left always). Another example is that we might be able to extract an + * indexable range condition from a LIKE condition, as in "x LIKE 'foo%bar'" + * giving rise to "x >= 'foo' AND x < 'fop'". Derivation of such lossy + * conditions is done by a planner support function attached to the + * indexclause's top-level function or operator. + * + * indexquals is a list of RestrictInfos for the directly-usable index + * conditions associated with this IndexClause. In the simplest case + * it's a one-element list whose member is iclause->rinfo. Otherwise, + * it contains one or more directly-usable indexqual conditions extracted + * from the given clause. The 'lossy' flag indicates whether the + * indexquals are semantically equivalent to the original clause, or + * represent a weaker condition. + * + * Normally, indexcol is the index of the single index column the clause + * works on, and indexcols is NIL. But if the clause is a RowCompareExpr, + * indexcol is the index of the leading column, and indexcols is a list of + * all the affected columns. (Note that indexcols matches up with the + * columns of the actual indexable RowCompareExpr in indexquals, which + * might be different from the original in rinfo.) + * + * An IndexPath's IndexClause list is required to be ordered by index + * column, i.e. the indexcol values must form a nondecreasing sequence. + * (The order of multiple clauses for the same index column is unspecified.) + */ +typedef struct IndexClause +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + struct RestrictInfo *rinfo; /* original restriction or join clause */ + List *indexquals; /* indexqual(s) derived from it */ + bool lossy; /* are indexquals a lossy version of clause? */ + AttrNumber indexcol; /* index column the clause uses (zero-based) */ + List *indexcols; /* multiple index columns, if RowCompare */ +} IndexClause; + +/* + * BitmapHeapPath represents one or more indexscans that generate TID bitmaps + * instead of directly accessing the heap, followed by AND/OR combinations + * to produce a single bitmap, followed by a heap scan that uses the bitmap. + * Note that the output is always considered unordered, since it will come + * out in physical heap order no matter what the underlying indexes did. + * + * The individual indexscans are represented by IndexPath nodes, and any + * logic on top of them is represented by a tree of BitmapAndPath and + * BitmapOrPath nodes. Notice that we can use the same IndexPath node both + * to represent a regular (or index-only) index scan plan, and as the child + * of a BitmapHeapPath that represents scanning the same index using a + * BitmapIndexScan. The startup_cost and total_cost figures of an IndexPath + * always represent the costs to use it as a regular (or index-only) + * IndexScan. The costs of a BitmapIndexScan can be computed using the + * IndexPath's indextotalcost and indexselectivity. + */ +typedef struct BitmapHeapPath +{ + Path path; + Path *bitmapqual; /* IndexPath, BitmapAndPath, BitmapOrPath */ +} BitmapHeapPath; + +/* + * BitmapAndPath represents a BitmapAnd plan node; it can only appear as + * part of the substructure of a BitmapHeapPath. The Path structure is + * a bit more heavyweight than we really need for this, but for simplicity + * we make it a derivative of Path anyway. + */ +typedef struct BitmapAndPath +{ + Path path; + List *bitmapquals; /* IndexPaths and BitmapOrPaths */ + Selectivity bitmapselectivity; +} BitmapAndPath; + +/* + * BitmapOrPath represents a BitmapOr plan node; it can only appear as + * part of the substructure of a BitmapHeapPath. The Path structure is + * a bit more heavyweight than we really need for this, but for simplicity + * we make it a derivative of Path anyway. + */ +typedef struct BitmapOrPath +{ + Path path; + List *bitmapquals; /* IndexPaths and BitmapAndPaths */ + Selectivity bitmapselectivity; +} BitmapOrPath; + +/* + * TidPath represents a scan by TID + * + * tidquals is an implicitly OR'ed list of qual expressions of the form + * "CTID = pseudoconstant", or "CTID = ANY(pseudoconstant_array)", + * or a CurrentOfExpr for the relation. + */ +typedef struct TidPath +{ + Path path; + List *tidquals; /* qual(s) involving CTID = something */ +} TidPath; + +/* + * TidRangePath represents a scan by a contiguous range of TIDs + * + * tidrangequals is an implicitly AND'ed list of qual expressions of the form + * "CTID relop pseudoconstant", where relop is one of >,>=,<,<=. + */ +typedef struct TidRangePath +{ + Path path; + List *tidrangequals; +} TidRangePath; + +/* + * SubqueryScanPath represents a scan of an unflattened subquery-in-FROM + * + * Note that the subpath comes from a different planning domain; for example + * RTE indexes within it mean something different from those known to the + * SubqueryScanPath. path.parent->subroot is the planning context needed to + * interpret the subpath. + */ +typedef struct SubqueryScanPath +{ + Path path; + Path *subpath; /* path representing subquery execution */ +} SubqueryScanPath; + +/* + * ForeignPath represents a potential scan of a foreign table, foreign join + * or foreign upper-relation. + * + * fdw_private stores FDW private data about the scan. While fdw_private is + * not actually touched by the core code during normal operations, it's + * generally a good idea to use a representation that can be dumped by + * nodeToString(), so that you can examine the structure during debugging + * with tools like pprint(). + */ +typedef struct ForeignPath +{ + Path path; + Path *fdw_outerpath; + List *fdw_private; +} ForeignPath; + +/* + * CustomPath represents a table scan or a table join done by some out-of-core + * extension. + * + * We provide a set of hooks here - which the provider must take care to set + * up correctly - to allow extensions to supply their own methods of scanning + * a relation or joing relations. For example, a provider might provide GPU + * acceleration, a cache-based scan, or some other kind of logic we haven't + * dreamed up yet. + * + * CustomPaths can be injected into the planning process for a base or join + * relation by set_rel_pathlist_hook or set_join_pathlist_hook functions, + * respectively. + * + * Core code must avoid assuming that the CustomPath is only as large as + * the structure declared here; providers are allowed to make it the first + * element in a larger structure. (Since the planner never copies Paths, + * this doesn't add any complication.) However, for consistency with the + * FDW case, we provide a "custom_private" field in CustomPath; providers + * may prefer to use that rather than define another struct type. + */ + +struct CustomPathMethods; + +typedef struct CustomPath +{ + Path path; + uint32 flags; /* mask of CUSTOMPATH_* flags, see + * nodes/extensible.h */ + List *custom_paths; /* list of child Path nodes, if any */ + List *custom_private; + const struct CustomPathMethods *methods; +} CustomPath; + +/* + * AppendPath represents an Append plan, ie, successive execution of + * several member plans. + * + * For partial Append, 'subpaths' contains non-partial subpaths followed by + * partial subpaths. + * + * Note: it is possible for "subpaths" to contain only one, or even no, + * elements. These cases are optimized during create_append_plan. + * In particular, an AppendPath with no subpaths is a "dummy" path that + * is created to represent the case that a relation is provably empty. + * (This is a convenient representation because it means that when we build + * an appendrel and find that all its children have been excluded, no extra + * action is needed to recognize the relation as dummy.) + */ +typedef struct AppendPath +{ + Path path; + List *subpaths; /* list of component Paths */ + /* Index of first partial path in subpaths; list_length(subpaths) if none */ + int first_partial_path; + Cardinality limit_tuples; /* hard limit on output tuples, or -1 */ +} AppendPath; + +#define IS_DUMMY_APPEND(p) \ + (IsA((p), AppendPath) && ((AppendPath *) (p))->subpaths == NIL) + +/* + * A relation that's been proven empty will have one path that is dummy + * (but might have projection paths on top). For historical reasons, + * this is provided as a macro that wraps is_dummy_rel(). + */ +#define IS_DUMMY_REL(r) is_dummy_rel(r) +extern bool is_dummy_rel(RelOptInfo *rel); + +/* + * MergeAppendPath represents a MergeAppend plan, ie, the merging of sorted + * results from several member plans to produce similarly-sorted output. + */ +typedef struct MergeAppendPath +{ + Path path; + List *subpaths; /* list of component Paths */ + Cardinality limit_tuples; /* hard limit on output tuples, or -1 */ +} MergeAppendPath; + +/* + * GroupResultPath represents use of a Result plan node to compute the + * output of a degenerate GROUP BY case, wherein we know we should produce + * exactly one row, which might then be filtered by a HAVING qual. + * + * Note that quals is a list of bare clauses, not RestrictInfos. + */ +typedef struct GroupResultPath +{ + Path path; + List *quals; +} GroupResultPath; + +/* + * MaterialPath represents use of a Material plan node, i.e., caching of + * the output of its subpath. This is used when the subpath is expensive + * and needs to be scanned repeatedly, or when we need mark/restore ability + * and the subpath doesn't have it. + */ +typedef struct MaterialPath +{ + Path path; + Path *subpath; +} MaterialPath; + +/* + * MemoizePath represents a Memoize plan node, i.e., a cache that caches + * tuples from parameterized paths to save the underlying node from having to + * be rescanned for parameter values which are already cached. + */ +typedef struct MemoizePath +{ + Path path; + Path *subpath; /* outerpath to cache tuples from */ + List *hash_operators; /* OIDs of hash equality ops for cache keys */ + List *param_exprs; /* expressions that are cache keys */ + bool singlerow; /* true if the cache entry is to be marked as + * complete after caching the first record. */ + bool binary_mode; /* true when cache key should be compared bit + * by bit, false when using hash equality ops */ + Cardinality calls; /* expected number of rescans */ + uint32 est_entries; /* The maximum number of entries that the + * planner expects will fit in the cache, or 0 + * if unknown */ +} MemoizePath; + +/* + * UniquePath represents elimination of distinct rows from the output of + * its subpath. + * + * This can represent significantly different plans: either hash-based or + * sort-based implementation, or a no-op if the input path can be proven + * distinct already. The decision is sufficiently localized that it's not + * worth having separate Path node types. (Note: in the no-op case, we could + * eliminate the UniquePath node entirely and just return the subpath; but + * it's convenient to have a UniquePath in the path tree to signal upper-level + * routines that the input is known distinct.) + */ +typedef enum UniquePathMethod +{ + UNIQUE_PATH_NOOP, /* input is known unique already */ + UNIQUE_PATH_HASH, /* use hashing */ + UNIQUE_PATH_SORT /* use sorting */ +} UniquePathMethod; + +typedef struct UniquePath +{ + Path path; + Path *subpath; + UniquePathMethod umethod; + List *in_operators; /* equality operators of the IN clause */ + List *uniq_exprs; /* expressions to be made unique */ +} UniquePath; + +/* + * GatherPath runs several copies of a plan in parallel and collects the + * results. The parallel leader may also execute the plan, unless the + * single_copy flag is set. + */ +typedef struct GatherPath +{ + Path path; + Path *subpath; /* path for each worker */ + bool single_copy; /* don't execute path more than once */ + int num_workers; /* number of workers sought to help */ +} GatherPath; + +/* + * GatherMergePath runs several copies of a plan in parallel and collects + * the results, preserving their common sort order. + */ +typedef struct GatherMergePath +{ + Path path; + Path *subpath; /* path for each worker */ + int num_workers; /* number of workers sought to help */ +} GatherMergePath; + + +/* + * All join-type paths share these fields. + */ + +typedef struct JoinPath +{ + pg_node_attr(abstract) + + Path path; + + JoinType jointype; + + bool inner_unique; /* each outer tuple provably matches no more + * than one inner tuple */ + + Path *outerjoinpath; /* path for the outer side of the join */ + Path *innerjoinpath; /* path for the inner side of the join */ + + List *joinrestrictinfo; /* RestrictInfos to apply to join */ + + /* + * See the notes for RelOptInfo and ParamPathInfo to understand why + * joinrestrictinfo is needed in JoinPath, and can't be merged into the + * parent RelOptInfo. + */ +} JoinPath; + +/* + * A nested-loop path needs no special fields. + */ + +typedef struct NestPath +{ + JoinPath jpath; +} NestPath; + +/* + * A mergejoin path has these fields. + * + * Unlike other path types, a MergePath node doesn't represent just a single + * run-time plan node: it can represent up to four. Aside from the MergeJoin + * node itself, there can be a Sort node for the outer input, a Sort node + * for the inner input, and/or a Material node for the inner input. We could + * represent these nodes by separate path nodes, but considering how many + * different merge paths are investigated during a complex join problem, + * it seems better to avoid unnecessary palloc overhead. + * + * path_mergeclauses lists the clauses (in the form of RestrictInfos) + * that will be used in the merge. + * + * Note that the mergeclauses are a subset of the parent relation's + * restriction-clause list. Any join clauses that are not mergejoinable + * appear only in the parent's restrict list, and must be checked by a + * qpqual at execution time. + * + * outersortkeys (resp. innersortkeys) is NIL if the outer path + * (resp. inner path) is already ordered appropriately for the + * mergejoin. If it is not NIL then it is a PathKeys list describing + * the ordering that must be created by an explicit Sort node. + * + * skip_mark_restore is true if the executor need not do mark/restore calls. + * Mark/restore overhead is usually required, but can be skipped if we know + * that the executor need find only one match per outer tuple, and that the + * mergeclauses are sufficient to identify a match. In such cases the + * executor can immediately advance the outer relation after processing a + * match, and therefore it need never back up the inner relation. + * + * materialize_inner is true if a Material node should be placed atop the + * inner input. This may appear with or without an inner Sort step. + */ + +typedef struct MergePath +{ + JoinPath jpath; + List *path_mergeclauses; /* join clauses to be used for merge */ + List *outersortkeys; /* keys for explicit sort, if any */ + List *innersortkeys; /* keys for explicit sort, if any */ + bool skip_mark_restore; /* can executor skip mark/restore? */ + bool materialize_inner; /* add Materialize to inner? */ +} MergePath; + +/* + * A hashjoin path has these fields. + * + * The remarks above for mergeclauses apply for hashclauses as well. + * + * Hashjoin does not care what order its inputs appear in, so we have + * no need for sortkeys. + */ + +typedef struct HashPath +{ + JoinPath jpath; + List *path_hashclauses; /* join clauses used for hashing */ + int num_batches; /* number of batches expected */ + Cardinality inner_rows_total; /* total inner rows expected */ +} HashPath; + +/* + * ProjectionPath represents a projection (that is, targetlist computation) + * + * Nominally, this path node represents using a Result plan node to do a + * projection step. However, if the input plan node supports projection, + * we can just modify its output targetlist to do the required calculations + * directly, and not need a Result. In some places in the planner we can just + * jam the desired PathTarget into the input path node (and adjust its cost + * accordingly), so we don't need a ProjectionPath. But in other places + * it's necessary to not modify the input path node, so we need a separate + * ProjectionPath node, which is marked dummy to indicate that we intend to + * assign the work to the input plan node. The estimated cost for the + * ProjectionPath node will account for whether a Result will be used or not. + */ +typedef struct ProjectionPath +{ + Path path; + Path *subpath; /* path representing input source */ + bool dummypp; /* true if no separate Result is needed */ +} ProjectionPath; + +/* + * ProjectSetPath represents evaluation of a targetlist that includes + * set-returning function(s), which will need to be implemented by a + * ProjectSet plan node. + */ +typedef struct ProjectSetPath +{ + Path path; + Path *subpath; /* path representing input source */ +} ProjectSetPath; + +/* + * SortPath represents an explicit sort step + * + * The sort keys are, by definition, the same as path.pathkeys. + * + * Note: the Sort plan node cannot project, so path.pathtarget must be the + * same as the input's pathtarget. + */ +typedef struct SortPath +{ + Path path; + Path *subpath; /* path representing input source */ +} SortPath; + +/* + * IncrementalSortPath represents an incremental sort step + * + * This is like a regular sort, except some leading key columns are assumed + * to be ordered already. + */ +typedef struct IncrementalSortPath +{ + SortPath spath; + int nPresortedCols; /* number of presorted columns */ +} IncrementalSortPath; + +/* + * GroupPath represents grouping (of presorted input) + * + * groupClause represents the columns to be grouped on; the input path + * must be at least that well sorted. + * + * We can also apply a qual to the grouped rows (equivalent of HAVING) + */ +typedef struct GroupPath +{ + Path path; + Path *subpath; /* path representing input source */ + List *groupClause; /* a list of SortGroupClause's */ + List *qual; /* quals (HAVING quals), if any */ +} GroupPath; + +/* + * UpperUniquePath represents adjacent-duplicate removal (in presorted input) + * + * The columns to be compared are the first numkeys columns of the path's + * pathkeys. The input is presumed already sorted that way. + */ +typedef struct UpperUniquePath +{ + Path path; + Path *subpath; /* path representing input source */ + int numkeys; /* number of pathkey columns to compare */ +} UpperUniquePath; + +/* + * AggPath represents generic computation of aggregate functions + * + * This may involve plain grouping (but not grouping sets), using either + * sorted or hashed grouping; for the AGG_SORTED case, the input must be + * appropriately presorted. + */ +typedef struct AggPath +{ + Path path; + Path *subpath; /* path representing input source */ + AggStrategy aggstrategy; /* basic strategy, see nodes.h */ + AggSplit aggsplit; /* agg-splitting mode, see nodes.h */ + Cardinality numGroups; /* estimated number of groups in input */ + uint64 transitionSpace; /* for pass-by-ref transition data */ + List *groupClause; /* a list of SortGroupClause's */ + List *qual; /* quals (HAVING quals), if any */ +} AggPath; + +/* + * Various annotations used for grouping sets in the planner. + */ + +typedef struct GroupingSetData +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + List *set; /* grouping set as list of sortgrouprefs */ + Cardinality numGroups; /* est. number of result groups */ +} GroupingSetData; + +typedef struct RollupData +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + List *groupClause; /* applicable subset of parse->groupClause */ + List *gsets; /* lists of integer indexes into groupClause */ + List *gsets_data; /* list of GroupingSetData */ + Cardinality numGroups; /* est. number of result groups */ + bool hashable; /* can be hashed */ + bool is_hashed; /* to be implemented as a hashagg */ +} RollupData; + +/* + * GroupingSetsPath represents a GROUPING SETS aggregation + */ + +typedef struct GroupingSetsPath +{ + Path path; + Path *subpath; /* path representing input source */ + AggStrategy aggstrategy; /* basic strategy */ + List *rollups; /* list of RollupData */ + List *qual; /* quals (HAVING quals), if any */ + uint64 transitionSpace; /* for pass-by-ref transition data */ +} GroupingSetsPath; + +/* + * MinMaxAggPath represents computation of MIN/MAX aggregates from indexes + */ +typedef struct MinMaxAggPath +{ + Path path; + List *mmaggregates; /* list of MinMaxAggInfo */ + List *quals; /* HAVING quals, if any */ +} MinMaxAggPath; + +/* + * WindowAggPath represents generic computation of window functions + */ +typedef struct WindowAggPath +{ + Path path; + Path *subpath; /* path representing input source */ + WindowClause *winclause; /* WindowClause we'll be using */ + List *qual; /* lower-level WindowAgg runconditions */ + bool topwindow; /* false for all apart from the WindowAgg + * that's closest to the root of the plan */ +} WindowAggPath; + +/* + * SetOpPath represents a set-operation, that is INTERSECT or EXCEPT + */ +typedef struct SetOpPath +{ + Path path; + Path *subpath; /* path representing input source */ + SetOpCmd cmd; /* what to do, see nodes.h */ + SetOpStrategy strategy; /* how to do it, see nodes.h */ + List *distinctList; /* SortGroupClauses identifying target cols */ + AttrNumber flagColIdx; /* where is the flag column, if any */ + int firstFlag; /* flag value for first input relation */ + Cardinality numGroups; /* estimated number of groups in input */ +} SetOpPath; + +/* + * RecursiveUnionPath represents a recursive UNION node + */ +typedef struct RecursiveUnionPath +{ + Path path; + Path *leftpath; /* paths representing input sources */ + Path *rightpath; + List *distinctList; /* SortGroupClauses identifying target cols */ + int wtParam; /* ID of Param representing work table */ + Cardinality numGroups; /* estimated number of groups in input */ +} RecursiveUnionPath; + +/* + * LockRowsPath represents acquiring row locks for SELECT FOR UPDATE/SHARE + */ +typedef struct LockRowsPath +{ + Path path; + Path *subpath; /* path representing input source */ + List *rowMarks; /* a list of PlanRowMark's */ + int epqParam; /* ID of Param for EvalPlanQual re-eval */ +} LockRowsPath; + +/* + * ModifyTablePath represents performing INSERT/UPDATE/DELETE/MERGE + * + * We represent most things that will be in the ModifyTable plan node + * literally, except we have a child Path not Plan. But analysis of the + * OnConflictExpr is deferred to createplan.c, as is collection of FDW data. + */ +typedef struct ModifyTablePath +{ + Path path; + Path *subpath; /* Path producing source data */ + CmdType operation; /* INSERT, UPDATE, DELETE, or MERGE */ + bool canSetTag; /* do we set the command tag/es_processed? */ + Index nominalRelation; /* Parent RT index for use of EXPLAIN */ + Index rootRelation; /* Root RT index, if partitioned/inherited */ + bool partColsUpdated; /* some part key in hierarchy updated? */ + List *resultRelations; /* integer list of RT indexes */ + List *updateColnosLists; /* per-target-table update_colnos lists */ + List *withCheckOptionLists; /* per-target-table WCO lists */ + List *returningLists; /* per-target-table RETURNING tlists */ + List *rowMarks; /* PlanRowMarks (non-locking only) */ + OnConflictExpr *onconflict; /* ON CONFLICT clause, or NULL */ + int epqParam; /* ID of Param for EvalPlanQual re-eval */ + List *mergeActionLists; /* per-target-table lists of actions for + * MERGE */ +} ModifyTablePath; + +/* + * LimitPath represents applying LIMIT/OFFSET restrictions + */ +typedef struct LimitPath +{ + Path path; + Path *subpath; /* path representing input source */ + Node *limitOffset; /* OFFSET parameter, or NULL if none */ + Node *limitCount; /* COUNT parameter, or NULL if none */ + LimitOption limitOption; /* FETCH FIRST with ties or exact number */ +} LimitPath; + + +/* + * Restriction clause info. + * + * We create one of these for each AND sub-clause of a restriction condition + * (WHERE or JOIN/ON clause). Since the restriction clauses are logically + * ANDed, we can use any one of them or any subset of them to filter out + * tuples, without having to evaluate the rest. The RestrictInfo node itself + * stores data used by the optimizer while choosing the best query plan. + * + * If a restriction clause references a single base relation, it will appear + * in the baserestrictinfo list of the RelOptInfo for that base rel. + * + * If a restriction clause references more than one base+OJ relation, it will + * appear in the joininfo list of every RelOptInfo that describes a strict + * subset of the relations mentioned in the clause. The joininfo lists are + * used to drive join tree building by selecting plausible join candidates. + * The clause cannot actually be applied until we have built a join rel + * containing all the relations it references, however. + * + * When we construct a join rel that includes all the relations referenced + * in a multi-relation restriction clause, we place that clause into the + * joinrestrictinfo lists of paths for the join rel, if neither left nor + * right sub-path includes all relations referenced in the clause. The clause + * will be applied at that join level, and will not propagate any further up + * the join tree. (Note: the "predicate migration" code was once intended to + * push restriction clauses up and down the plan tree based on evaluation + * costs, but it's dead code and is unlikely to be resurrected in the + * foreseeable future.) + * + * Note that in the presence of more than two rels, a multi-rel restriction + * might reach different heights in the join tree depending on the join + * sequence we use. So, these clauses cannot be associated directly with + * the join RelOptInfo, but must be kept track of on a per-join-path basis. + * + * RestrictInfos that represent equivalence conditions (i.e., mergejoinable + * equalities that are not outerjoin-delayed) are handled a bit differently. + * Initially we attach them to the EquivalenceClasses that are derived from + * them. When we construct a scan or join path, we look through all the + * EquivalenceClasses and generate derived RestrictInfos representing the + * minimal set of conditions that need to be checked for this particular scan + * or join to enforce that all members of each EquivalenceClass are in fact + * equal in all rows emitted by the scan or join. + * + * The clause_relids field lists the base plus outer-join RT indexes that + * actually appear in the clause. required_relids lists the minimum set of + * relids needed to evaluate the clause; while this is often equal to + * clause_relids, it can be more. We will add relids to required_relids when + * we need to force an outer join ON clause to be evaluated exactly at the + * level of the outer join, which is true except when it is a "degenerate" + * condition that references only Vars from the nullable side of the join. + * + * RestrictInfo nodes contain a flag to indicate whether a qual has been + * pushed down to a lower level than its original syntactic placement in the + * join tree would suggest. If an outer join prevents us from pushing a qual + * down to its "natural" semantic level (the level associated with just the + * base rels used in the qual) then we mark the qual with a "required_relids" + * value including more than just the base rels it actually uses. By + * pretending that the qual references all the rels required to form the outer + * join, we prevent it from being evaluated below the outer join's joinrel. + * When we do form the outer join's joinrel, we still need to distinguish + * those quals that are actually in that join's JOIN/ON condition from those + * that appeared elsewhere in the tree and were pushed down to the join rel + * because they used no other rels. That's what the is_pushed_down flag is + * for; it tells us that a qual is not an OUTER JOIN qual for the set of base + * rels listed in required_relids. A clause that originally came from WHERE + * or an INNER JOIN condition will *always* have its is_pushed_down flag set. + * It's possible for an OUTER JOIN clause to be marked is_pushed_down too, + * if we decide that it can be pushed down into the nullable side of the join. + * In that case it acts as a plain filter qual for wherever it gets evaluated. + * (In short, is_pushed_down is only false for non-degenerate outer join + * conditions. Possibly we should rename it to reflect that meaning? But + * see also the comments for RINFO_IS_PUSHED_DOWN, below.) + * + * There is also an incompatible_relids field, which is a set of outer-join + * relids above which we cannot evaluate the clause (because they might null + * Vars it uses that should not be nulled yet). In principle this could be + * filled in any RestrictInfo as the set of OJ relids that appear above the + * clause and null Vars that it uses. In practice we only bother to populate + * it for "clone" clauses, as it's currently only needed to prevent multiple + * clones of the same clause from being accepted for evaluation at the same + * join level. + * + * There is also an outer_relids field, which is NULL except for outer join + * clauses; for those, it is the set of relids on the outer side of the + * clause's outer join. (These are rels that the clause cannot be applied to + * in parameterized scans, since pushing it into the join's outer side would + * lead to wrong answers.) + * + * To handle security-barrier conditions efficiently, we mark RestrictInfo + * nodes with a security_level field, in which higher values identify clauses + * coming from less-trusted sources. The exact semantics are that a clause + * cannot be evaluated before another clause with a lower security_level value + * unless the first clause is leakproof. As with outer-join clauses, this + * creates a reason for clauses to sometimes need to be evaluated higher in + * the join tree than their contents would suggest; and even at a single plan + * node, this rule constrains the order of application of clauses. + * + * In general, the referenced clause might be arbitrarily complex. The + * kinds of clauses we can handle as indexscan quals, mergejoin clauses, + * or hashjoin clauses are limited (e.g., no volatile functions). The code + * for each kind of path is responsible for identifying the restrict clauses + * it can use and ignoring the rest. Clauses not implemented by an indexscan, + * mergejoin, or hashjoin will be placed in the plan qual or joinqual field + * of the finished Plan node, where they will be enforced by general-purpose + * qual-expression-evaluation code. (But we are still entitled to count + * their selectivity when estimating the result tuple count, if we + * can guess what it is...) + * + * When the referenced clause is an OR clause, we generate a modified copy + * in which additional RestrictInfo nodes are inserted below the top-level + * OR/AND structure. This is a convenience for OR indexscan processing: + * indexquals taken from either the top level or an OR subclause will have + * associated RestrictInfo nodes. + * + * The can_join flag is set true if the clause looks potentially useful as + * a merge or hash join clause, that is if it is a binary opclause with + * nonoverlapping sets of relids referenced in the left and right sides. + * (Whether the operator is actually merge or hash joinable isn't checked, + * however.) + * + * The pseudoconstant flag is set true if the clause contains no Vars of + * the current query level and no volatile functions. Such a clause can be + * pulled out and used as a one-time qual in a gating Result node. We keep + * pseudoconstant clauses in the same lists as other RestrictInfos so that + * the regular clause-pushing machinery can assign them to the correct join + * level, but they need to be treated specially for cost and selectivity + * estimates. Note that a pseudoconstant clause can never be an indexqual + * or merge or hash join clause, so it's of no interest to large parts of + * the planner. + * + * When we generate multiple versions of a clause so as to have versions + * that will work after commuting some left joins per outer join identity 3, + * we mark the one with the fewest nullingrels bits with has_clone = true, + * and the rest with is_clone = true. This allows proper filtering of + * these redundant clauses, so that we apply only one version of them. + * + * When join clauses are generated from EquivalenceClasses, there may be + * several equally valid ways to enforce join equivalence, of which we need + * apply only one. We mark clauses of this kind by setting parent_ec to + * point to the generating EquivalenceClass. Multiple clauses with the same + * parent_ec in the same join are redundant. + * + * Most fields are ignored for equality, since they may not be set yet, and + * should be derivable from the clause anyway. + * + * parent_ec, left_ec, right_ec are not printed, lest it lead to infinite + * recursion in plan tree dump. + */ + +typedef struct RestrictInfo +{ + pg_node_attr(no_read, no_query_jumble) + + NodeTag type; + + /* the represented clause of WHERE or JOIN */ + Expr *clause; + + /* true if clause was pushed down in level */ + bool is_pushed_down; + + /* see comment above */ + bool can_join pg_node_attr(equal_ignore); + + /* see comment above */ + bool pseudoconstant pg_node_attr(equal_ignore); + + /* see comment above */ + bool has_clone; + bool is_clone; + + /* true if known to contain no leaked Vars */ + bool leakproof pg_node_attr(equal_ignore); + + /* indicates if clause contains any volatile functions */ + VolatileFunctionStatus has_volatile pg_node_attr(equal_ignore); + + /* see comment above */ + Index security_level; + + /* number of base rels in clause_relids */ + int num_base_rels pg_node_attr(equal_ignore); + + /* The relids (varnos+varnullingrels) actually referenced in the clause: */ + Relids clause_relids pg_node_attr(equal_ignore); + + /* The set of relids required to evaluate the clause: */ + Relids required_relids; + + /* Relids above which we cannot evaluate the clause (see comment above) */ + Relids incompatible_relids; + + /* If an outer-join clause, the outer-side relations, else NULL: */ + Relids outer_relids; + + /* + * Relids in the left/right side of the clause. These fields are set for + * any binary opclause. + */ + Relids left_relids pg_node_attr(equal_ignore); + Relids right_relids pg_node_attr(equal_ignore); + + /* + * Modified clause with RestrictInfos. This field is NULL unless clause + * is an OR clause. + */ + Expr *orclause pg_node_attr(equal_ignore); + + /*---------- + * Serial number of this RestrictInfo. This is unique within the current + * PlannerInfo context, with a few critical exceptions: + * 1. When we generate multiple clones of the same qual condition to + * cope with outer join identity 3, all the clones get the same serial + * number. This reflects that we only want to apply one of them in any + * given plan. + * 2. If we manufacture a commuted version of a qual to use as an index + * condition, it copies the original's rinfo_serial, since it is in + * practice the same condition. + * 3. RestrictInfos made for a child relation copy their parent's + * rinfo_serial. Likewise, when an EquivalenceClass makes a derived + * equality clause for a child relation, it copies the rinfo_serial of + * the matching equality clause for the parent. This allows detection + * of redundant pushed-down equality clauses. + *---------- + */ + int rinfo_serial; + + /* + * Generating EquivalenceClass. This field is NULL unless clause is + * potentially redundant. + */ + EquivalenceClass *parent_ec pg_node_attr(copy_as_scalar, equal_ignore, read_write_ignore); + + /* + * cache space for cost and selectivity + */ + + /* eval cost of clause; -1 if not yet set */ + QualCost eval_cost pg_node_attr(equal_ignore); + + /* selectivity for "normal" (JOIN_INNER) semantics; -1 if not yet set */ + Selectivity norm_selec pg_node_attr(equal_ignore); + /* selectivity for outer join semantics; -1 if not yet set */ + Selectivity outer_selec pg_node_attr(equal_ignore); + + /* + * opfamilies containing clause operator; valid if clause is + * mergejoinable, else NIL + */ + List *mergeopfamilies pg_node_attr(equal_ignore); + + /* + * cache space for mergeclause processing; NULL if not yet set + */ + + /* EquivalenceClass containing lefthand */ + EquivalenceClass *left_ec pg_node_attr(copy_as_scalar, equal_ignore, read_write_ignore); + /* EquivalenceClass containing righthand */ + EquivalenceClass *right_ec pg_node_attr(copy_as_scalar, equal_ignore, read_write_ignore); + /* EquivalenceMember for lefthand */ + EquivalenceMember *left_em pg_node_attr(copy_as_scalar, equal_ignore); + /* EquivalenceMember for righthand */ + EquivalenceMember *right_em pg_node_attr(copy_as_scalar, equal_ignore); + + /* + * List of MergeScanSelCache structs. Those aren't Nodes, so hard to + * copy; instead replace with NIL. That has the effect that copying will + * just reset the cache. Likewise, can't compare or print them. + */ + List *scansel_cache pg_node_attr(copy_as(NIL), equal_ignore, read_write_ignore); + + /* + * transient workspace for use while considering a specific join path; T = + * outer var on left, F = on right + */ + bool outer_is_left pg_node_attr(equal_ignore); + + /* + * copy of clause operator; valid if clause is hashjoinable, else + * InvalidOid + */ + Oid hashjoinoperator pg_node_attr(equal_ignore); + + /* + * cache space for hashclause processing; -1 if not yet set + */ + /* avg bucketsize of left side */ + Selectivity left_bucketsize pg_node_attr(equal_ignore); + /* avg bucketsize of right side */ + Selectivity right_bucketsize pg_node_attr(equal_ignore); + /* left side's most common val's freq */ + Selectivity left_mcvfreq pg_node_attr(equal_ignore); + /* right side's most common val's freq */ + Selectivity right_mcvfreq pg_node_attr(equal_ignore); + + /* hash equality operators used for memoize nodes, else InvalidOid */ + Oid left_hasheqoperator pg_node_attr(equal_ignore); + Oid right_hasheqoperator pg_node_attr(equal_ignore); +} RestrictInfo; + +/* + * This macro embodies the correct way to test whether a RestrictInfo is + * "pushed down" to a given outer join, that is, should be treated as a filter + * clause rather than a join clause at that outer join. This is certainly so + * if is_pushed_down is true; but examining that is not sufficient anymore, + * because outer-join clauses will get pushed down to lower outer joins when + * we generate a path for the lower outer join that is parameterized by the + * LHS of the upper one. We can detect such a clause by noting that its + * required_relids exceed the scope of the join. + */ +#define RINFO_IS_PUSHED_DOWN(rinfo, joinrelids) \ + ((rinfo)->is_pushed_down || \ + !bms_is_subset((rinfo)->required_relids, joinrelids)) + +/* + * Since mergejoinscansel() is a relatively expensive function, and would + * otherwise be invoked many times while planning a large join tree, + * we go out of our way to cache its results. Each mergejoinable + * RestrictInfo carries a list of the specific sort orderings that have + * been considered for use with it, and the resulting selectivities. + */ +typedef struct MergeScanSelCache +{ + /* Ordering details (cache lookup key) */ + Oid opfamily; /* btree opfamily defining the ordering */ + Oid collation; /* collation for the ordering */ + int strategy; /* sort direction (ASC or DESC) */ + bool nulls_first; /* do NULLs come before normal values? */ + /* Results */ + Selectivity leftstartsel; /* first-join fraction for clause left side */ + Selectivity leftendsel; /* last-join fraction for clause left side */ + Selectivity rightstartsel; /* first-join fraction for clause right side */ + Selectivity rightendsel; /* last-join fraction for clause right side */ +} MergeScanSelCache; + +/* + * Placeholder node for an expression to be evaluated below the top level + * of a plan tree. This is used during planning to represent the contained + * expression. At the end of the planning process it is replaced by either + * the contained expression or a Var referring to a lower-level evaluation of + * the contained expression. Generally the evaluation occurs below an outer + * join, and Var references above the outer join might thereby yield NULL + * instead of the expression value. + * + * phrels and phlevelsup correspond to the varno/varlevelsup fields of a + * plain Var, except that phrels has to be a relid set since the evaluation + * level of a PlaceHolderVar might be a join rather than a base relation. + * Likewise, phnullingrels corresponds to varnullingrels. + * + * Although the planner treats this as an expression node type, it is not + * recognized by the parser or executor, so we declare it here rather than + * in primnodes.h. + * + * We intentionally do not compare phexpr. Two PlaceHolderVars with the + * same ID and levelsup should be considered equal even if the contained + * expressions have managed to mutate to different states. This will + * happen during final plan construction when there are nested PHVs, since + * the inner PHV will get replaced by a Param in some copies of the outer + * PHV. Another way in which it can happen is that initplan sublinks + * could get replaced by differently-numbered Params when sublink folding + * is done. (The end result of such a situation would be some + * unreferenced initplans, which is annoying but not really a problem.) + * On the same reasoning, there is no need to examine phrels. But we do + * need to compare phnullingrels, as that represents effects that are + * external to the original value of the PHV. + */ + +typedef struct PlaceHolderVar +{ + pg_node_attr(no_query_jumble) + + Expr xpr; + + /* the represented expression */ + Expr *phexpr pg_node_attr(equal_ignore); + + /* base+OJ relids syntactically within expr src */ + Relids phrels pg_node_attr(equal_ignore); + + /* RT indexes of outer joins that can null PHV's value */ + Relids phnullingrels; + + /* ID for PHV (unique within planner run) */ + Index phid; + + /* > 0 if PHV belongs to outer query */ + Index phlevelsup; +} PlaceHolderVar; + +/* + * "Special join" info. + * + * One-sided outer joins constrain the order of joining partially but not + * completely. We flatten such joins into the planner's top-level list of + * relations to join, but record information about each outer join in a + * SpecialJoinInfo struct. These structs are kept in the PlannerInfo node's + * join_info_list. + * + * Similarly, semijoins and antijoins created by flattening IN (subselect) + * and EXISTS(subselect) clauses create partial constraints on join order. + * These are likewise recorded in SpecialJoinInfo structs. + * + * We make SpecialJoinInfos for FULL JOINs even though there is no flexibility + * of planning for them, because this simplifies make_join_rel()'s API. + * + * min_lefthand and min_righthand are the sets of base+OJ relids that must be + * available on each side when performing the special join. + * It is not valid for either min_lefthand or min_righthand to be empty sets; + * if they were, this would break the logic that enforces join order. + * + * syn_lefthand and syn_righthand are the sets of base+OJ relids that are + * syntactically below this special join. (These are needed to help compute + * min_lefthand and min_righthand for higher joins.) + * + * jointype is never JOIN_RIGHT; a RIGHT JOIN is handled by switching + * the inputs to make it a LEFT JOIN. It's never JOIN_RIGHT_ANTI either. + * So the allowed values of jointype in a join_info_list member are only + * LEFT, FULL, SEMI, or ANTI. + * + * ojrelid is the RT index of the join RTE representing this outer join, + * if there is one. It is zero when jointype is INNER or SEMI, and can be + * zero for jointype ANTI (if the join was transformed from a SEMI join). + * One use for this field is that when constructing the output targetlist of a + * join relation that implements this OJ, we add ojrelid to the varnullingrels + * and phnullingrels fields of nullable (RHS) output columns, so that the + * output Vars and PlaceHolderVars correctly reflect the nulling that has + * potentially happened to them. + * + * commute_above_l is filled with the relids of syntactically-higher outer + * joins that have been found to commute with this one per outer join identity + * 3 (see optimizer/README), when this join is in the LHS of the upper join + * (so, this is the lower join in the first form of the identity). + * + * commute_above_r is filled with the relids of syntactically-higher outer + * joins that have been found to commute with this one per outer join identity + * 3, when this join is in the RHS of the upper join (so, this is the lower + * join in the second form of the identity). + * + * commute_below_l is filled with the relids of syntactically-lower outer + * joins that have been found to commute with this one per outer join identity + * 3 and are in the LHS of this join (so, this is the upper join in the first + * form of the identity). + * + * commute_below_r is filled with the relids of syntactically-lower outer + * joins that have been found to commute with this one per outer join identity + * 3 and are in the RHS of this join (so, this is the upper join in the second + * form of the identity). + * + * lhs_strict is true if the special join's condition cannot succeed when the + * LHS variables are all NULL (this means that an outer join can commute with + * upper-level outer joins even if it appears in their RHS). We don't bother + * to set lhs_strict for FULL JOINs, however. + * + * For a semijoin, we also extract the join operators and their RHS arguments + * and set semi_operators, semi_rhs_exprs, semi_can_btree, and semi_can_hash. + * This is done in support of possibly unique-ifying the RHS, so we don't + * bother unless at least one of semi_can_btree and semi_can_hash can be set + * true. (You might expect that this information would be computed during + * join planning; but it's helpful to have it available during planning of + * parameterized table scans, so we store it in the SpecialJoinInfo structs.) + * + * For purposes of join selectivity estimation, we create transient + * SpecialJoinInfo structures for regular inner joins; so it is possible + * to have jointype == JOIN_INNER in such a structure, even though this is + * not allowed within join_info_list. We also create transient + * SpecialJoinInfos with jointype == JOIN_INNER for outer joins, since for + * cost estimation purposes it is sometimes useful to know the join size under + * plain innerjoin semantics. Note that lhs_strict and the semi_xxx fields + * are not set meaningfully within such structs. + */ +#ifndef HAVE_SPECIALJOININFO_TYPEDEF +typedef struct SpecialJoinInfo SpecialJoinInfo; +#define HAVE_SPECIALJOININFO_TYPEDEF 1 +#endif + +struct SpecialJoinInfo +{ + pg_node_attr(no_read, no_query_jumble) + + NodeTag type; + Relids min_lefthand; /* base+OJ relids in minimum LHS for join */ + Relids min_righthand; /* base+OJ relids in minimum RHS for join */ + Relids syn_lefthand; /* base+OJ relids syntactically within LHS */ + Relids syn_righthand; /* base+OJ relids syntactically within RHS */ + JoinType jointype; /* always INNER, LEFT, FULL, SEMI, or ANTI */ + Index ojrelid; /* outer join's RT index; 0 if none */ + Relids commute_above_l; /* commuting OJs above this one, if LHS */ + Relids commute_above_r; /* commuting OJs above this one, if RHS */ + Relids commute_below_l; /* commuting OJs in this one's LHS */ + Relids commute_below_r; /* commuting OJs in this one's RHS */ + bool lhs_strict; /* joinclause is strict for some LHS rel */ + /* Remaining fields are set only for JOIN_SEMI jointype: */ + bool semi_can_btree; /* true if semi_operators are all btree */ + bool semi_can_hash; /* true if semi_operators are all hash */ + List *semi_operators; /* OIDs of equality join operators */ + List *semi_rhs_exprs; /* righthand-side expressions of these ops */ +}; + +/* + * Transient outer-join clause info. + * + * We set aside every outer join ON clause that looks mergejoinable, + * and process it specially at the end of qual distribution. + */ +typedef struct OuterJoinClauseInfo +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + RestrictInfo *rinfo; /* a mergejoinable outer-join clause */ + SpecialJoinInfo *sjinfo; /* the outer join's SpecialJoinInfo */ +} OuterJoinClauseInfo; + +/* + * Append-relation info. + * + * When we expand an inheritable table or a UNION-ALL subselect into an + * "append relation" (essentially, a list of child RTEs), we build an + * AppendRelInfo for each child RTE. The list of AppendRelInfos indicates + * which child RTEs must be included when expanding the parent, and each node + * carries information needed to translate between columns of the parent and + * columns of the child. + * + * These structs are kept in the PlannerInfo node's append_rel_list, with + * append_rel_array[] providing a convenient lookup method for the struct + * associated with a particular child relid (there can be only one, though + * parent rels may have many entries in append_rel_list). + * + * Note: after completion of the planner prep phase, any given RTE is an + * append parent having entries in append_rel_list if and only if its + * "inh" flag is set. We clear "inh" for plain tables that turn out not + * to have inheritance children, and (in an abuse of the original meaning + * of the flag) we set "inh" for subquery RTEs that turn out to be + * flattenable UNION ALL queries. This lets us avoid useless searches + * of append_rel_list. + * + * Note: the data structure assumes that append-rel members are single + * baserels. This is OK for inheritance, but it prevents us from pulling + * up a UNION ALL member subquery if it contains a join. While that could + * be fixed with a more complex data structure, at present there's not much + * point because no improvement in the plan could result. + */ + +typedef struct AppendRelInfo +{ + pg_node_attr(no_query_jumble) + + NodeTag type; + + /* + * These fields uniquely identify this append relationship. There can be + * (in fact, always should be) multiple AppendRelInfos for the same + * parent_relid, but never more than one per child_relid, since a given + * RTE cannot be a child of more than one append parent. + */ + Index parent_relid; /* RT index of append parent rel */ + Index child_relid; /* RT index of append child rel */ + + /* + * For an inheritance appendrel, the parent and child are both regular + * relations, and we store their rowtype OIDs here for use in translating + * whole-row Vars. For a UNION-ALL appendrel, the parent and child are + * both subqueries with no named rowtype, and we store InvalidOid here. + */ + Oid parent_reltype; /* OID of parent's composite type */ + Oid child_reltype; /* OID of child's composite type */ + + /* + * The N'th element of this list is a Var or expression representing the + * child column corresponding to the N'th column of the parent. This is + * used to translate Vars referencing the parent rel into references to + * the child. A list element is NULL if it corresponds to a dropped + * column of the parent (this is only possible for inheritance cases, not + * UNION ALL). The list elements are always simple Vars for inheritance + * cases, but can be arbitrary expressions in UNION ALL cases. + * + * Notice we only store entries for user columns (attno > 0). Whole-row + * Vars are special-cased, and system columns (attno < 0) need no special + * translation since their attnos are the same for all tables. + * + * Caution: the Vars have varlevelsup = 0. Be careful to adjust as needed + * when copying into a subquery. + */ + List *translated_vars; /* Expressions in the child's Vars */ + + /* + * This array simplifies translations in the reverse direction, from + * child's column numbers to parent's. The entry at [ccolno - 1] is the + * 1-based parent column number for child column ccolno, or zero if that + * child column is dropped or doesn't exist in the parent. + */ + int num_child_cols; /* length of array */ + AttrNumber *parent_colnos pg_node_attr(array_size(num_child_cols)); + + /* + * We store the parent table's OID here for inheritance, or InvalidOid for + * UNION ALL. This is only needed to help in generating error messages if + * an attempt is made to reference a dropped parent column. + */ + Oid parent_reloid; /* OID of parent relation */ +} AppendRelInfo; + +/* + * Information about a row-identity "resjunk" column in UPDATE/DELETE/MERGE. + * + * In partitioned UPDATE/DELETE/MERGE it's important for child partitions to + * share row-identity columns whenever possible, so as not to chew up too many + * targetlist columns. We use these structs to track which identity columns + * have been requested. In the finished plan, each of these will give rise + * to one resjunk entry in the targetlist of the ModifyTable's subplan node. + * + * All the Vars stored in RowIdentityVarInfos must have varno ROWID_VAR, for + * convenience of detecting duplicate requests. We'll replace that, in the + * final plan, with the varno of the generating rel. + * + * Outside this list, a Var with varno ROWID_VAR and varattno k is a reference + * to the k-th element of the row_identity_vars list (k counting from 1). + * We add such a reference to root->processed_tlist when creating the entry, + * and it propagates into the plan tree from there. + */ +typedef struct RowIdentityVarInfo +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + + Var *rowidvar; /* Var to be evaluated (but varno=ROWID_VAR) */ + int32 rowidwidth; /* estimated average width */ + char *rowidname; /* name of the resjunk column */ + Relids rowidrels; /* RTE indexes of target rels using this */ +} RowIdentityVarInfo; + +/* + * For each distinct placeholder expression generated during planning, we + * store a PlaceHolderInfo node in the PlannerInfo node's placeholder_list. + * This stores info that is needed centrally rather than in each copy of the + * PlaceHolderVar. The phid fields identify which PlaceHolderInfo goes with + * each PlaceHolderVar. Note that phid is unique throughout a planner run, + * not just within a query level --- this is so that we need not reassign ID's + * when pulling a subquery into its parent. + * + * The idea is to evaluate the expression at (only) the ph_eval_at join level, + * then allow it to bubble up like a Var until the ph_needed join level. + * ph_needed has the same definition as attr_needed for a regular Var. + * + * The PlaceHolderVar's expression might contain LATERAL references to vars + * coming from outside its syntactic scope. If so, those rels are *not* + * included in ph_eval_at, but they are recorded in ph_lateral. + * + * Notice that when ph_eval_at is a join rather than a single baserel, the + * PlaceHolderInfo may create constraints on join order: the ph_eval_at join + * has to be formed below any outer joins that should null the PlaceHolderVar. + * + * We create a PlaceHolderInfo only after determining that the PlaceHolderVar + * is actually referenced in the plan tree, so that unreferenced placeholders + * don't result in unnecessary constraints on join order. + */ + +typedef struct PlaceHolderInfo +{ + pg_node_attr(no_read, no_query_jumble) + + NodeTag type; + + /* ID for PH (unique within planner run) */ + Index phid; + + /* + * copy of PlaceHolderVar tree (should be redundant for comparison, could + * be ignored) + */ + PlaceHolderVar *ph_var; + + /* lowest level we can evaluate value at */ + Relids ph_eval_at; + + /* relids of contained lateral refs, if any */ + Relids ph_lateral; + + /* highest level the value is needed at */ + Relids ph_needed; + + /* estimated attribute width */ + int32 ph_width; +} PlaceHolderInfo; + +/* + * This struct describes one potentially index-optimizable MIN/MAX aggregate + * function. MinMaxAggPath contains a list of these, and if we accept that + * path, the list is stored into root->minmax_aggs for use during setrefs.c. + */ +typedef struct MinMaxAggInfo +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + + /* pg_proc Oid of the aggregate */ + Oid aggfnoid; + + /* Oid of its sort operator */ + Oid aggsortop; + + /* expression we are aggregating on */ + Expr *target; + + /* + * modified "root" for planning the subquery; not printed, too large, not + * interesting enough + */ + PlannerInfo *subroot pg_node_attr(read_write_ignore); + + /* access path for subquery */ + Path *path; + + /* estimated cost to fetch first row */ + Cost pathcost; + + /* param for subplan's output */ + Param *param; +} MinMaxAggInfo; + +/* + * At runtime, PARAM_EXEC slots are used to pass values around from one plan + * node to another. They can be used to pass values down into subqueries (for + * outer references in subqueries), or up out of subqueries (for the results + * of a subplan), or from a NestLoop plan node into its inner relation (when + * the inner scan is parameterized with values from the outer relation). + * The planner is responsible for assigning nonconflicting PARAM_EXEC IDs to + * the PARAM_EXEC Params it generates. + * + * Outer references are managed via root->plan_params, which is a list of + * PlannerParamItems. While planning a subquery, each parent query level's + * plan_params contains the values required from it by the current subquery. + * During create_plan(), we use plan_params to track values that must be + * passed from outer to inner sides of NestLoop plan nodes. + * + * The item a PlannerParamItem represents can be one of three kinds: + * + * A Var: the slot represents a variable of this level that must be passed + * down because subqueries have outer references to it, or must be passed + * from a NestLoop node to its inner scan. The varlevelsup value in the Var + * will always be zero. + * + * A PlaceHolderVar: this works much like the Var case, except that the + * entry is a PlaceHolderVar node with a contained expression. The PHV + * will have phlevelsup = 0, and the contained expression is adjusted + * to match in level. + * + * An Aggref (with an expression tree representing its argument): the slot + * represents an aggregate expression that is an outer reference for some + * subquery. The Aggref itself has agglevelsup = 0, and its argument tree + * is adjusted to match in level. + * + * Note: we detect duplicate Var and PlaceHolderVar parameters and coalesce + * them into one slot, but we do not bother to do that for Aggrefs. + * The scope of duplicate-elimination only extends across the set of + * parameters passed from one query level into a single subquery, or for + * nestloop parameters across the set of nestloop parameters used in a single + * query level. So there is no possibility of a PARAM_EXEC slot being used + * for conflicting purposes. + * + * In addition, PARAM_EXEC slots are assigned for Params representing outputs + * from subplans (values that are setParam items for those subplans). These + * IDs need not be tracked via PlannerParamItems, since we do not need any + * duplicate-elimination nor later processing of the represented expressions. + * Instead, we just record the assignment of the slot number by appending to + * root->glob->paramExecTypes. + */ +typedef struct PlannerParamItem +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + + Node *item; /* the Var, PlaceHolderVar, or Aggref */ + int paramId; /* its assigned PARAM_EXEC slot number */ +} PlannerParamItem; + +/* + * When making cost estimates for a SEMI/ANTI/inner_unique join, there are + * some correction factors that are needed in both nestloop and hash joins + * to account for the fact that the executor can stop scanning inner rows + * as soon as it finds a match to the current outer row. These numbers + * depend only on the selected outer and inner join relations, not on the + * particular paths used for them, so it's worthwhile to calculate them + * just once per relation pair not once per considered path. This struct + * is filled by compute_semi_anti_join_factors and must be passed along + * to the join cost estimation functions. + * + * outer_match_frac is the fraction of the outer tuples that are + * expected to have at least one match. + * match_count is the average number of matches expected for + * outer tuples that have at least one match. + */ +typedef struct SemiAntiJoinFactors +{ + Selectivity outer_match_frac; + Selectivity match_count; +} SemiAntiJoinFactors; + +/* + * Struct for extra information passed to subroutines of add_paths_to_joinrel + * + * restrictlist contains all of the RestrictInfo nodes for restriction + * clauses that apply to this join + * mergeclause_list is a list of RestrictInfo nodes for available + * mergejoin clauses in this join + * inner_unique is true if each outer tuple provably matches no more + * than one inner tuple + * sjinfo is extra info about special joins for selectivity estimation + * semifactors is as shown above (only valid for SEMI/ANTI/inner_unique joins) + * param_source_rels are OK targets for parameterization of result paths + */ +typedef struct JoinPathExtraData +{ + List *restrictlist; + List *mergeclause_list; + bool inner_unique; + SpecialJoinInfo *sjinfo; + SemiAntiJoinFactors semifactors; + Relids param_source_rels; +} JoinPathExtraData; + +/* + * Various flags indicating what kinds of grouping are possible. + * + * GROUPING_CAN_USE_SORT should be set if it's possible to perform + * sort-based implementations of grouping. When grouping sets are in use, + * this will be true if sorting is potentially usable for any of the grouping + * sets, even if it's not usable for all of them. + * + * GROUPING_CAN_USE_HASH should be set if it's possible to perform + * hash-based implementations of grouping. + * + * GROUPING_CAN_PARTIAL_AGG should be set if the aggregation is of a type + * for which we support partial aggregation (not, for example, grouping sets). + * It says nothing about parallel-safety or the availability of suitable paths. + */ +#define GROUPING_CAN_USE_SORT 0x0001 +#define GROUPING_CAN_USE_HASH 0x0002 +#define GROUPING_CAN_PARTIAL_AGG 0x0004 + +/* + * What kind of partitionwise aggregation is in use? + * + * PARTITIONWISE_AGGREGATE_NONE: Not used. + * + * PARTITIONWISE_AGGREGATE_FULL: Aggregate each partition separately, and + * append the results. + * + * PARTITIONWISE_AGGREGATE_PARTIAL: Partially aggregate each partition + * separately, append the results, and then finalize aggregation. + */ +typedef enum +{ + PARTITIONWISE_AGGREGATE_NONE, + PARTITIONWISE_AGGREGATE_FULL, + PARTITIONWISE_AGGREGATE_PARTIAL +} PartitionwiseAggregateType; + +/* + * Struct for extra information passed to subroutines of create_grouping_paths + * + * flags indicating what kinds of grouping are possible. + * partial_costs_set is true if the agg_partial_costs and agg_final_costs + * have been initialized. + * agg_partial_costs gives partial aggregation costs. + * agg_final_costs gives finalization costs. + * target_parallel_safe is true if target is parallel safe. + * havingQual gives list of quals to be applied after aggregation. + * targetList gives list of columns to be projected. + * patype is the type of partitionwise aggregation that is being performed. + */ +typedef struct +{ + /* Data which remains constant once set. */ + int flags; + bool partial_costs_set; + AggClauseCosts agg_partial_costs; + AggClauseCosts agg_final_costs; + + /* Data which may differ across partitions. */ + bool target_parallel_safe; + Node *havingQual; + List *targetList; + PartitionwiseAggregateType patype; +} GroupPathExtraData; + +/* + * Struct for extra information passed to subroutines of grouping_planner + * + * limit_needed is true if we actually need a Limit plan node. + * limit_tuples is an estimated bound on the number of output tuples, + * or -1 if no LIMIT or couldn't estimate. + * count_est and offset_est are the estimated values of the LIMIT and OFFSET + * expressions computed by preprocess_limit() (see comments for + * preprocess_limit() for more information). + */ +typedef struct +{ + bool limit_needed; + Cardinality limit_tuples; + int64 count_est; + int64 offset_est; +} FinalPathExtraData; + +/* + * For speed reasons, cost estimation for join paths is performed in two + * phases: the first phase tries to quickly derive a lower bound for the + * join cost, and then we check if that's sufficient to reject the path. + * If not, we come back for a more refined cost estimate. The first phase + * fills a JoinCostWorkspace struct with its preliminary cost estimates + * and possibly additional intermediate values. The second phase takes + * these values as inputs to avoid repeating work. + * + * (Ideally we'd declare this in cost.h, but it's also needed in pathnode.h, + * so seems best to put it here.) + */ +typedef struct JoinCostWorkspace +{ + /* Preliminary cost estimates --- must not be larger than final ones! */ + Cost startup_cost; /* cost expended before fetching any tuples */ + Cost total_cost; /* total cost (assuming all tuples fetched) */ + + /* Fields below here should be treated as private to costsize.c */ + Cost run_cost; /* non-startup cost components */ + + /* private for cost_nestloop code */ + Cost inner_run_cost; /* also used by cost_mergejoin code */ + Cost inner_rescan_run_cost; + + /* private for cost_mergejoin code */ + Cardinality outer_rows; + Cardinality inner_rows; + Cardinality outer_skip_rows; + Cardinality inner_skip_rows; + + /* private for cost_hashjoin code */ + int numbuckets; + int numbatches; + Cardinality inner_rows_total; +} JoinCostWorkspace; + +/* + * AggInfo holds information about an aggregate that needs to be computed. + * Multiple Aggrefs in a query can refer to the same AggInfo by having the + * same 'aggno' value, so that the aggregate is computed only once. + */ +typedef struct AggInfo +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + + /* + * List of Aggref exprs that this state value is for. + * + * There will always be at least one, but there can be multiple identical + * Aggref's sharing the same per-agg. + */ + List *aggrefs; + + /* Transition state number for this aggregate */ + int transno; + + /* + * "shareable" is false if this agg cannot share state values with other + * aggregates because the final function is read-write. + */ + bool shareable; + + /* Oid of the final function, or InvalidOid if none */ + Oid finalfn_oid; +} AggInfo; + +/* + * AggTransInfo holds information about transition state that is used by one + * or more aggregates in the query. Multiple aggregates can share the same + * transition state, if they have the same inputs and the same transition + * function. Aggrefs that share the same transition info have the same + * 'aggtransno' value. + */ +typedef struct AggTransInfo +{ + pg_node_attr(no_copy_equal, no_read, no_query_jumble) + + NodeTag type; + + /* Inputs for this transition state */ + List *args; + Expr *aggfilter; + + /* Oid of the state transition function */ + Oid transfn_oid; + + /* Oid of the serialization function, or InvalidOid if none */ + Oid serialfn_oid; + + /* Oid of the deserialization function, or InvalidOid if none */ + Oid deserialfn_oid; + + /* Oid of the combine function, or InvalidOid if none */ + Oid combinefn_oid; + + /* Oid of state value's datatype */ + Oid aggtranstype; + + /* Additional data about transtype */ + int32 aggtranstypmod; + int transtypeLen; + bool transtypeByVal; + + /* Space-consumption estimate */ + int32 aggtransspace; + + /* Initial value from pg_aggregate entry */ + Datum initValue pg_node_attr(read_write_ignore); + bool initValueIsNull; +} AggTransInfo; + +#endif /* PATHNODES_H */ |