| /*------------------------------------------------------------------------- |
| * |
| * pathnodes.h |
| * Definitions for planner's internal data structures, especially Paths. |
| * |
| * |
| * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group |
| * Portions Copyright (c) 1994, Regents of the University of California |
| * |
| * src/include/nodes/pathnodes.h |
| * |
| *------------------------------------------------------------------------- |
| */ |
| #ifndef PATHNODES_H |
| #define PATHNODES_H |
| |
| #include "access/sdir.h" |
| #include "lib/stringinfo.h" |
| #include "nodes/params.h" |
| #include "nodes/parsenodes.h" |
| #include "storage/block.h" |
| |
| |
| /* |
| * Relids |
| * Set of relation identifiers (indexes into the rangetable). |
| */ |
| typedef Bitmapset *Relids; |
| |
| /* |
| * When looking for a "cheapest path", this enum specifies whether we want |
| * cheapest startup cost or cheapest total cost. |
| */ |
| typedef enum CostSelector |
| { |
| STARTUP_COST, TOTAL_COST |
| } CostSelector; |
| |
| /* |
| * The cost estimate produced by cost_qual_eval() includes both a one-time |
| * (startup) cost, and a per-tuple cost. |
| */ |
| typedef struct QualCost |
| { |
| Cost startup; /* one-time cost */ |
| Cost per_tuple; /* per-evaluation cost */ |
| } QualCost; |
| |
| /* |
| * Costing aggregate function execution requires these statistics about |
| * the aggregates to be executed by a given Agg node. Note that the costs |
| * include the execution costs of the aggregates' argument expressions as |
| * well as the aggregate functions themselves. Also, the fields must be |
| * defined so that initializing the struct to zeroes with memset is correct. |
| */ |
| typedef struct AggClauseCosts |
| { |
| int numAggs; /* total number of aggregate functions */ |
| int numOrderedAggs; /* number w/ DISTINCT/ORDER BY/WITHIN GROUP */ |
| bool hasNonPartial; /* does any agg not support partial mode? */ |
| bool hasNonSerial; /* is any partial agg non-serializable? */ |
| QualCost transCost; /* total per-input-row execution costs */ |
| QualCost finalCost; /* total per-aggregated-row costs */ |
| Size transitionSpace; /* space for pass-by-ref transition data */ |
| } AggClauseCosts; |
| |
| /* |
| * This enum identifies the different types of "upper" (post-scan/join) |
| * relations that we might deal with during planning. |
| */ |
| typedef enum UpperRelationKind |
| { |
| UPPERREL_SETOP, /* result of UNION/INTERSECT/EXCEPT, if any */ |
| UPPERREL_PARTIAL_GROUP_AGG, /* result of partial grouping/aggregation, if |
| * any */ |
| UPPERREL_GROUP_AGG, /* result of grouping/aggregation, if any */ |
| UPPERREL_WINDOW, /* result of window functions, if any */ |
| UPPERREL_DISTINCT, /* result of "SELECT DISTINCT", if any */ |
| UPPERREL_ORDERED, /* result of ORDER BY, if any */ |
| UPPERREL_SHORTESTPATH, /* result of shortestpath */ |
| UPPERREL_DIJKSTRA, /* result of dijkstra */ |
| UPPERREL_FINAL /* result of any remaining top-level actions */ |
| /* NB: UPPERREL_FINAL must be last enum entry; it's used to size arrays */ |
| } UpperRelationKind; |
| |
| /* |
| * This enum identifies which type of relation is being planned through the |
| * inheritance planner. INHKIND_NONE indicates the inheritance planner |
| * was not used. |
| */ |
| typedef enum InheritanceKind |
| { |
| INHKIND_NONE, |
| INHKIND_INHERITED, |
| INHKIND_PARTITIONED |
| } InheritanceKind; |
| |
| /*---------- |
| * PlannerGlobal |
| * Global information for planning/optimization |
| * |
| * PlannerGlobal holds state for an entire planner invocation; this state |
| * is shared across all levels of sub-Queries that exist in the command being |
| * planned. |
| *---------- |
| */ |
| typedef struct PlannerGlobal |
| { |
| NodeTag type; |
| |
| ParamListInfo boundParams; /* Param values provided to planner() */ |
| |
| List *subplans; /* Plans for SubPlan nodes */ |
| |
| List *subroots; /* PlannerInfos for SubPlan nodes */ |
| |
| Bitmapset *rewindPlanIDs; /* indices of subplans that require REWIND */ |
| |
| List *finalrtable; /* "flat" rangetable for executor */ |
| |
| List *finalrowmarks; /* "flat" list of PlanRowMarks */ |
| |
| List *resultRelations; /* "flat" list of integer RT indexes */ |
| |
| List *rootResultRelations; /* "flat" list of integer RT indexes */ |
| |
| List *appendRelations; /* "flat" list of AppendRelInfos */ |
| |
| List *relationOids; /* OIDs of relations the plan depends on */ |
| |
| List *invalItems; /* other dependencies, as PlanInvalItems */ |
| |
| List *paramExecTypes; /* type OIDs for PARAM_EXEC Params */ |
| |
| Index lastPHId; /* highest PlaceHolderVar ID assigned */ |
| |
| Index lastRowMarkId; /* highest PlanRowMark ID assigned */ |
| |
| int lastPlanNodeId; /* highest plan node ID assigned */ |
| |
| bool transientPlan; /* redo plan when TransactionXmin changes? */ |
| |
| bool dependsOnRole; /* is plan specific to current role? */ |
| |
| bool parallelModeOK; /* parallel mode potentially OK? */ |
| |
| bool parallelModeNeeded; /* parallel mode actually required? */ |
| |
| char maxParallelHazard; /* worst PROPARALLEL hazard level */ |
| |
| PartitionDirectory partition_directory; /* partition descriptors */ |
| } PlannerGlobal; |
| |
| /* macro for fetching the Plan associated with a SubPlan node */ |
| #define planner_subplan_get_plan(root, subplan) \ |
| ((Plan *) list_nth((root)->glob->subplans, (subplan)->plan_id - 1)) |
| |
| |
| /*---------- |
| * PlannerInfo |
| * Per-query information for planning/optimization |
| * |
| * This struct is conventionally called "root" in all the planner routines. |
| * It holds links to all of the planner's working state, in addition to the |
| * original Query. Note that at present the planner extensively modifies |
| * the passed-in Query data structure; someday that should stop. |
| * |
| * For reasons explained in optimizer/optimizer.h, we define the typedef |
| * either here or in that header, whichever is read first. |
| *---------- |
| */ |
| #ifndef HAVE_PLANNERINFO_TYPEDEF |
| typedef struct PlannerInfo PlannerInfo; |
| #define HAVE_PLANNERINFO_TYPEDEF 1 |
| #endif |
| |
| struct PlannerInfo |
| { |
| NodeTag type; |
| |
| Query *parse; /* the Query being planned */ |
| |
| PlannerGlobal *glob; /* global info for current planner run */ |
| |
| Index query_level; /* 1 at the outermost Query */ |
| |
| PlannerInfo *parent_root; /* NULL at outermost Query */ |
| |
| /* |
| * plan_params contains the expressions that this query level needs to |
| * make available to a lower query level that is currently being planned. |
| * outer_params contains the paramIds of PARAM_EXEC Params that outer |
| * query levels will make available to this query level. |
| */ |
| List *plan_params; /* list of PlannerParamItems, see below */ |
| Bitmapset *outer_params; |
| |
| /* |
| * simple_rel_array holds pointers to "base rels" and "other rels" (see |
| * comments for RelOptInfo for more info). It is indexed by rangetable |
| * index (so entry 0 is always wasted). Entries can be NULL when an RTE |
| * does not correspond to a base relation, such as a join RTE or an |
| * unreferenced view RTE; or if the RelOptInfo hasn't been made yet. |
| */ |
| struct RelOptInfo **simple_rel_array; /* All 1-rel RelOptInfos */ |
| int simple_rel_array_size; /* allocated size of array */ |
| |
| /* |
| * simple_rte_array is the same length as simple_rel_array and holds |
| * pointers to the associated rangetable entries. Using this is a shade |
| * faster than using rt_fetch(), mostly due to fewer indirections. |
| */ |
| RangeTblEntry **simple_rte_array; /* rangetable as an array */ |
| |
| /* |
| * append_rel_array is the same length as the above arrays, and holds |
| * pointers to the corresponding AppendRelInfo entry indexed by |
| * child_relid, or NULL if the rel is not an appendrel child. The array |
| * itself is not allocated if append_rel_list is empty. |
| */ |
| struct AppendRelInfo **append_rel_array; |
| |
| /* |
| * all_baserels is a Relids set of all base relids (but not "other" |
| * relids) in the query; that is, the Relids identifier of the final join |
| * we need to form. This is computed in make_one_rel, just before we |
| * start making Paths. |
| */ |
| Relids all_baserels; |
| |
| /* |
| * nullable_baserels is a Relids set of base relids that are nullable by |
| * some outer join in the jointree; these are rels that are potentially |
| * nullable below the WHERE clause, SELECT targetlist, etc. This is |
| * computed in deconstruct_jointree. |
| */ |
| Relids nullable_baserels; |
| |
| /* |
| * join_rel_list is a list of all join-relation RelOptInfos we have |
| * considered in this planning run. For small problems we just scan the |
| * list to do lookups, but when there are many join relations we build a |
| * hash table for faster lookups. The hash table is present and valid |
| * when join_rel_hash is not NULL. Note that we still maintain the list |
| * even when using the hash table for lookups; this simplifies life for |
| * GEQO. |
| */ |
| List *join_rel_list; /* list of join-relation RelOptInfos */ |
| struct HTAB *join_rel_hash; /* optional hashtable for join relations */ |
| |
| /* |
| * When doing a dynamic-programming-style join search, join_rel_level[k] |
| * is a list of all join-relation RelOptInfos of level k, and |
| * join_cur_level is the current level. New join-relation RelOptInfos are |
| * automatically added to the join_rel_level[join_cur_level] list. |
| * join_rel_level is NULL if not in use. |
| */ |
| List **join_rel_level; /* lists of join-relation RelOptInfos */ |
| int join_cur_level; /* index of list being extended */ |
| |
| List *init_plans; /* init SubPlans for query */ |
| |
| List *cte_plan_ids; /* per-CTE-item list of subplan IDs (or -1 if |
| * no subplan was made for that CTE) */ |
| |
| List *multiexpr_params; /* List of Lists of Params for MULTIEXPR |
| * subquery outputs */ |
| |
| List *eq_classes; /* list of active EquivalenceClasses */ |
| |
| bool ec_merging_done; /* set true once ECs are canonical */ |
| |
| List *canon_pathkeys; /* list of "canonical" PathKeys */ |
| |
| List *left_join_clauses; /* list of RestrictInfos for mergejoinable |
| * outer join clauses w/nonnullable var on |
| * left */ |
| |
| List *right_join_clauses; /* list of RestrictInfos for mergejoinable |
| * outer join clauses w/nonnullable var on |
| * right */ |
| |
| List *full_join_clauses; /* list of RestrictInfos for mergejoinable |
| * full join clauses */ |
| |
| List *join_info_list; /* list of SpecialJoinInfos */ |
| |
| /* |
| * Note: for AppendRelInfos describing partitions of a partitioned table, |
| * we guarantee that partitions that come earlier in the partitioned |
| * table's PartitionDesc will appear earlier in append_rel_list. |
| */ |
| List *append_rel_list; /* list of AppendRelInfos */ |
| |
| List *rowMarks; /* list of PlanRowMarks */ |
| |
| List *placeholder_list; /* list of PlaceHolderInfos */ |
| |
| List *fkey_list; /* list of ForeignKeyOptInfos */ |
| |
| List *query_pathkeys; /* desired pathkeys for query_planner() */ |
| |
| List *group_pathkeys; /* groupClause pathkeys, if any */ |
| List *window_pathkeys; /* pathkeys of bottom window, if any */ |
| List *distinct_pathkeys; /* distinctClause pathkeys, if any */ |
| List *sort_pathkeys; /* sortClause pathkeys, if any */ |
| |
| List *part_schemes; /* Canonicalised partition schemes used in the |
| * query. */ |
| |
| List *initial_rels; /* RelOptInfos we are now trying to join */ |
| |
| /* Use fetch_upper_rel() to get any particular upper rel */ |
| List *upper_rels[UPPERREL_FINAL + 1]; /* upper-rel RelOptInfos */ |
| |
| /* Result tlists chosen by grouping_planner for upper-stage processing */ |
| struct PathTarget *upper_targets[UPPERREL_FINAL + 1]; |
| |
| /* |
| * The fully-processed targetlist is kept here. It differs from |
| * parse->targetList in that (for INSERT and UPDATE) it's been reordered |
| * to match the target table, and defaults have been filled in. Also, |
| * additional resjunk targets may be present. preprocess_targetlist() |
| * does most of this work, but note that more resjunk targets can get |
| * added during appendrel expansion. (Hence, upper_targets mustn't get |
| * set up till after that.) |
| */ |
| List *processed_tlist; |
| |
| /* Fields filled during create_plan() for use in setrefs.c */ |
| AttrNumber *grouping_map; /* for GroupingFunc fixup */ |
| List *minmax_aggs; /* List of MinMaxAggInfos */ |
| |
| MemoryContext planner_cxt; /* context holding PlannerInfo */ |
| |
| double total_table_pages; /* # of pages in all non-dummy tables of |
| * query */ |
| |
| double tuple_fraction; /* tuple_fraction passed to query_planner */ |
| double limit_tuples; /* limit_tuples passed to query_planner */ |
| |
| Index qual_security_level; /* minimum security_level for quals */ |
| /* Note: qual_security_level is zero if there are no securityQuals */ |
| |
| InheritanceKind inhTargetKind; /* indicates if the target relation is an |
| * inheritance child or partition or a |
| * partitioned table */ |
| bool hasJoinRTEs; /* true if any RTEs are RTE_JOIN kind */ |
| bool hasLateralRTEs; /* true if any RTEs are marked LATERAL */ |
| bool hasHavingQual; /* true if havingQual was non-null */ |
| bool hasPseudoConstantQuals; /* true if any RestrictInfo has |
| * pseudoconstant = true */ |
| bool hasRecursion; /* true if planning a recursive WITH item */ |
| bool hasVLEJoinRTE; /* has VLE join or a child node of VLE join */ |
| |
| /* These fields are used only when hasRecursion is true: */ |
| int wt_param_id; /* PARAM_EXEC ID for the work table */ |
| struct Path *non_recursive_path; /* a path for non-recursive term */ |
| |
| /* These fields are workspace for createplan.c */ |
| Relids curOuterRels; /* outer rels above current node */ |
| List *curOuterParams; /* not-yet-assigned NestLoopParams */ |
| |
| /* optional private data for join_search_hook, e.g., GEQO */ |
| void *join_search_private; |
| |
| /* Does this query modify any partition key columns? */ |
| bool partColsUpdated; |
| }; |
| |
| |
| /* |
| * In places where it's known that simple_rte_array[] must have been prepared |
| * already, we just index into it to fetch RTEs. In code that might be |
| * executed before or after entering query_planner(), use this macro. |
| */ |
| #define planner_rt_fetch(rti, root) \ |
| ((root)->simple_rte_array ? (root)->simple_rte_array[rti] : \ |
| rt_fetch(rti, (root)->parse->rtable)) |
| |
| /* |
| * If multiple relations are partitioned the same way, all such partitions |
| * will have a pointer to the same PartitionScheme. A list of PartitionScheme |
| * objects is attached to the PlannerInfo. By design, the partition scheme |
| * incorporates only the general properties of the partition method (LIST vs. |
| * RANGE, number of partitioning columns and the type information for each) |
| * and not the specific bounds. |
| * |
| * We store the opclass-declared input data types instead of the partition key |
| * datatypes since the former rather than the latter are used to compare |
| * partition bounds. Since partition key data types and the opclass declared |
| * input data types are expected to be binary compatible (per ResolveOpClass), |
| * both of those should have same byval and length properties. |
| */ |
| typedef struct PartitionSchemeData |
| { |
| char strategy; /* partition strategy */ |
| int16 partnatts; /* number of partition attributes */ |
| Oid *partopfamily; /* OIDs of operator families */ |
| Oid *partopcintype; /* OIDs of opclass declared input data types */ |
| Oid *partcollation; /* OIDs of partitioning collations */ |
| |
| /* Cached information about partition key data types. */ |
| int16 *parttyplen; |
| bool *parttypbyval; |
| |
| /* Cached information about partition comparison functions. */ |
| struct FmgrInfo *partsupfunc; |
| } PartitionSchemeData; |
| |
| typedef struct PartitionSchemeData *PartitionScheme; |
| |
| /*---------- |
| * RelOptInfo |
| * Per-relation information for planning/optimization |
| * |
| * For planning purposes, a "base rel" is either a plain relation (a table) |
| * or the output of a sub-SELECT or function that appears in the range table. |
| * In either case it is uniquely identified by an RT index. A "joinrel" |
| * is the joining of two or more base rels. A joinrel is identified by |
| * the set of RT indexes for its component baserels. We create RelOptInfo |
| * nodes for each baserel and joinrel, and store them in the PlannerInfo's |
| * simple_rel_array and join_rel_list respectively. |
| * |
| * Note that there is only one joinrel for any given set of component |
| * baserels, no matter what order we assemble them in; so an unordered |
| * set is the right datatype to identify it with. |
| * |
| * We also have "other rels", which are like base rels in that they refer to |
| * single RT indexes; but they are not part of the join tree, and are given |
| * a different RelOptKind to identify them. |
| * Currently the only kind of otherrels are those made for member relations |
| * of an "append relation", that is an inheritance set or UNION ALL subquery. |
| * An append relation has a parent RTE that is a base rel, which represents |
| * the entire append relation. The member RTEs are otherrels. The parent |
| * is present in the query join tree but the members are not. The member |
| * RTEs and otherrels are used to plan the scans of the individual tables or |
| * subqueries of the append set; then the parent baserel is given Append |
| * and/or MergeAppend paths comprising the best paths for the individual |
| * member rels. (See comments for AppendRelInfo for more information.) |
| * |
| * At one time we also made otherrels to represent join RTEs, for use in |
| * handling join alias Vars. Currently this is not needed because all join |
| * alias Vars are expanded to non-aliased form during preprocess_expression. |
| * |
| * We also have relations representing joins between child relations of |
| * different partitioned tables. These relations are not added to |
| * join_rel_level lists as they are not joined directly by the dynamic |
| * programming algorithm. |
| * |
| * There is also a RelOptKind for "upper" relations, which are RelOptInfos |
| * that describe post-scan/join processing steps, such as aggregation. |
| * Many of the fields in these RelOptInfos are meaningless, but their Path |
| * fields always hold Paths showing ways to do that processing step. |
| * |
| * Lastly, there is a RelOptKind for "dead" relations, which are base rels |
| * that we have proven we don't need to join after all. |
| * |
| * Parts of this data structure are specific to various scan and join |
| * mechanisms. It didn't seem worth creating new node types for them. |
| * |
| * relids - Set of base-relation identifiers; it is a base relation |
| * if there is just one, a join relation if more than one |
| * rows - estimated number of tuples in the relation after restriction |
| * clauses have been applied (ie, output rows of a plan for it) |
| * consider_startup - true if there is any value in keeping plain paths for |
| * this rel on the basis of having cheap startup cost |
| * consider_param_startup - the same for parameterized paths |
| * reltarget - Default Path output tlist for this rel; normally contains |
| * Var and PlaceHolderVar nodes for the values we need to |
| * output from this relation. |
| * List is in no particular order, but all rels of an |
| * appendrel set must use corresponding orders. |
| * NOTE: in an appendrel child relation, may contain |
| * arbitrary expressions pulled up from a subquery! |
| * pathlist - List of Path nodes, one for each potentially useful |
| * method of generating the relation |
| * ppilist - ParamPathInfo nodes for parameterized Paths, if any |
| * cheapest_startup_path - the pathlist member with lowest startup cost |
| * (regardless of ordering) among the unparameterized paths; |
| * or NULL if there is no unparameterized path |
| * cheapest_total_path - the pathlist member with lowest total cost |
| * (regardless of ordering) among the unparameterized paths; |
| * or if there is no unparameterized path, the path with lowest |
| * total cost among the paths with minimum parameterization |
| * cheapest_unique_path - for caching cheapest path to produce unique |
| * (no duplicates) output from relation; NULL if not yet requested |
| * cheapest_parameterized_paths - best paths for their parameterizations; |
| * always includes cheapest_total_path, even if that's unparameterized |
| * direct_lateral_relids - rels this rel has direct LATERAL references to |
| * lateral_relids - required outer rels for LATERAL, as a Relids set |
| * (includes both direct and indirect lateral references) |
| * |
| * If the relation is a base relation it will have these fields set: |
| * |
| * relid - RTE index (this is redundant with the relids field, but |
| * is provided for convenience of access) |
| * rtekind - copy of RTE's rtekind field |
| * min_attr, max_attr - range of valid AttrNumbers for rel |
| * attr_needed - array of bitmapsets indicating the highest joinrel |
| * in which each attribute is needed; if bit 0 is set then |
| * the attribute is needed as part of final targetlist |
| * attr_widths - cache space for per-attribute width estimates; |
| * zero means not computed yet |
| * lateral_vars - lateral cross-references of rel, if any (list of |
| * Vars and PlaceHolderVars) |
| * lateral_referencers - relids of rels that reference this one laterally |
| * (includes both direct and indirect lateral references) |
| * indexlist - list of IndexOptInfo nodes for relation's indexes |
| * (always NIL if it's not a table) |
| * pages - number of disk pages in relation (zero if not a table) |
| * tuples - number of tuples in relation (not considering restrictions) |
| * allvisfrac - fraction of disk pages that are marked all-visible |
| * eclass_indexes - EquivalenceClasses that mention this rel (filled |
| * only after EC merging is complete) |
| * subroot - PlannerInfo for subquery (NULL if it's not a subquery) |
| * subplan_params - list of PlannerParamItems to be passed to subquery |
| * |
| * Note: for a subquery, tuples and subroot are not set immediately |
| * upon creation of the RelOptInfo object; they are filled in when |
| * set_subquery_pathlist processes the object. |
| * |
| * For otherrels that are appendrel members, these fields are filled |
| * in just as for a baserel, except we don't bother with lateral_vars. |
| * |
| * If the relation is either a foreign table or a join of foreign tables that |
| * all belong to the same foreign server and are assigned to the same user to |
| * check access permissions as (cf checkAsUser), these fields will be set: |
| * |
| * serverid - OID of foreign server, if foreign table (else InvalidOid) |
| * userid - OID of user to check access as (InvalidOid means current user) |
| * useridiscurrent - we've assumed that userid equals current user |
| * fdwroutine - function hooks for FDW, if foreign table (else NULL) |
| * fdw_private - private state for FDW, if foreign table (else NULL) |
| * |
| * Two fields are used to cache knowledge acquired during the join search |
| * about whether this rel is provably unique when being joined to given other |
| * relation(s), ie, it can have at most one row matching any given row from |
| * that join relation. Currently we only attempt such proofs, and thus only |
| * populate these fields, for base rels; but someday they might be used for |
| * join rels too: |
| * |
| * unique_for_rels - list of Relid sets, each one being a set of other |
| * rels for which this one has been proven unique |
| * non_unique_for_rels - list of Relid sets, each one being a set of |
| * other rels for which we have tried and failed to prove |
| * this one unique |
| * |
| * The presence of the following fields depends on the restrictions |
| * and joins that the relation participates in: |
| * |
| * baserestrictinfo - List of RestrictInfo nodes, containing info about |
| * each non-join qualification clause in which this relation |
| * participates (only used for base rels) |
| * baserestrictcost - Estimated cost of evaluating the baserestrictinfo |
| * clauses at a single tuple (only used for base rels) |
| * baserestrict_min_security - Smallest security_level found among |
| * clauses in baserestrictinfo |
| * joininfo - List of RestrictInfo nodes, containing info about each |
| * join clause in which this relation participates (but |
| * note this excludes clauses that might be derivable from |
| * EquivalenceClasses) |
| * has_eclass_joins - flag that EquivalenceClass joins are possible |
| * |
| * Note: Keeping a restrictinfo list in the RelOptInfo is useful only for |
| * base rels, because for a join rel the set of clauses that are treated as |
| * restrict clauses varies depending on which sub-relations we choose to join. |
| * (For example, in a 3-base-rel join, a clause relating rels 1 and 2 must be |
| * treated as a restrictclause if we join {1} and {2 3} to make {1 2 3}; but |
| * if we join {1 2} and {3} then that clause will be a restrictclause in {1 2} |
| * and should not be processed again at the level of {1 2 3}.) Therefore, |
| * the restrictinfo list in the join case appears in individual JoinPaths |
| * (field joinrestrictinfo), not in the parent relation. But it's OK for |
| * the RelOptInfo to store the joininfo list, because that is the same |
| * for a given rel no matter how we form it. |
| * |
| * We store baserestrictcost in the RelOptInfo (for base relations) because |
| * we know we will need it at least once (to price the sequential scan) |
| * and may need it multiple times to price index scans. |
| * |
| * A join relation is considered to be partitioned if it is formed from a |
| * join of two relations that are partitioned, have matching partitioning |
| * schemes, and are joined on an equijoin of the partitioning columns. |
| * Under those conditions we can consider the join relation to be partitioned |
| * by either relation's partitioning keys, though some care is needed if |
| * either relation can be forced to null by outer-joining. For example, an |
| * outer join like (A LEFT JOIN B ON A.a = B.b) may produce rows with B.b |
| * NULL. These rows may not fit the partitioning conditions imposed on B. |
| * Hence, strictly speaking, the join is not partitioned by B.b and thus |
| * partition keys of an outer join should include partition key expressions |
| * from the non-nullable side only. However, if a subsequent join uses |
| * strict comparison operators (and all commonly-used equijoin operators are |
| * strict), the presence of nulls doesn't cause a problem: such rows couldn't |
| * match anything on the other side and thus they don't create a need to do |
| * any cross-partition sub-joins. Hence we can treat such values as still |
| * partitioning the join output for the purpose of additional partitionwise |
| * joining, so long as a strict join operator is used by the next join. |
| * |
| * If the relation is partitioned, these fields will be set: |
| * |
| * part_scheme - Partitioning scheme of the relation |
| * nparts - Number of partitions |
| * boundinfo - Partition bounds |
| * partbounds_merged - true if partition bounds are merged ones |
| * partition_qual - Partition constraint if not the root |
| * part_rels - RelOptInfos for each partition |
| * all_partrels - Relids set of all partition relids |
| * partexprs, nullable_partexprs - Partition key expressions |
| * partitioned_child_rels - RT indexes of unpruned partitions of |
| * this relation that are partitioned tables |
| * themselves, in hierarchical order |
| * |
| * The partexprs and nullable_partexprs arrays each contain |
| * part_scheme->partnatts elements. Each of the elements is a list of |
| * partition key expressions. For partitioned base relations, there is one |
| * expression in each partexprs element, and nullable_partexprs is empty. |
| * For partitioned join relations, each base relation within the join |
| * contributes one partition key expression per partitioning column; |
| * that expression goes in the partexprs[i] list if the base relation |
| * is not nullable by this join or any lower outer join, or in the |
| * nullable_partexprs[i] list if the base relation is nullable. |
| * Furthermore, FULL JOINs add extra nullable_partexprs expressions |
| * corresponding to COALESCE expressions of the left and right join columns, |
| * to simplify matching join clauses to those lists. |
| *---------- |
| */ |
| typedef enum RelOptKind |
| { |
| RELOPT_BASEREL, |
| RELOPT_JOINREL, |
| RELOPT_OTHER_MEMBER_REL, |
| RELOPT_OTHER_JOINREL, |
| RELOPT_UPPER_REL, |
| RELOPT_OTHER_UPPER_REL, |
| RELOPT_DEADREL |
| } RelOptKind; |
| |
| /* |
| * Is the given relation a simple relation i.e a base or "other" member |
| * relation? |
| */ |
| #define IS_SIMPLE_REL(rel) \ |
| ((rel)->reloptkind == RELOPT_BASEREL || \ |
| (rel)->reloptkind == RELOPT_OTHER_MEMBER_REL) |
| |
| /* Is the given relation a join relation? */ |
| #define IS_JOIN_REL(rel) \ |
| ((rel)->reloptkind == RELOPT_JOINREL || \ |
| (rel)->reloptkind == RELOPT_OTHER_JOINREL) |
| |
| /* Is the given relation an upper relation? */ |
| #define IS_UPPER_REL(rel) \ |
| ((rel)->reloptkind == RELOPT_UPPER_REL || \ |
| (rel)->reloptkind == RELOPT_OTHER_UPPER_REL) |
| |
| /* Is the given relation an "other" relation? */ |
| #define IS_OTHER_REL(rel) \ |
| ((rel)->reloptkind == RELOPT_OTHER_MEMBER_REL || \ |
| (rel)->reloptkind == RELOPT_OTHER_JOINREL || \ |
| (rel)->reloptkind == RELOPT_OTHER_UPPER_REL) |
| |
| typedef struct RelOptInfo |
| { |
| NodeTag type; |
| |
| RelOptKind reloptkind; |
| |
| /* all relations included in this RelOptInfo */ |
| Relids relids; /* set of base relids (rangetable indexes) */ |
| |
| /* size estimates generated by planner */ |
| double rows; /* estimated number of result tuples */ |
| |
| /* per-relation planner control flags */ |
| bool consider_startup; /* keep cheap-startup-cost paths? */ |
| bool consider_param_startup; /* ditto, for parameterized paths? */ |
| bool consider_parallel; /* consider parallel paths? */ |
| |
| /* default result targetlist for Paths scanning this relation */ |
| struct PathTarget *reltarget; /* list of Vars/Exprs, cost, width */ |
| |
| /* materialization information */ |
| List *pathlist; /* Path structures */ |
| List *ppilist; /* ParamPathInfos used in pathlist */ |
| List *partial_pathlist; /* partial Paths */ |
| struct Path *cheapest_startup_path; |
| struct Path *cheapest_total_path; |
| struct Path *cheapest_unique_path; |
| List *cheapest_parameterized_paths; |
| |
| /* parameterization information needed for both base rels and join rels */ |
| /* (see also lateral_vars and lateral_referencers) */ |
| Relids direct_lateral_relids; /* rels directly laterally referenced */ |
| Relids lateral_relids; /* minimum parameterization of rel */ |
| |
| /* information about a base rel (not set for join rels!) */ |
| Index relid; |
| Oid reltablespace; /* containing tablespace */ |
| RTEKind rtekind; /* RELATION, SUBQUERY, FUNCTION, etc */ |
| AttrNumber min_attr; /* smallest attrno of rel (often <0) */ |
| AttrNumber max_attr; /* largest attrno of rel */ |
| Relids *attr_needed; /* array indexed [min_attr .. max_attr] */ |
| int32 *attr_widths; /* array indexed [min_attr .. max_attr] */ |
| List *lateral_vars; /* LATERAL Vars and PHVs referenced by rel */ |
| Relids lateral_referencers; /* rels that reference me laterally */ |
| List *indexlist; /* list of IndexOptInfo */ |
| List *statlist; /* list of StatisticExtInfo */ |
| BlockNumber pages; /* size estimates derived from pg_class */ |
| double tuples; |
| double allvisfrac; |
| Bitmapset *eclass_indexes; /* Indexes in PlannerInfo's eq_classes list of |
| * ECs that mention this rel */ |
| PlannerInfo *subroot; /* if subquery */ |
| List *subplan_params; /* if subquery */ |
| int rel_parallel_workers; /* wanted number of parallel workers */ |
| |
| /* Information about foreign tables and foreign joins */ |
| Oid serverid; /* identifies server for the table or join */ |
| Oid userid; /* identifies user to check access as */ |
| bool useridiscurrent; /* join is only valid for current user */ |
| /* use "struct FdwRoutine" to avoid including fdwapi.h here */ |
| struct FdwRoutine *fdwroutine; |
| void *fdw_private; |
| |
| /* cache space for remembering if we have proven this relation unique */ |
| List *unique_for_rels; /* known unique for these other relid |
| * set(s) */ |
| List *non_unique_for_rels; /* known not unique for these set(s) */ |
| |
| /* used by various scans and joins: */ |
| List *baserestrictinfo; /* RestrictInfo structures (if base rel) */ |
| QualCost baserestrictcost; /* cost of evaluating the above */ |
| Index baserestrict_min_security; /* min security_level found in |
| * baserestrictinfo */ |
| List *joininfo; /* RestrictInfo structures for join clauses |
| * involving this rel */ |
| bool has_eclass_joins; /* T means joininfo is incomplete */ |
| |
| /* used by partitionwise joins: */ |
| bool consider_partitionwise_join; /* consider partitionwise join |
| * paths? (if partitioned rel) */ |
| Relids top_parent_relids; /* Relids of topmost parents (if "other" |
| * rel) */ |
| |
| /* used for partitioned relations: */ |
| PartitionScheme part_scheme; /* Partitioning scheme */ |
| int nparts; /* Number of partitions; -1 if not yet set; in |
| * case of a join relation 0 means it's |
| * considered unpartitioned */ |
| struct PartitionBoundInfoData *boundinfo; /* Partition bounds */ |
| bool partbounds_merged; /* True if partition bounds were created |
| * by partition_bounds_merge() */ |
| List *partition_qual; /* Partition constraint, if not the root */ |
| struct RelOptInfo **part_rels; /* Array of RelOptInfos of partitions, |
| * stored in the same order as bounds */ |
| Relids all_partrels; /* Relids set of all partition relids */ |
| List **partexprs; /* Non-nullable partition key expressions */ |
| List **nullable_partexprs; /* Nullable partition key expressions */ |
| List *partitioned_child_rels; /* List of RT indexes */ |
| } RelOptInfo; |
| |
| /* |
| * Is given relation partitioned? |
| * |
| * It's not enough to test whether rel->part_scheme is set, because it might |
| * be that the basic partitioning properties of the input relations matched |
| * but the partition bounds did not. Also, if we are able to prove a rel |
| * dummy (empty), we should henceforth treat it as unpartitioned. |
| */ |
| #define IS_PARTITIONED_REL(rel) \ |
| ((rel)->part_scheme && (rel)->boundinfo && (rel)->nparts > 0 && \ |
| (rel)->part_rels && !IS_DUMMY_REL(rel)) |
| |
| /* |
| * Convenience macro to make sure that a partitioned relation has all the |
| * required members set. |
| */ |
| #define REL_HAS_ALL_PART_PROPS(rel) \ |
| ((rel)->part_scheme && (rel)->boundinfo && (rel)->nparts > 0 && \ |
| (rel)->part_rels && (rel)->partexprs && (rel)->nullable_partexprs) |
| |
| /* |
| * IndexOptInfo |
| * Per-index information for planning/optimization |
| * |
| * indexkeys[], indexcollations[] each have ncolumns entries. |
| * opfamily[], and opcintype[] each have nkeycolumns entries. They do |
| * not contain any information about included attributes. |
| * |
| * sortopfamily[], reverse_sort[], and nulls_first[] have |
| * nkeycolumns entries, if the index is ordered; but if it is unordered, |
| * those pointers are NULL. |
| * |
| * Zeroes in the indexkeys[] array indicate index columns that are |
| * expressions; there is one element in indexprs for each such column. |
| * |
| * For an ordered index, reverse_sort[] and nulls_first[] describe the |
| * sort ordering of a forward indexscan; we can also consider a backward |
| * indexscan, which will generate the reverse ordering. |
| * |
| * The indexprs and indpred expressions have been run through |
| * prepqual.c and eval_const_expressions() for ease of matching to |
| * WHERE clauses. indpred is in implicit-AND form. |
| * |
| * indextlist is a TargetEntry list representing the index columns. |
| * It provides an equivalent base-relation Var for each simple column, |
| * and links to the matching indexprs element for each expression column. |
| * |
| * While most of these fields are filled when the IndexOptInfo is created |
| * (by plancat.c), indrestrictinfo and predOK are set later, in |
| * check_index_predicates(). |
| */ |
| #ifndef HAVE_INDEXOPTINFO_TYPEDEF |
| typedef struct IndexOptInfo IndexOptInfo; |
| #define HAVE_INDEXOPTINFO_TYPEDEF 1 |
| #endif |
| |
| struct IndexOptInfo |
| { |
| NodeTag type; |
| |
| Oid indexoid; /* OID of the index relation */ |
| Oid reltablespace; /* tablespace of index (not table) */ |
| RelOptInfo *rel; /* back-link to index's table */ |
| |
| /* index-size statistics (from pg_class and elsewhere) */ |
| BlockNumber pages; /* number of disk pages in index */ |
| double tuples; /* number of index tuples in index */ |
| int tree_height; /* index tree height, or -1 if unknown */ |
| |
| /* index descriptor information */ |
| int ncolumns; /* number of columns in index */ |
| int nkeycolumns; /* number of key columns in index */ |
| int *indexkeys; /* column numbers of index's attributes both |
| * key and included columns, or 0 */ |
| Oid *indexcollations; /* OIDs of collations of index columns */ |
| Oid *opfamily; /* OIDs of operator families for columns */ |
| Oid *opcintype; /* OIDs of opclass declared input data types */ |
| Oid *sortopfamily; /* OIDs of btree opfamilies, if orderable */ |
| bool *reverse_sort; /* is sort order descending? */ |
| bool *nulls_first; /* do NULLs come first in the sort order? */ |
| bytea **opclassoptions; /* opclass-specific options for columns */ |
| bool *canreturn; /* which index cols can be returned in an |
| * index-only scan? */ |
| Oid relam; /* OID of the access method (in pg_am) */ |
| |
| List *indexprs; /* expressions for non-simple index columns */ |
| List *indpred; /* predicate if a partial index, else NIL */ |
| |
| List *indextlist; /* targetlist representing index columns */ |
| |
| List *indrestrictinfo; /* parent relation's baserestrictinfo |
| * list, less any conditions implied by |
| * the index's predicate (unless it's a |
| * target rel, see comments in |
| * check_index_predicates()) */ |
| |
| bool predOK; /* true if index predicate matches query */ |
| bool unique; /* true if a unique index */ |
| bool immediate; /* is uniqueness enforced immediately? */ |
| bool hypothetical; /* true if index doesn't really exist */ |
| |
| /* Remaining fields are copied from the index AM's API struct: */ |
| bool amcanorderbyop; /* does AM support order by operator result? */ |
| bool amoptionalkey; /* can query omit key for the first column? */ |
| bool amsearcharray; /* can AM handle ScalarArrayOpExpr quals? */ |
| bool amsearchnulls; /* can AM search for NULL/NOT NULL entries? */ |
| bool amhasgettuple; /* does AM have amgettuple interface? */ |
| bool amhasgetbitmap; /* does AM have amgetbitmap interface? */ |
| bool amcanparallel; /* does AM support parallel scan? */ |
| bool amcanmarkpos; /* does AM support mark/restore? */ |
| /* Rather than include amapi.h here, we declare amcostestimate like this */ |
| void (*amcostestimate) (); /* AM's cost estimator */ |
| }; |
| |
| /* |
| * ForeignKeyOptInfo |
| * Per-foreign-key information for planning/optimization |
| * |
| * The per-FK-column arrays can be fixed-size because we allow at most |
| * INDEX_MAX_KEYS columns in a foreign key constraint. Each array has |
| * nkeys valid entries. |
| */ |
| typedef struct ForeignKeyOptInfo |
| { |
| NodeTag type; |
| |
| /* Basic data about the foreign key (fetched from catalogs): */ |
| Index con_relid; /* RT index of the referencing table */ |
| Index ref_relid; /* RT index of the referenced table */ |
| int nkeys; /* number of columns in the foreign key */ |
| AttrNumber conkey[INDEX_MAX_KEYS]; /* cols in referencing table */ |
| AttrNumber confkey[INDEX_MAX_KEYS]; /* cols in referenced table */ |
| Oid conpfeqop[INDEX_MAX_KEYS]; /* PK = FK operator OIDs */ |
| |
| /* Derived info about whether FK's equality conditions match the query: */ |
| int nmatched_ec; /* # of FK cols matched by ECs */ |
| int nmatched_rcols; /* # of FK cols matched by non-EC rinfos */ |
| int nmatched_ri; /* total # of non-EC rinfos matched to FK */ |
| /* Pointer to eclass matching each column's condition, if there is one */ |
| struct EquivalenceClass *eclass[INDEX_MAX_KEYS]; |
| /* List of non-EC RestrictInfos matching each column's condition */ |
| List *rinfos[INDEX_MAX_KEYS]; |
| } ForeignKeyOptInfo; |
| |
| /* |
| * StatisticExtInfo |
| * Information about extended statistics for planning/optimization |
| * |
| * Each pg_statistic_ext row is represented by one or more nodes of this |
| * type, or even zero if ANALYZE has not computed them. |
| */ |
| typedef struct StatisticExtInfo |
| { |
| NodeTag type; |
| |
| Oid statOid; /* OID of the statistics row */ |
| RelOptInfo *rel; /* back-link to statistic's table */ |
| char kind; /* statistics kind of this entry */ |
| Bitmapset *keys; /* attnums of the columns covered */ |
| } StatisticExtInfo; |
| |
| /* |
| * EquivalenceClasses |
| * |
| * Whenever we can determine that a mergejoinable equality clause A = B is |
| * not delayed by any outer join, we create an EquivalenceClass containing |
| * the expressions A and B to record this knowledge. If we later find another |
| * equivalence B = C, we add C to the existing EquivalenceClass; this may |
| * require merging two existing EquivalenceClasses. At the end of the qual |
| * distribution process, we have sets of values that are known all transitively |
| * equal to each other, where "equal" is according to the rules of the btree |
| * operator family(s) shown in ec_opfamilies, as well as the collation shown |
| * by ec_collation. (We restrict an EC to contain only equalities whose |
| * operators belong to the same set of opfamilies. This could probably be |
| * relaxed, but for now it's not worth the trouble, since nearly all equality |
| * operators belong to only one btree opclass anyway. Similarly, we suppose |
| * that all or none of the input datatypes are collatable, so that a single |
| * collation value is sufficient.) |
| * |
| * We also use EquivalenceClasses as the base structure for PathKeys, letting |
| * us represent knowledge about different sort orderings being equivalent. |
| * Since every PathKey must reference an EquivalenceClass, we will end up |
| * with single-member EquivalenceClasses whenever a sort key expression has |
| * not been equivalenced to anything else. It is also possible that such an |
| * EquivalenceClass will contain a volatile expression ("ORDER BY random()"), |
| * which is a case that can't arise otherwise since clauses containing |
| * volatile functions are never considered mergejoinable. We mark such |
| * EquivalenceClasses specially to prevent them from being merged with |
| * ordinary EquivalenceClasses. Also, for volatile expressions we have |
| * to be careful to match the EquivalenceClass to the correct targetlist |
| * entry: consider SELECT random() AS a, random() AS b ... ORDER BY b,a. |
| * So we record the SortGroupRef of the originating sort clause. |
| * |
| * We allow equality clauses appearing below the nullable side of an outer join |
| * to form EquivalenceClasses, but these have a slightly different meaning: |
| * the included values might be all NULL rather than all the same non-null |
| * values. See src/backend/optimizer/README for more on that point. |
| * |
| * NB: if ec_merged isn't NULL, this class has been merged into another, and |
| * should be ignored in favor of using the pointed-to class. |
| */ |
| typedef struct EquivalenceClass |
| { |
| NodeTag type; |
| |
| List *ec_opfamilies; /* btree operator family OIDs */ |
| Oid ec_collation; /* collation, if datatypes are collatable */ |
| List *ec_members; /* list of EquivalenceMembers */ |
| List *ec_sources; /* list of generating RestrictInfos */ |
| List *ec_derives; /* list of derived RestrictInfos */ |
| Relids ec_relids; /* all relids appearing in ec_members, except |
| * for child members (see below) */ |
| bool ec_has_const; /* any pseudoconstants in ec_members? */ |
| bool ec_has_volatile; /* the (sole) member is a volatile expr */ |
| bool ec_below_outer_join; /* equivalence applies below an OJ */ |
| bool ec_broken; /* failed to generate needed clauses? */ |
| Index ec_sortref; /* originating sortclause label, or 0 */ |
| Index ec_min_security; /* minimum security_level in ec_sources */ |
| Index ec_max_security; /* maximum security_level in ec_sources */ |
| struct EquivalenceClass *ec_merged; /* set if merged into another EC */ |
| } EquivalenceClass; |
| |
| /* |
| * If an EC contains a const and isn't below-outer-join, any PathKey depending |
| * on it must be redundant, since there's only one possible value of the key. |
| */ |
| #define EC_MUST_BE_REDUNDANT(eclass) \ |
| ((eclass)->ec_has_const && !(eclass)->ec_below_outer_join) |
| |
| /* |
| * EquivalenceMember - one member expression of an EquivalenceClass |
| * |
| * em_is_child signifies that this element was built by transposing a member |
| * for an appendrel parent relation to represent the corresponding expression |
| * for an appendrel child. These members are used for determining the |
| * pathkeys of scans on the child relation and for explicitly sorting the |
| * child when necessary to build a MergeAppend path for the whole appendrel |
| * tree. An em_is_child member has no impact on the properties of the EC as a |
| * whole; in particular the EC's ec_relids field does NOT include the child |
| * relation. An em_is_child member should never be marked em_is_const nor |
| * cause ec_has_const or ec_has_volatile to be set, either. Thus, em_is_child |
| * members are not really full-fledged members of the EC, but just reflections |
| * or doppelgangers of real members. Most operations on EquivalenceClasses |
| * should ignore em_is_child members, and those that don't should test |
| * em_relids to make sure they only consider relevant members. |
| * |
| * em_datatype is usually the same as exprType(em_expr), but can be |
| * different when dealing with a binary-compatible opfamily; in particular |
| * anyarray_ops would never work without this. Use em_datatype when |
| * looking up a specific btree operator to work with this expression. |
| */ |
| typedef struct EquivalenceMember |
| { |
| NodeTag type; |
| |
| Expr *em_expr; /* the expression represented */ |
| Relids em_relids; /* all relids appearing in em_expr */ |
| Relids em_nullable_relids; /* nullable by lower outer joins */ |
| bool em_is_const; /* expression is pseudoconstant? */ |
| bool em_is_child; /* derived version for a child relation? */ |
| Oid em_datatype; /* the "nominal type" used by the opfamily */ |
| } EquivalenceMember; |
| |
| /* |
| * PathKeys |
| * |
| * The sort ordering of a path is represented by a list of PathKey nodes. |
| * An empty list implies no known ordering. Otherwise the first item |
| * represents the primary sort key, the second the first secondary sort key, |
| * etc. The value being sorted is represented by linking to an |
| * EquivalenceClass containing that value and including pk_opfamily among its |
| * ec_opfamilies. The EquivalenceClass tells which collation to use, too. |
| * This is a convenient method because it makes it trivial to detect |
| * equivalent and closely-related orderings. (See optimizer/README for more |
| * information.) |
| * |
| * Note: pk_strategy is either BTLessStrategyNumber (for ASC) or |
| * BTGreaterStrategyNumber (for DESC). We assume that all ordering-capable |
| * index types will use btree-compatible strategy numbers. |
| */ |
| typedef struct PathKey |
| { |
| NodeTag type; |
| |
| EquivalenceClass *pk_eclass; /* the value that is ordered */ |
| Oid pk_opfamily; /* btree opfamily defining the ordering */ |
| int pk_strategy; /* sort direction (ASC or DESC) */ |
| bool pk_nulls_first; /* do NULLs come before normal values? */ |
| } PathKey; |
| |
| |
| /* |
| * PathTarget |
| * |
| * This struct contains what we need to know during planning about the |
| * targetlist (output columns) that a Path will compute. Each RelOptInfo |
| * includes a default PathTarget, which its individual Paths may simply |
| * reference. However, in some cases a Path may compute outputs different |
| * from other Paths, and in that case we make a custom PathTarget for it. |
| * For example, an indexscan might return index expressions that would |
| * otherwise need to be explicitly calculated. (Note also that "upper" |
| * relations generally don't have useful default PathTargets.) |
| * |
| * exprs contains bare expressions; they do not have TargetEntry nodes on top, |
| * though those will appear in finished Plans. |
| * |
| * sortgrouprefs[] is an array of the same length as exprs, containing the |
| * corresponding sort/group refnos, or zeroes for expressions not referenced |
| * by sort/group clauses. If sortgrouprefs is NULL (which it generally is in |
| * RelOptInfo.reltarget targets; only upper-level Paths contain this info), |
| * we have not identified sort/group columns in this tlist. This allows us to |
| * deal with sort/group refnos when needed with less expense than including |
| * TargetEntry nodes in the exprs list. |
| */ |
| typedef struct PathTarget |
| { |
| NodeTag type; |
| List *exprs; /* list of expressions to be computed */ |
| Index *sortgrouprefs; /* corresponding sort/group refnos, or 0 */ |
| QualCost cost; /* cost of evaluating the expressions */ |
| int width; /* estimated avg width of result tuples */ |
| } PathTarget; |
| |
| /* Convenience macro to get a sort/group refno from a PathTarget */ |
| #define get_pathtarget_sortgroupref(target, colno) \ |
| ((target)->sortgrouprefs ? (target)->sortgrouprefs[colno] : (Index) 0) |
| |
| |
| /* |
| * ParamPathInfo |
| * |
| * All parameterized paths for a given relation with given required outer rels |
| * link to a single ParamPathInfo, which stores common information such as |
| * the estimated rowcount for this parameterization. We do this partly to |
| * avoid recalculations, but mostly to ensure that the estimated rowcount |
| * is in fact the same for every such path. |
| * |
| * Note: ppi_clauses is only used in ParamPathInfos for base relation paths; |
| * in join cases it's NIL because the set of relevant clauses varies depending |
| * on how the join is formed. The relevant clauses will appear in each |
| * parameterized join path's joinrestrictinfo list, instead. |
| */ |
| typedef struct ParamPathInfo |
| { |
| NodeTag type; |
| |
| Relids ppi_req_outer; /* rels supplying parameters used by path */ |
| double ppi_rows; /* estimated number of result tuples */ |
| List *ppi_clauses; /* join clauses available from outer rels */ |
| } ParamPathInfo; |
| |
| |
| /* |
| * Type "Path" is used as-is for sequential-scan paths, as well as some other |
| * simple plan types that we don't need any extra information in the path for. |
| * For other path types it is the first component of a larger struct. |
| * |
| * "pathtype" is the NodeTag of the Plan node we could build from this Path. |
| * It is partially redundant with the Path's NodeTag, but allows us to use |
| * the same Path type for multiple Plan types when there is no need to |
| * distinguish the Plan type during path processing. |
| * |
| * "parent" identifies the relation this Path scans, and "pathtarget" |
| * describes the precise set of output columns the Path would compute. |
| * In simple cases all Paths for a given rel share the same targetlist, |
| * which we represent by having path->pathtarget equal to parent->reltarget. |
| * |
| * "param_info", if not NULL, links to a ParamPathInfo that identifies outer |
| * relation(s) that provide parameter values to each scan of this path. |
| * That means this path can only be joined to those rels by means of nestloop |
| * joins with this path on the inside. Also note that a parameterized path |
| * is responsible for testing all "movable" joinclauses involving this rel |
| * and the specified outer rel(s). |
| * |
| * "rows" is the same as parent->rows in simple paths, but in parameterized |
| * paths and UniquePaths it can be less than parent->rows, reflecting the |
| * fact that we've filtered by extra join conditions or removed duplicates. |
| * |
| * "pathkeys" is a List of PathKey nodes (see above), describing the sort |
| * ordering of the path's output rows. |
| */ |
| typedef struct Path |
| { |
| NodeTag type; |
| |
| NodeTag pathtype; /* tag identifying scan/join method */ |
| |
| RelOptInfo *parent; /* the relation this path can build */ |
| PathTarget *pathtarget; /* list of Vars/Exprs, cost, width */ |
| |
| ParamPathInfo *param_info; /* parameterization info, or NULL if none */ |
| |
| bool parallel_aware; /* engage parallel-aware logic? */ |
| bool parallel_safe; /* OK to use as part of parallel plan? */ |
| int parallel_workers; /* desired # of workers; 0 = not parallel */ |
| |
| /* estimated size/costs for path (see costsize.c for more info) */ |
| double rows; /* estimated number of result tuples */ |
| Cost startup_cost; /* cost expended before fetching any tuples */ |
| Cost total_cost; /* total cost (assuming all tuples fetched) */ |
| |
| List *pathkeys; /* sort ordering of path's output */ |
| /* pathkeys is a List of PathKey nodes; see above */ |
| } Path; |
| |
| /* Macro for extracting a path's parameterization relids; beware double eval */ |
| #define PATH_REQ_OUTER(path) \ |
| ((path)->param_info ? (path)->param_info->ppi_req_outer : (Relids) NULL) |
| |
| /*---------- |
| * IndexPath represents an index scan over a single index. |
| * |
| * This struct is used for both regular indexscans and index-only scans; |
| * path.pathtype is T_IndexScan or T_IndexOnlyScan to show which is meant. |
| * |
| * 'indexinfo' is the index to be scanned. |
| * |
| * 'indexclauses' is a list of IndexClause nodes, each representing one |
| * index-checkable restriction, with implicit AND semantics across the list. |
| * An empty list implies a full index scan. |
| * |
| * 'indexorderbys', if not NIL, is a list of ORDER BY expressions that have |
| * been found to be usable as ordering operators for an amcanorderbyop index. |
| * The list must match the path's pathkeys, ie, one expression per pathkey |
| * in the same order. These are not RestrictInfos, just bare expressions, |
| * since they generally won't yield booleans. It's guaranteed that each |
| * expression has the index key on the left side of the operator. |
| * |
| * 'indexorderbycols' is an integer list of index column numbers (zero-based) |
| * of the same length as 'indexorderbys', showing which index column each |
| * ORDER BY expression is meant to be used with. (There is no restriction |
| * on which index column each ORDER BY can be used with.) |
| * |
| * 'indexscandir' is one of: |
| * ForwardScanDirection: forward scan of an ordered index |
| * BackwardScanDirection: backward scan of an ordered index |
| * NoMovementScanDirection: scan of an unordered index, or don't care |
| * (The executor doesn't care whether it gets ForwardScanDirection or |
| * NoMovementScanDirection for an indexscan, but the planner wants to |
| * distinguish ordered from unordered indexes for building pathkeys.) |
| * |
| * 'indextotalcost' and 'indexselectivity' are saved in the IndexPath so that |
| * we need not recompute them when considering using the same index in a |
| * bitmap index/heap scan (see BitmapHeapPath). The costs of the IndexPath |
| * itself represent the costs of an IndexScan or IndexOnlyScan plan type. |
| *---------- |
| */ |
| typedef struct IndexPath |
| { |
| Path path; |
| IndexOptInfo *indexinfo; |
| List *indexclauses; |
| List *indexorderbys; |
| List *indexorderbycols; |
| ScanDirection indexscandir; |
| Cost indextotalcost; |
| Selectivity indexselectivity; |
| } IndexPath; |
| |
| /* |
| * Each IndexClause references a RestrictInfo node from the query's WHERE |
| * or JOIN conditions, and shows how that restriction can be applied to |
| * the particular index. We support both indexclauses that are directly |
| * usable by the index machinery, which are typically of the form |
| * "indexcol OP pseudoconstant", and those from which an indexable qual |
| * can be derived. The simplest such transformation is that a clause |
| * of the form "pseudoconstant OP indexcol" can be commuted to produce an |
| * indexable qual (the index machinery expects the indexcol to be on the |
| * left always). Another example is that we might be able to extract an |
| * indexable range condition from a LIKE condition, as in "x LIKE 'foo%bar'" |
| * giving rise to "x >= 'foo' AND x < 'fop'". Derivation of such lossy |
| * conditions is done by a planner support function attached to the |
| * indexclause's top-level function or operator. |
| * |
| * indexquals is a list of RestrictInfos for the directly-usable index |
| * conditions associated with this IndexClause. In the simplest case |
| * it's a one-element list whose member is iclause->rinfo. Otherwise, |
| * it contains one or more directly-usable indexqual conditions extracted |
| * from the given clause. The 'lossy' flag indicates whether the |
| * indexquals are semantically equivalent to the original clause, or |
| * represent a weaker condition. |
| * |
| * Normally, indexcol is the index of the single index column the clause |
| * works on, and indexcols is NIL. But if the clause is a RowCompareExpr, |
| * indexcol is the index of the leading column, and indexcols is a list of |
| * all the affected columns. (Note that indexcols matches up with the |
| * columns of the actual indexable RowCompareExpr in indexquals, which |
| * might be different from the original in rinfo.) |
| * |
| * An IndexPath's IndexClause list is required to be ordered by index |
| * column, i.e. the indexcol values must form a nondecreasing sequence. |
| * (The order of multiple clauses for the same index column is unspecified.) |
| */ |
| typedef struct IndexClause |
| { |
| NodeTag type; |
| struct RestrictInfo *rinfo; /* original restriction or join clause */ |
| List *indexquals; /* indexqual(s) derived from it */ |
| bool lossy; /* are indexquals a lossy version of clause? */ |
| AttrNumber indexcol; /* index column the clause uses (zero-based) */ |
| List *indexcols; /* multiple index columns, if RowCompare */ |
| } IndexClause; |
| |
| /* |
| * BitmapHeapPath represents one or more indexscans that generate TID bitmaps |
| * instead of directly accessing the heap, followed by AND/OR combinations |
| * to produce a single bitmap, followed by a heap scan that uses the bitmap. |
| * Note that the output is always considered unordered, since it will come |
| * out in physical heap order no matter what the underlying indexes did. |
| * |
| * The individual indexscans are represented by IndexPath nodes, and any |
| * logic on top of them is represented by a tree of BitmapAndPath and |
| * BitmapOrPath nodes. Notice that we can use the same IndexPath node both |
| * to represent a regular (or index-only) index scan plan, and as the child |
| * of a BitmapHeapPath that represents scanning the same index using a |
| * BitmapIndexScan. The startup_cost and total_cost figures of an IndexPath |
| * always represent the costs to use it as a regular (or index-only) |
| * IndexScan. The costs of a BitmapIndexScan can be computed using the |
| * IndexPath's indextotalcost and indexselectivity. |
| */ |
| typedef struct BitmapHeapPath |
| { |
| Path path; |
| Path *bitmapqual; /* IndexPath, BitmapAndPath, BitmapOrPath */ |
| } BitmapHeapPath; |
| |
| /* |
| * BitmapAndPath represents a BitmapAnd plan node; it can only appear as |
| * part of the substructure of a BitmapHeapPath. The Path structure is |
| * a bit more heavyweight than we really need for this, but for simplicity |
| * we make it a derivative of Path anyway. |
| */ |
| typedef struct BitmapAndPath |
| { |
| Path path; |
| List *bitmapquals; /* IndexPaths and BitmapOrPaths */ |
| Selectivity bitmapselectivity; |
| } BitmapAndPath; |
| |
| /* |
| * BitmapOrPath represents a BitmapOr plan node; it can only appear as |
| * part of the substructure of a BitmapHeapPath. The Path structure is |
| * a bit more heavyweight than we really need for this, but for simplicity |
| * we make it a derivative of Path anyway. |
| */ |
| typedef struct BitmapOrPath |
| { |
| Path path; |
| List *bitmapquals; /* IndexPaths and BitmapAndPaths */ |
| Selectivity bitmapselectivity; |
| } BitmapOrPath; |
| |
| /* |
| * TidPath represents a scan by TID |
| * |
| * tidquals is an implicitly OR'ed list of qual expressions of the form |
| * "CTID = pseudoconstant", or "CTID = ANY(pseudoconstant_array)", |
| * or a CurrentOfExpr for the relation. |
| */ |
| typedef struct TidPath |
| { |
| Path path; |
| List *tidquals; /* qual(s) involving CTID = something */ |
| } TidPath; |
| |
| /* |
| * SubqueryScanPath represents a scan of an unflattened subquery-in-FROM |
| * |
| * Note that the subpath comes from a different planning domain; for example |
| * RTE indexes within it mean something different from those known to the |
| * SubqueryScanPath. path.parent->subroot is the planning context needed to |
| * interpret the subpath. |
| */ |
| typedef struct SubqueryScanPath |
| { |
| Path path; |
| Path *subpath; /* path representing subquery execution */ |
| } SubqueryScanPath; |
| |
| /* |
| * ForeignPath represents a potential scan of a foreign table, foreign join |
| * or foreign upper-relation. |
| * |
| * fdw_private stores FDW private data about the scan. While fdw_private is |
| * not actually touched by the core code during normal operations, it's |
| * generally a good idea to use a representation that can be dumped by |
| * nodeToString(), so that you can examine the structure during debugging |
| * with tools like pprint(). |
| */ |
| typedef struct ForeignPath |
| { |
| Path path; |
| Path *fdw_outerpath; |
| List *fdw_private; |
| } ForeignPath; |
| |
| /* |
| * CustomPath represents a table scan done by some out-of-core extension. |
| * |
| * We provide a set of hooks here - which the provider must take care to set |
| * up correctly - to allow extensions to supply their own methods of scanning |
| * a relation. For example, a provider might provide GPU acceleration, a |
| * cache-based scan, or some other kind of logic we haven't dreamed up yet. |
| * |
| * CustomPaths can be injected into the planning process for a relation by |
| * set_rel_pathlist_hook functions. |
| * |
| * Core code must avoid assuming that the CustomPath is only as large as |
| * the structure declared here; providers are allowed to make it the first |
| * element in a larger structure. (Since the planner never copies Paths, |
| * this doesn't add any complication.) However, for consistency with the |
| * FDW case, we provide a "custom_private" field in CustomPath; providers |
| * may prefer to use that rather than define another struct type. |
| */ |
| |
| struct CustomPathMethods; |
| |
| typedef struct CustomPath |
| { |
| Path path; |
| uint32 flags; /* mask of CUSTOMPATH_* flags, see |
| * nodes/extensible.h */ |
| List *custom_paths; /* list of child Path nodes, if any */ |
| List *custom_private; |
| const struct CustomPathMethods *methods; |
| } CustomPath; |
| |
| /* |
| * AppendPath represents an Append plan, ie, successive execution of |
| * several member plans. |
| * |
| * For partial Append, 'subpaths' contains non-partial subpaths followed by |
| * partial subpaths. |
| * |
| * Note: it is possible for "subpaths" to contain only one, or even no, |
| * elements. These cases are optimized during create_append_plan. |
| * In particular, an AppendPath with no subpaths is a "dummy" path that |
| * is created to represent the case that a relation is provably empty. |
| * (This is a convenient representation because it means that when we build |
| * an appendrel and find that all its children have been excluded, no extra |
| * action is needed to recognize the relation as dummy.) |
| */ |
| typedef struct AppendPath |
| { |
| Path path; |
| /* RT indexes of non-leaf tables in a partition tree */ |
| List *partitioned_rels; |
| List *subpaths; /* list of component Paths */ |
| /* Index of first partial path in subpaths; list_length(subpaths) if none */ |
| int first_partial_path; |
| double limit_tuples; /* hard limit on output tuples, or -1 */ |
| } AppendPath; |
| |
| #define IS_DUMMY_APPEND(p) \ |
| (IsA((p), AppendPath) && ((AppendPath *) (p))->subpaths == NIL) |
| |
| /* |
| * A relation that's been proven empty will have one path that is dummy |
| * (but might have projection paths on top). For historical reasons, |
| * this is provided as a macro that wraps is_dummy_rel(). |
| */ |
| #define IS_DUMMY_REL(r) is_dummy_rel(r) |
| extern bool is_dummy_rel(RelOptInfo *rel); |
| |
| /* |
| * MergeAppendPath represents a MergeAppend plan, ie, the merging of sorted |
| * results from several member plans to produce similarly-sorted output. |
| */ |
| typedef struct MergeAppendPath |
| { |
| Path path; |
| /* RT indexes of non-leaf tables in a partition tree */ |
| List *partitioned_rels; |
| List *subpaths; /* list of component Paths */ |
| double limit_tuples; /* hard limit on output tuples, or -1 */ |
| } MergeAppendPath; |
| |
| /* |
| * GroupResultPath represents use of a Result plan node to compute the |
| * output of a degenerate GROUP BY case, wherein we know we should produce |
| * exactly one row, which might then be filtered by a HAVING qual. |
| * |
| * Note that quals is a list of bare clauses, not RestrictInfos. |
| */ |
| typedef struct GroupResultPath |
| { |
| Path path; |
| List *quals; |
| } GroupResultPath; |
| |
| /* |
| * MaterialPath represents use of a Material plan node, i.e., caching of |
| * the output of its subpath. This is used when the subpath is expensive |
| * and needs to be scanned repeatedly, or when we need mark/restore ability |
| * and the subpath doesn't have it. |
| */ |
| typedef struct MaterialPath |
| { |
| Path path; |
| Path *subpath; |
| } MaterialPath; |
| |
| /* |
| * UniquePath represents elimination of distinct rows from the output of |
| * its subpath. |
| * |
| * This can represent significantly different plans: either hash-based or |
| * sort-based implementation, or a no-op if the input path can be proven |
| * distinct already. The decision is sufficiently localized that it's not |
| * worth having separate Path node types. (Note: in the no-op case, we could |
| * eliminate the UniquePath node entirely and just return the subpath; but |
| * it's convenient to have a UniquePath in the path tree to signal upper-level |
| * routines that the input is known distinct.) |
| */ |
| typedef enum |
| { |
| UNIQUE_PATH_NOOP, /* input is known unique already */ |
| UNIQUE_PATH_HASH, /* use hashing */ |
| UNIQUE_PATH_SORT /* use sorting */ |
| } UniquePathMethod; |
| |
| typedef struct UniquePath |
| { |
| Path path; |
| Path *subpath; |
| UniquePathMethod umethod; |
| List *in_operators; /* equality operators of the IN clause */ |
| List *uniq_exprs; /* expressions to be made unique */ |
| } UniquePath; |
| |
| /* |
| * GatherPath runs several copies of a plan in parallel and collects the |
| * results. The parallel leader may also execute the plan, unless the |
| * single_copy flag is set. |
| */ |
| typedef struct GatherPath |
| { |
| Path path; |
| Path *subpath; /* path for each worker */ |
| bool single_copy; /* don't execute path more than once */ |
| int num_workers; /* number of workers sought to help */ |
| } GatherPath; |
| |
| /* |
| * GatherMergePath runs several copies of a plan in parallel and collects |
| * the results, preserving their common sort order. |
| */ |
| typedef struct GatherMergePath |
| { |
| Path path; |
| Path *subpath; /* path for each worker */ |
| int num_workers; /* number of workers sought to help */ |
| } GatherMergePath; |
| |
| |
| /* |
| * All join-type paths share these fields. |
| */ |
| |
| typedef struct JoinPath |
| { |
| Path path; |
| |
| JoinType jointype; |
| |
| bool inner_unique; /* each outer tuple provably matches no more |
| * than one inner tuple */ |
| |
| Path *outerjoinpath; /* path for the outer side of the join */ |
| Path *innerjoinpath; /* path for the inner side of the join */ |
| |
| List *joinrestrictinfo; /* RestrictInfos to apply to join */ |
| |
| /* |
| * See the notes for RelOptInfo and ParamPathInfo to understand why |
| * joinrestrictinfo is needed in JoinPath, and can't be merged into the |
| * parent RelOptInfo. |
| */ |
| |
| int minhops; |
| int maxhops; |
| } JoinPath; |
| |
| /* |
| * A nested-loop path needs no special fields. |
| */ |
| |
| typedef JoinPath NestPath; |
| |
| /* |
| * A mergejoin path has these fields. |
| * |
| * Unlike other path types, a MergePath node doesn't represent just a single |
| * run-time plan node: it can represent up to four. Aside from the MergeJoin |
| * node itself, there can be a Sort node for the outer input, a Sort node |
| * for the inner input, and/or a Material node for the inner input. We could |
| * represent these nodes by separate path nodes, but considering how many |
| * different merge paths are investigated during a complex join problem, |
| * it seems better to avoid unnecessary palloc overhead. |
| * |
| * path_mergeclauses lists the clauses (in the form of RestrictInfos) |
| * that will be used in the merge. |
| * |
| * Note that the mergeclauses are a subset of the parent relation's |
| * restriction-clause list. Any join clauses that are not mergejoinable |
| * appear only in the parent's restrict list, and must be checked by a |
| * qpqual at execution time. |
| * |
| * outersortkeys (resp. innersortkeys) is NIL if the outer path |
| * (resp. inner path) is already ordered appropriately for the |
| * mergejoin. If it is not NIL then it is a PathKeys list describing |
| * the ordering that must be created by an explicit Sort node. |
| * |
| * skip_mark_restore is true if the executor need not do mark/restore calls. |
| * Mark/restore overhead is usually required, but can be skipped if we know |
| * that the executor need find only one match per outer tuple, and that the |
| * mergeclauses are sufficient to identify a match. In such cases the |
| * executor can immediately advance the outer relation after processing a |
| * match, and therefore it need never back up the inner relation. |
| * |
| * materialize_inner is true if a Material node should be placed atop the |
| * inner input. This may appear with or without an inner Sort step. |
| */ |
| |
| typedef struct MergePath |
| { |
| JoinPath jpath; |
| List *path_mergeclauses; /* join clauses to be used for merge */ |
| List *outersortkeys; /* keys for explicit sort, if any */ |
| List *innersortkeys; /* keys for explicit sort, if any */ |
| bool skip_mark_restore; /* can executor skip mark/restore? */ |
| bool materialize_inner; /* add Materialize to inner? */ |
| } MergePath; |
| |
| /* |
| * A hashjoin path has these fields. |
| * |
| * The remarks above for mergeclauses apply for hashclauses as well. |
| * |
| * Hashjoin does not care what order its inputs appear in, so we have |
| * no need for sortkeys. |
| */ |
| |
| typedef struct HashPath |
| { |
| JoinPath jpath; |
| List *path_hashclauses; /* join clauses used for hashing */ |
| int num_batches; /* number of batches expected */ |
| double inner_rows_total; /* total inner rows expected */ |
| } HashPath; |
| |
| /* |
| * ProjectionPath represents a projection (that is, targetlist computation) |
| * |
| * Nominally, this path node represents using a Result plan node to do a |
| * projection step. However, if the input plan node supports projection, |
| * we can just modify its output targetlist to do the required calculations |
| * directly, and not need a Result. In some places in the planner we can just |
| * jam the desired PathTarget into the input path node (and adjust its cost |
| * accordingly), so we don't need a ProjectionPath. But in other places |
| * it's necessary to not modify the input path node, so we need a separate |
| * ProjectionPath node, which is marked dummy to indicate that we intend to |
| * assign the work to the input plan node. The estimated cost for the |
| * ProjectionPath node will account for whether a Result will be used or not. |
| */ |
| typedef struct ProjectionPath |
| { |
| Path path; |
| Path *subpath; /* path representing input source */ |
| bool dummypp; /* true if no separate Result is needed */ |
| } ProjectionPath; |
| |
| /* |
| * ProjectSetPath represents evaluation of a targetlist that includes |
| * set-returning function(s), which will need to be implemented by a |
| * ProjectSet plan node. |
| */ |
| typedef struct ProjectSetPath |
| { |
| Path path; |
| Path *subpath; /* path representing input source */ |
| } ProjectSetPath; |
| |
| /* |
| * SortPath represents an explicit sort step |
| * |
| * The sort keys are, by definition, the same as path.pathkeys. |
| * |
| * Note: the Sort plan node cannot project, so path.pathtarget must be the |
| * same as the input's pathtarget. |
| */ |
| typedef struct SortPath |
| { |
| Path path; |
| Path *subpath; /* path representing input source */ |
| } SortPath; |
| |
| /* |
| * IncrementalSortPath represents an incremental sort step |
| * |
| * This is like a regular sort, except some leading key columns are assumed |
| * to be ordered already. |
| */ |
| typedef struct IncrementalSortPath |
| { |
| SortPath spath; |
| int nPresortedCols; /* number of presorted columns */ |
| } IncrementalSortPath; |
| |
| /* |
| * GroupPath represents grouping (of presorted input) |
| * |
| * groupClause represents the columns to be grouped on; the input path |
| * must be at least that well sorted. |
| * |
| * We can also apply a qual to the grouped rows (equivalent of HAVING) |
| */ |
| typedef struct GroupPath |
| { |
| Path path; |
| Path *subpath; /* path representing input source */ |
| List *groupClause; /* a list of SortGroupClause's */ |
| List *qual; /* quals (HAVING quals), if any */ |
| } GroupPath; |
| |
| /* |
| * UpperUniquePath represents adjacent-duplicate removal (in presorted input) |
| * |
| * The columns to be compared are the first numkeys columns of the path's |
| * pathkeys. The input is presumed already sorted that way. |
| */ |
| typedef struct UpperUniquePath |
| { |
| Path path; |
| Path *subpath; /* path representing input source */ |
| int numkeys; /* number of pathkey columns to compare */ |
| } UpperUniquePath; |
| |
| /* |
| * AggPath represents generic computation of aggregate functions |
| * |
| * This may involve plain grouping (but not grouping sets), using either |
| * sorted or hashed grouping; for the AGG_SORTED case, the input must be |
| * appropriately presorted. |
| */ |
| typedef struct AggPath |
| { |
| Path path; |
| Path *subpath; /* path representing input source */ |
| AggStrategy aggstrategy; /* basic strategy, see nodes.h */ |
| AggSplit aggsplit; /* agg-splitting mode, see nodes.h */ |
| double numGroups; /* estimated number of groups in input */ |
| uint64 transitionSpace; /* for pass-by-ref transition data */ |
| List *groupClause; /* a list of SortGroupClause's */ |
| List *qual; /* quals (HAVING quals), if any */ |
| } AggPath; |
| |
| /* |
| * Various annotations used for grouping sets in the planner. |
| */ |
| |
| typedef struct GroupingSetData |
| { |
| NodeTag type; |
| List *set; /* grouping set as list of sortgrouprefs */ |
| double numGroups; /* est. number of result groups */ |
| } GroupingSetData; |
| |
| typedef struct RollupData |
| { |
| NodeTag type; |
| List *groupClause; /* applicable subset of parse->groupClause */ |
| List *gsets; /* lists of integer indexes into groupClause */ |
| List *gsets_data; /* list of GroupingSetData */ |
| double numGroups; /* est. number of result groups */ |
| bool hashable; /* can be hashed */ |
| bool is_hashed; /* to be implemented as a hashagg */ |
| } RollupData; |
| |
| /* |
| * GroupingSetsPath represents a GROUPING SETS aggregation |
| */ |
| |
| typedef struct GroupingSetsPath |
| { |
| Path path; |
| Path *subpath; /* path representing input source */ |
| AggStrategy aggstrategy; /* basic strategy */ |
| List *rollups; /* list of RollupData */ |
| List *qual; /* quals (HAVING quals), if any */ |
| uint64 transitionSpace; /* for pass-by-ref transition data */ |
| } GroupingSetsPath; |
| |
| /* |
| * MinMaxAggPath represents computation of MIN/MAX aggregates from indexes |
| */ |
| typedef struct MinMaxAggPath |
| { |
| Path path; |
| List *mmaggregates; /* list of MinMaxAggInfo */ |
| List *quals; /* HAVING quals, if any */ |
| } MinMaxAggPath; |
| |
| /* |
| * WindowAggPath represents generic computation of window functions |
| */ |
| typedef struct WindowAggPath |
| { |
| Path path; |
| Path *subpath; /* path representing input source */ |
| WindowClause *winclause; /* WindowClause we'll be using */ |
| } WindowAggPath; |
| |
| /* |
| * SetOpPath represents a set-operation, that is INTERSECT or EXCEPT |
| */ |
| typedef struct SetOpPath |
| { |
| Path path; |
| Path *subpath; /* path representing input source */ |
| SetOpCmd cmd; /* what to do, see nodes.h */ |
| SetOpStrategy strategy; /* how to do it, see nodes.h */ |
| List *distinctList; /* SortGroupClauses identifying target cols */ |
| AttrNumber flagColIdx; /* where is the flag column, if any */ |
| int firstFlag; /* flag value for first input relation */ |
| double numGroups; /* estimated number of groups in input */ |
| } SetOpPath; |
| |
| /* |
| * RecursiveUnionPath represents a recursive UNION node |
| */ |
| typedef struct RecursiveUnionPath |
| { |
| Path path; |
| Path *leftpath; /* paths representing input sources */ |
| Path *rightpath; |
| List *distinctList; /* SortGroupClauses identifying target cols */ |
| int wtParam; /* ID of Param representing work table */ |
| double numGroups; /* estimated number of groups in input */ |
| } RecursiveUnionPath; |
| |
| /* |
| * LockRowsPath represents acquiring row locks for SELECT FOR UPDATE/SHARE |
| */ |
| typedef struct LockRowsPath |
| { |
| Path path; |
| Path *subpath; /* path representing input source */ |
| List *rowMarks; /* a list of PlanRowMark's */ |
| int epqParam; /* ID of Param for EvalPlanQual re-eval */ |
| } LockRowsPath; |
| |
| /* |
| * ModifyTablePath represents performing INSERT/UPDATE/DELETE modifications |
| * |
| * We represent most things that will be in the ModifyTable plan node |
| * literally, except we have child Path(s) not Plan(s). But analysis of the |
| * OnConflictExpr is deferred to createplan.c, as is collection of FDW data. |
| */ |
| typedef struct ModifyTablePath |
| { |
| Path path; |
| CmdType operation; /* INSERT, UPDATE, or DELETE */ |
| bool canSetTag; /* do we set the command tag/es_processed? */ |
| Index nominalRelation; /* Parent RT index for use of EXPLAIN */ |
| Index rootRelation; /* Root RT index, if target is partitioned */ |
| bool partColsUpdated; /* some part key in hierarchy updated */ |
| List *resultRelations; /* integer list of RT indexes */ |
| List *subpaths; /* Path(s) producing source data */ |
| List *subroots; /* per-target-table PlannerInfos */ |
| List *withCheckOptionLists; /* per-target-table WCO lists */ |
| List *returningLists; /* per-target-table RETURNING tlists */ |
| List *rowMarks; /* PlanRowMarks (non-locking only) */ |
| OnConflictExpr *onconflict; /* ON CONFLICT clause, or NULL */ |
| int epqParam; /* ID of Param for EvalPlanQual re-eval */ |
| } ModifyTablePath; |
| |
| /* |
| * LimitPath represents applying LIMIT/OFFSET restrictions |
| */ |
| typedef struct LimitPath |
| { |
| Path path; |
| Path *subpath; /* path representing input source */ |
| Node *limitOffset; /* OFFSET parameter, or NULL if none */ |
| Node *limitCount; /* COUNT parameter, or NULL if none */ |
| LimitOption limitOption; /* FETCH FIRST with ties or exact number */ |
| } LimitPath; |
| |
| /* |
| * EagerPath represents use of a Eager plan node. |
| */ |
| typedef struct EagerPath |
| { |
| Path path; |
| Path *subpath; |
| List *modifiedlist; |
| } EagerPath; |
| |
| /* |
| * ModifyGraphPath |
| */ |
| typedef struct ModifyGraphPath |
| { |
| Path path; |
| GraphWriteOp operation; |
| bool last; /* is this for the last clause? */ |
| List *targets; /* relation Oid's of target labels */ |
| Path *subpath; /* Path producing source data */ |
| uint32 nr_modify; /* number of clauses that modifies graph |
| before this */ |
| bool detach; /* DETACH DELETE */ |
| bool eagerness; |
| List *pattern; /* graph pattern (list of paths) for CREATE */ |
| List *exprs; /* expression list for DELETE */ |
| List *sets; /* list of GraphSetProp's for SET/REMOVE */ |
| int epqParam; |
| } ModifyGraphPath; |
| |
| typedef struct ShortestpathPath |
| { |
| JoinPath jpath; |
| Node *end_id_left; |
| Node *end_id_right; |
| Node *tableoid_left; |
| Node *tableoid_right; |
| Node *ctid_left; |
| Node *ctid_right; |
| Node *source; |
| Node *target; |
| long minhops; |
| long maxhops; |
| long limit; |
| } ShortestpathPath; |
| |
| typedef struct DijkstraPath |
| { |
| Path path; |
| Path *subpath; |
| int weight; |
| bool weight_out; |
| Node *end_id; |
| Node *edge_id; |
| Node *source; |
| Node *target; |
| Node *limit; |
| } DijkstraPath; |
| |
| /* |
| * Restriction clause info. |
| * |
| * We create one of these for each AND sub-clause of a restriction condition |
| * (WHERE or JOIN/ON clause). Since the restriction clauses are logically |
| * ANDed, we can use any one of them or any subset of them to filter out |
| * tuples, without having to evaluate the rest. The RestrictInfo node itself |
| * stores data used by the optimizer while choosing the best query plan. |
| * |
| * If a restriction clause references a single base relation, it will appear |
| * in the baserestrictinfo list of the RelOptInfo for that base rel. |
| * |
| * If a restriction clause references more than one base rel, it will |
| * appear in the joininfo list of every RelOptInfo that describes a strict |
| * subset of the base rels mentioned in the clause. The joininfo lists are |
| * used to drive join tree building by selecting plausible join candidates. |
| * The clause cannot actually be applied until we have built a join rel |
| * containing all the base rels it references, however. |
| * |
| * When we construct a join rel that includes all the base rels referenced |
| * in a multi-relation restriction clause, we place that clause into the |
| * joinrestrictinfo lists of paths for the join rel, if neither left nor |
| * right sub-path includes all base rels referenced in the clause. The clause |
| * will be applied at that join level, and will not propagate any further up |
| * the join tree. (Note: the "predicate migration" code was once intended to |
| * push restriction clauses up and down the plan tree based on evaluation |
| * costs, but it's dead code and is unlikely to be resurrected in the |
| * foreseeable future.) |
| * |
| * Note that in the presence of more than two rels, a multi-rel restriction |
| * might reach different heights in the join tree depending on the join |
| * sequence we use. So, these clauses cannot be associated directly with |
| * the join RelOptInfo, but must be kept track of on a per-join-path basis. |
| * |
| * RestrictInfos that represent equivalence conditions (i.e., mergejoinable |
| * equalities that are not outerjoin-delayed) are handled a bit differently. |
| * Initially we attach them to the EquivalenceClasses that are derived from |
| * them. When we construct a scan or join path, we look through all the |
| * EquivalenceClasses and generate derived RestrictInfos representing the |
| * minimal set of conditions that need to be checked for this particular scan |
| * or join to enforce that all members of each EquivalenceClass are in fact |
| * equal in all rows emitted by the scan or join. |
| * |
| * When dealing with outer joins we have to be very careful about pushing qual |
| * clauses up and down the tree. An outer join's own JOIN/ON conditions must |
| * be evaluated exactly at that join node, unless they are "degenerate" |
| * conditions that reference only Vars from the nullable side of the join. |
| * Quals appearing in WHERE or in a JOIN above the outer join cannot be pushed |
| * down below the outer join, if they reference any nullable Vars. |
| * RestrictInfo nodes contain a flag to indicate whether a qual has been |
| * pushed down to a lower level than its original syntactic placement in the |
| * join tree would suggest. If an outer join prevents us from pushing a qual |
| * down to its "natural" semantic level (the level associated with just the |
| * base rels used in the qual) then we mark the qual with a "required_relids" |
| * value including more than just the base rels it actually uses. By |
| * pretending that the qual references all the rels required to form the outer |
| * join, we prevent it from being evaluated below the outer join's joinrel. |
| * When we do form the outer join's joinrel, we still need to distinguish |
| * those quals that are actually in that join's JOIN/ON condition from those |
| * that appeared elsewhere in the tree and were pushed down to the join rel |
| * because they used no other rels. That's what the is_pushed_down flag is |
| * for; it tells us that a qual is not an OUTER JOIN qual for the set of base |
| * rels listed in required_relids. A clause that originally came from WHERE |
| * or an INNER JOIN condition will *always* have its is_pushed_down flag set. |
| * It's possible for an OUTER JOIN clause to be marked is_pushed_down too, |
| * if we decide that it can be pushed down into the nullable side of the join. |
| * In that case it acts as a plain filter qual for wherever it gets evaluated. |
| * (In short, is_pushed_down is only false for non-degenerate outer join |
| * conditions. Possibly we should rename it to reflect that meaning? But |
| * see also the comments for RINFO_IS_PUSHED_DOWN, below.) |
| * |
| * RestrictInfo nodes also contain an outerjoin_delayed flag, which is true |
| * if the clause's applicability must be delayed due to any outer joins |
| * appearing below it (ie, it has to be postponed to some join level higher |
| * than the set of relations it actually references). |
| * |
| * There is also an outer_relids field, which is NULL except for outer join |
| * clauses; for those, it is the set of relids on the outer side of the |
| * clause's outer join. (These are rels that the clause cannot be applied to |
| * in parameterized scans, since pushing it into the join's outer side would |
| * lead to wrong answers.) |
| * |
| * There is also a nullable_relids field, which is the set of rels the clause |
| * references that can be forced null by some outer join below the clause. |
| * |
| * outerjoin_delayed = true is subtly different from nullable_relids != NULL: |
| * a clause might reference some nullable rels and yet not be |
| * outerjoin_delayed because it also references all the other rels of the |
| * outer join(s). A clause that is not outerjoin_delayed can be enforced |
| * anywhere it is computable. |
| * |
| * To handle security-barrier conditions efficiently, we mark RestrictInfo |
| * nodes with a security_level field, in which higher values identify clauses |
| * coming from less-trusted sources. The exact semantics are that a clause |
| * cannot be evaluated before another clause with a lower security_level value |
| * unless the first clause is leakproof. As with outer-join clauses, this |
| * creates a reason for clauses to sometimes need to be evaluated higher in |
| * the join tree than their contents would suggest; and even at a single plan |
| * node, this rule constrains the order of application of clauses. |
| * |
| * In general, the referenced clause might be arbitrarily complex. The |
| * kinds of clauses we can handle as indexscan quals, mergejoin clauses, |
| * or hashjoin clauses are limited (e.g., no volatile functions). The code |
| * for each kind of path is responsible for identifying the restrict clauses |
| * it can use and ignoring the rest. Clauses not implemented by an indexscan, |
| * mergejoin, or hashjoin will be placed in the plan qual or joinqual field |
| * of the finished Plan node, where they will be enforced by general-purpose |
| * qual-expression-evaluation code. (But we are still entitled to count |
| * their selectivity when estimating the result tuple count, if we |
| * can guess what it is...) |
| * |
| * When the referenced clause is an OR clause, we generate a modified copy |
| * in which additional RestrictInfo nodes are inserted below the top-level |
| * OR/AND structure. This is a convenience for OR indexscan processing: |
| * indexquals taken from either the top level or an OR subclause will have |
| * associated RestrictInfo nodes. |
| * |
| * The can_join flag is set true if the clause looks potentially useful as |
| * a merge or hash join clause, that is if it is a binary opclause with |
| * nonoverlapping sets of relids referenced in the left and right sides. |
| * (Whether the operator is actually merge or hash joinable isn't checked, |
| * however.) |
| * |
| * The pseudoconstant flag is set true if the clause contains no Vars of |
| * the current query level and no volatile functions. Such a clause can be |
| * pulled out and used as a one-time qual in a gating Result node. We keep |
| * pseudoconstant clauses in the same lists as other RestrictInfos so that |
| * the regular clause-pushing machinery can assign them to the correct join |
| * level, but they need to be treated specially for cost and selectivity |
| * estimates. Note that a pseudoconstant clause can never be an indexqual |
| * or merge or hash join clause, so it's of no interest to large parts of |
| * the planner. |
| * |
| * When join clauses are generated from EquivalenceClasses, there may be |
| * several equally valid ways to enforce join equivalence, of which we need |
| * apply only one. We mark clauses of this kind by setting parent_ec to |
| * point to the generating EquivalenceClass. Multiple clauses with the same |
| * parent_ec in the same join are redundant. |
| */ |
| |
| typedef struct RestrictInfo |
| { |
| NodeTag type; |
| |
| Expr *clause; /* the represented clause of WHERE or JOIN */ |
| |
| bool is_pushed_down; /* true if clause was pushed down in level */ |
| |
| bool outerjoin_delayed; /* true if delayed by lower outer join */ |
| |
| bool can_join; /* see comment above */ |
| |
| bool pseudoconstant; /* see comment above */ |
| |
| bool leakproof; /* true if known to contain no leaked Vars */ |
| |
| Index security_level; /* see comment above */ |
| |
| /* The set of relids (varnos) actually referenced in the clause: */ |
| Relids clause_relids; |
| |
| /* The set of relids required to evaluate the clause: */ |
| Relids required_relids; |
| |
| /* If an outer-join clause, the outer-side relations, else NULL: */ |
| Relids outer_relids; |
| |
| /* The relids used in the clause that are nullable by lower outer joins: */ |
| Relids nullable_relids; |
| |
| /* These fields are set for any binary opclause: */ |
| Relids left_relids; /* relids in left side of clause */ |
| Relids right_relids; /* relids in right side of clause */ |
| |
| /* This field is NULL unless clause is an OR clause: */ |
| Expr *orclause; /* modified clause with RestrictInfos */ |
| |
| /* This field is NULL unless clause is potentially redundant: */ |
| EquivalenceClass *parent_ec; /* generating EquivalenceClass */ |
| |
| /* cache space for cost and selectivity */ |
| QualCost eval_cost; /* eval cost of clause; -1 if not yet set */ |
| Selectivity norm_selec; /* selectivity for "normal" (JOIN_INNER) |
| * semantics; -1 if not yet set; >1 means a |
| * redundant clause */ |
| Selectivity outer_selec; /* selectivity for outer join semantics; -1 if |
| * not yet set */ |
| |
| /* valid if clause is mergejoinable, else NIL */ |
| List *mergeopfamilies; /* opfamilies containing clause operator */ |
| |
| /* cache space for mergeclause processing; NULL if not yet set */ |
| EquivalenceClass *left_ec; /* EquivalenceClass containing lefthand */ |
| EquivalenceClass *right_ec; /* EquivalenceClass containing righthand */ |
| EquivalenceMember *left_em; /* EquivalenceMember for lefthand */ |
| EquivalenceMember *right_em; /* EquivalenceMember for righthand */ |
| List *scansel_cache; /* list of MergeScanSelCache structs */ |
| |
| /* transient workspace for use while considering a specific join path */ |
| bool outer_is_left; /* T = outer var on left, F = on right */ |
| |
| /* valid if clause is hashjoinable, else InvalidOid: */ |
| Oid hashjoinoperator; /* copy of clause operator */ |
| |
| /* cache space for hashclause processing; -1 if not yet set */ |
| Selectivity left_bucketsize; /* avg bucketsize of left side */ |
| Selectivity right_bucketsize; /* avg bucketsize of right side */ |
| Selectivity left_mcvfreq; /* left side's most common val's freq */ |
| Selectivity right_mcvfreq; /* right side's most common val's freq */ |
| } RestrictInfo; |
| |
| /* |
| * This macro embodies the correct way to test whether a RestrictInfo is |
| * "pushed down" to a given outer join, that is, should be treated as a filter |
| * clause rather than a join clause at that outer join. This is certainly so |
| * if is_pushed_down is true; but examining that is not sufficient anymore, |
| * because outer-join clauses will get pushed down to lower outer joins when |
| * we generate a path for the lower outer join that is parameterized by the |
| * LHS of the upper one. We can detect such a clause by noting that its |
| * required_relids exceed the scope of the join. |
| */ |
| #define RINFO_IS_PUSHED_DOWN(rinfo, joinrelids) \ |
| ((rinfo)->is_pushed_down || \ |
| !bms_is_subset((rinfo)->required_relids, joinrelids)) |
| |
| /* |
| * Since mergejoinscansel() is a relatively expensive function, and would |
| * otherwise be invoked many times while planning a large join tree, |
| * we go out of our way to cache its results. Each mergejoinable |
| * RestrictInfo carries a list of the specific sort orderings that have |
| * been considered for use with it, and the resulting selectivities. |
| */ |
| typedef struct MergeScanSelCache |
| { |
| /* Ordering details (cache lookup key) */ |
| Oid opfamily; /* btree opfamily defining the ordering */ |
| Oid collation; /* collation for the ordering */ |
| int strategy; /* sort direction (ASC or DESC) */ |
| bool nulls_first; /* do NULLs come before normal values? */ |
| /* Results */ |
| Selectivity leftstartsel; /* first-join fraction for clause left side */ |
| Selectivity leftendsel; /* last-join fraction for clause left side */ |
| Selectivity rightstartsel; /* first-join fraction for clause right side */ |
| Selectivity rightendsel; /* last-join fraction for clause right side */ |
| } MergeScanSelCache; |
| |
| /* |
| * Placeholder node for an expression to be evaluated below the top level |
| * of a plan tree. This is used during planning to represent the contained |
| * expression. At the end of the planning process it is replaced by either |
| * the contained expression or a Var referring to a lower-level evaluation of |
| * the contained expression. Typically the evaluation occurs below an outer |
| * join, and Var references above the outer join might thereby yield NULL |
| * instead of the expression value. |
| * |
| * Although the planner treats this as an expression node type, it is not |
| * recognized by the parser or executor, so we declare it here rather than |
| * in primnodes.h. |
| */ |
| |
| typedef struct PlaceHolderVar |
| { |
| Expr xpr; |
| Expr *phexpr; /* the represented expression */ |
| Relids phrels; /* base relids syntactically within expr src */ |
| Index phid; /* ID for PHV (unique within planner run) */ |
| Index phlevelsup; /* > 0 if PHV belongs to outer query */ |
| } PlaceHolderVar; |
| |
| /* |
| * "Special join" info. |
| * |
| * One-sided outer joins constrain the order of joining partially but not |
| * completely. We flatten such joins into the planner's top-level list of |
| * relations to join, but record information about each outer join in a |
| * SpecialJoinInfo struct. These structs are kept in the PlannerInfo node's |
| * join_info_list. |
| * |
| * Similarly, semijoins and antijoins created by flattening IN (subselect) |
| * and EXISTS(subselect) clauses create partial constraints on join order. |
| * These are likewise recorded in SpecialJoinInfo structs. |
| * |
| * We make SpecialJoinInfos for FULL JOINs even though there is no flexibility |
| * of planning for them, because this simplifies make_join_rel()'s API. |
| * |
| * min_lefthand and min_righthand are the sets of base relids that must be |
| * available on each side when performing the special join. lhs_strict is |
| * true if the special join's condition cannot succeed when the LHS variables |
| * are all NULL (this means that an outer join can commute with upper-level |
| * outer joins even if it appears in their RHS). We don't bother to set |
| * lhs_strict for FULL JOINs, however. |
| * |
| * It is not valid for either min_lefthand or min_righthand to be empty sets; |
| * if they were, this would break the logic that enforces join order. |
| * |
| * syn_lefthand and syn_righthand are the sets of base relids that are |
| * syntactically below this special join. (These are needed to help compute |
| * min_lefthand and min_righthand for higher joins.) |
| * |
| * delay_upper_joins is set true if we detect a pushed-down clause that has |
| * to be evaluated after this join is formed (because it references the RHS). |
| * Any outer joins that have such a clause and this join in their RHS cannot |
| * commute with this join, because that would leave noplace to check the |
| * pushed-down clause. (We don't track this for FULL JOINs, either.) |
| * |
| * For a semijoin, we also extract the join operators and their RHS arguments |
| * and set semi_operators, semi_rhs_exprs, semi_can_btree, and semi_can_hash. |
| * This is done in support of possibly unique-ifying the RHS, so we don't |
| * bother unless at least one of semi_can_btree and semi_can_hash can be set |
| * true. (You might expect that this information would be computed during |
| * join planning; but it's helpful to have it available during planning of |
| * parameterized table scans, so we store it in the SpecialJoinInfo structs.) |
| * |
| * jointype is never JOIN_RIGHT; a RIGHT JOIN is handled by switching |
| * the inputs to make it a LEFT JOIN. So the allowed values of jointype |
| * in a join_info_list member are only LEFT, FULL, SEMI, or ANTI. |
| * |
| * For purposes of join selectivity estimation, we create transient |
| * SpecialJoinInfo structures for regular inner joins; so it is possible |
| * to have jointype == JOIN_INNER in such a structure, even though this is |
| * not allowed within join_info_list. We also create transient |
| * SpecialJoinInfos with jointype == JOIN_INNER for outer joins, since for |
| * cost estimation purposes it is sometimes useful to know the join size under |
| * plain innerjoin semantics. Note that lhs_strict, delay_upper_joins, and |
| * of course the semi_xxx fields are not set meaningfully within such structs. |
| */ |
| #ifndef HAVE_SPECIALJOININFO_TYPEDEF |
| typedef struct SpecialJoinInfo SpecialJoinInfo; |
| #define HAVE_SPECIALJOININFO_TYPEDEF 1 |
| #endif |
| |
| struct SpecialJoinInfo |
| { |
| NodeTag type; |
| Relids min_lefthand; /* base relids in minimum LHS for join */ |
| Relids min_righthand; /* base relids in minimum RHS for join */ |
| Relids syn_lefthand; /* base relids syntactically within LHS */ |
| Relids syn_righthand; /* base relids syntactically within RHS */ |
| JoinType jointype; /* always INNER, LEFT, FULL, SEMI, or ANTI */ |
| bool lhs_strict; /* joinclause is strict for some LHS rel */ |
| bool delay_upper_joins; /* can't commute with upper RHS */ |
| /* Remaining fields are set only for JOIN_SEMI jointype: */ |
| bool semi_can_btree; /* true if semi_operators are all btree */ |
| bool semi_can_hash; /* true if semi_operators are all hash */ |
| List *semi_operators; /* OIDs of equality join operators */ |
| List *semi_rhs_exprs; /* righthand-side expressions of these ops */ |
| /* Fields for JOIN_VLE */ |
| int min_hops; |
| int max_hops; |
| }; |
| |
| /* |
| * Append-relation info. |
| * |
| * When we expand an inheritable table or a UNION-ALL subselect into an |
| * "append relation" (essentially, a list of child RTEs), we build an |
| * AppendRelInfo for each child RTE. The list of AppendRelInfos indicates |
| * which child RTEs must be included when expanding the parent, and each node |
| * carries information needed to translate between columns of the parent and |
| * columns of the child. |
| * |
| * These structs are kept in the PlannerInfo node's append_rel_list, with |
| * append_rel_array[] providing a convenient lookup method for the struct |
| * associated with a particular child relid (there can be only one, though |
| * parent rels may have many entries in append_rel_list). |
| * |
| * Note: after completion of the planner prep phase, any given RTE is an |
| * append parent having entries in append_rel_list if and only if its |
| * "inh" flag is set. We clear "inh" for plain tables that turn out not |
| * to have inheritance children, and (in an abuse of the original meaning |
| * of the flag) we set "inh" for subquery RTEs that turn out to be |
| * flattenable UNION ALL queries. This lets us avoid useless searches |
| * of append_rel_list. |
| * |
| * Note: the data structure assumes that append-rel members are single |
| * baserels. This is OK for inheritance, but it prevents us from pulling |
| * up a UNION ALL member subquery if it contains a join. While that could |
| * be fixed with a more complex data structure, at present there's not much |
| * point because no improvement in the plan could result. |
| */ |
| |
| typedef struct AppendRelInfo |
| { |
| NodeTag type; |
| |
| /* |
| * These fields uniquely identify this append relationship. There can be |
| * (in fact, always should be) multiple AppendRelInfos for the same |
| * parent_relid, but never more than one per child_relid, since a given |
| * RTE cannot be a child of more than one append parent. |
| */ |
| Index parent_relid; /* RT index of append parent rel */ |
| Index child_relid; /* RT index of append child rel */ |
| |
| /* |
| * For an inheritance appendrel, the parent and child are both regular |
| * relations, and we store their rowtype OIDs here for use in translating |
| * whole-row Vars. For a UNION-ALL appendrel, the parent and child are |
| * both subqueries with no named rowtype, and we store InvalidOid here. |
| */ |
| Oid parent_reltype; /* OID of parent's composite type */ |
| Oid child_reltype; /* OID of child's composite type */ |
| |
| /* |
| * The N'th element of this list is a Var or expression representing the |
| * child column corresponding to the N'th column of the parent. This is |
| * used to translate Vars referencing the parent rel into references to |
| * the child. A list element is NULL if it corresponds to a dropped |
| * column of the parent (this is only possible for inheritance cases, not |
| * UNION ALL). The list elements are always simple Vars for inheritance |
| * cases, but can be arbitrary expressions in UNION ALL cases. |
| * |
| * Notice we only store entries for user columns (attno > 0). Whole-row |
| * Vars are special-cased, and system columns (attno < 0) need no special |
| * translation since their attnos are the same for all tables. |
| * |
| * Caution: the Vars have varlevelsup = 0. Be careful to adjust as needed |
| * when copying into a subquery. |
| */ |
| List *translated_vars; /* Expressions in the child's Vars */ |
| |
| /* |
| * This array simplifies translations in the reverse direction, from |
| * child's column numbers to parent's. The entry at [ccolno - 1] is the |
| * 1-based parent column number for child column ccolno, or zero if that |
| * child column is dropped or doesn't exist in the parent. |
| */ |
| int num_child_cols; /* length of array */ |
| AttrNumber *parent_colnos; /* array of parent attnos, or zeroes */ |
| |
| /* |
| * We store the parent table's OID here for inheritance, or InvalidOid for |
| * UNION ALL. This is only needed to help in generating error messages if |
| * an attempt is made to reference a dropped parent column. |
| */ |
| Oid parent_reloid; /* OID of parent relation */ |
| } AppendRelInfo; |
| |
| /* |
| * For each distinct placeholder expression generated during planning, we |
| * store a PlaceHolderInfo node in the PlannerInfo node's placeholder_list. |
| * This stores info that is needed centrally rather than in each copy of the |
| * PlaceHolderVar. The phid fields identify which PlaceHolderInfo goes with |
| * each PlaceHolderVar. Note that phid is unique throughout a planner run, |
| * not just within a query level --- this is so that we need not reassign ID's |
| * when pulling a subquery into its parent. |
| * |
| * The idea is to evaluate the expression at (only) the ph_eval_at join level, |
| * then allow it to bubble up like a Var until the ph_needed join level. |
| * ph_needed has the same definition as attr_needed for a regular Var. |
| * |
| * The PlaceHolderVar's expression might contain LATERAL references to vars |
| * coming from outside its syntactic scope. If so, those rels are *not* |
| * included in ph_eval_at, but they are recorded in ph_lateral. |
| * |
| * Notice that when ph_eval_at is a join rather than a single baserel, the |
| * PlaceHolderInfo may create constraints on join order: the ph_eval_at join |
| * has to be formed below any outer joins that should null the PlaceHolderVar. |
| * |
| * We create a PlaceHolderInfo only after determining that the PlaceHolderVar |
| * is actually referenced in the plan tree, so that unreferenced placeholders |
| * don't result in unnecessary constraints on join order. |
| */ |
| |
| typedef struct PlaceHolderInfo |
| { |
| NodeTag type; |
| |
| Index phid; /* ID for PH (unique within planner run) */ |
| PlaceHolderVar *ph_var; /* copy of PlaceHolderVar tree */ |
| Relids ph_eval_at; /* lowest level we can evaluate value at */ |
| Relids ph_lateral; /* relids of contained lateral refs, if any */ |
| Relids ph_needed; /* highest level the value is needed at */ |
| int32 ph_width; /* estimated attribute width */ |
| } PlaceHolderInfo; |
| |
| /* |
| * This struct describes one potentially index-optimizable MIN/MAX aggregate |
| * function. MinMaxAggPath contains a list of these, and if we accept that |
| * path, the list is stored into root->minmax_aggs for use during setrefs.c. |
| */ |
| typedef struct MinMaxAggInfo |
| { |
| NodeTag type; |
| |
| Oid aggfnoid; /* pg_proc Oid of the aggregate */ |
| Oid aggsortop; /* Oid of its sort operator */ |
| Expr *target; /* expression we are aggregating on */ |
| PlannerInfo *subroot; /* modified "root" for planning the subquery */ |
| Path *path; /* access path for subquery */ |
| Cost pathcost; /* estimated cost to fetch first row */ |
| Param *param; /* param for subplan's output */ |
| } MinMaxAggInfo; |
| |
| /* |
| * At runtime, PARAM_EXEC slots are used to pass values around from one plan |
| * node to another. They can be used to pass values down into subqueries (for |
| * outer references in subqueries), or up out of subqueries (for the results |
| * of a subplan), or from a NestLoop plan node into its inner relation (when |
| * the inner scan is parameterized with values from the outer relation). |
| * The planner is responsible for assigning nonconflicting PARAM_EXEC IDs to |
| * the PARAM_EXEC Params it generates. |
| * |
| * Outer references are managed via root->plan_params, which is a list of |
| * PlannerParamItems. While planning a subquery, each parent query level's |
| * plan_params contains the values required from it by the current subquery. |
| * During create_plan(), we use plan_params to track values that must be |
| * passed from outer to inner sides of NestLoop plan nodes. |
| * |
| * The item a PlannerParamItem represents can be one of three kinds: |
| * |
| * A Var: the slot represents a variable of this level that must be passed |
| * down because subqueries have outer references to it, or must be passed |
| * from a NestLoop node to its inner scan. The varlevelsup value in the Var |
| * will always be zero. |
| * |
| * A PlaceHolderVar: this works much like the Var case, except that the |
| * entry is a PlaceHolderVar node with a contained expression. The PHV |
| * will have phlevelsup = 0, and the contained expression is adjusted |
| * to match in level. |
| * |
| * An Aggref (with an expression tree representing its argument): the slot |
| * represents an aggregate expression that is an outer reference for some |
| * subquery. The Aggref itself has agglevelsup = 0, and its argument tree |
| * is adjusted to match in level. |
| * |
| * Note: we detect duplicate Var and PlaceHolderVar parameters and coalesce |
| * them into one slot, but we do not bother to do that for Aggrefs. |
| * The scope of duplicate-elimination only extends across the set of |
| * parameters passed from one query level into a single subquery, or for |
| * nestloop parameters across the set of nestloop parameters used in a single |
| * query level. So there is no possibility of a PARAM_EXEC slot being used |
| * for conflicting purposes. |
| * |
| * In addition, PARAM_EXEC slots are assigned for Params representing outputs |
| * from subplans (values that are setParam items for those subplans). These |
| * IDs need not be tracked via PlannerParamItems, since we do not need any |
| * duplicate-elimination nor later processing of the represented expressions. |
| * Instead, we just record the assignment of the slot number by appending to |
| * root->glob->paramExecTypes. |
| */ |
| typedef struct PlannerParamItem |
| { |
| NodeTag type; |
| |
| Node *item; /* the Var, PlaceHolderVar, or Aggref */ |
| int paramId; /* its assigned PARAM_EXEC slot number */ |
| } PlannerParamItem; |
| |
| /* |
| * When making cost estimates for a SEMI/ANTI/inner_unique join, there are |
| * some correction factors that are needed in both nestloop and hash joins |
| * to account for the fact that the executor can stop scanning inner rows |
| * as soon as it finds a match to the current outer row. These numbers |
| * depend only on the selected outer and inner join relations, not on the |
| * particular paths used for them, so it's worthwhile to calculate them |
| * just once per relation pair not once per considered path. This struct |
| * is filled by compute_semi_anti_join_factors and must be passed along |
| * to the join cost estimation functions. |
| * |
| * outer_match_frac is the fraction of the outer tuples that are |
| * expected to have at least one match. |
| * match_count is the average number of matches expected for |
| * outer tuples that have at least one match. |
| */ |
| typedef struct SemiAntiJoinFactors |
| { |
| Selectivity outer_match_frac; |
| Selectivity match_count; |
| } SemiAntiJoinFactors; |
| |
| /* |
| * Struct for extra information passed to subroutines of add_paths_to_joinrel |
| * |
| * restrictlist contains all of the RestrictInfo nodes for restriction |
| * clauses that apply to this join |
| * mergeclause_list is a list of RestrictInfo nodes for available |
| * mergejoin clauses in this join |
| * inner_unique is true if each outer tuple provably matches no more |
| * than one inner tuple |
| * sjinfo is extra info about special joins for selectivity estimation |
| * semifactors is as shown above (only valid for SEMI/ANTI/inner_unique joins) |
| * param_source_rels are OK targets for parameterization of result paths |
| */ |
| typedef struct JoinPathExtraData |
| { |
| List *restrictlist; |
| List *mergeclause_list; |
| bool inner_unique; |
| SpecialJoinInfo *sjinfo; |
| SemiAntiJoinFactors semifactors; |
| Relids param_source_rels; |
| } JoinPathExtraData; |
| |
| /* |
| * Various flags indicating what kinds of grouping are possible. |
| * |
| * GROUPING_CAN_USE_SORT should be set if it's possible to perform |
| * sort-based implementations of grouping. When grouping sets are in use, |
| * this will be true if sorting is potentially usable for any of the grouping |
| * sets, even if it's not usable for all of them. |
| * |
| * GROUPING_CAN_USE_HASH should be set if it's possible to perform |
| * hash-based implementations of grouping. |
| * |
| * GROUPING_CAN_PARTIAL_AGG should be set if the aggregation is of a type |
| * for which we support partial aggregation (not, for example, grouping sets). |
| * It says nothing about parallel-safety or the availability of suitable paths. |
| */ |
| #define GROUPING_CAN_USE_SORT 0x0001 |
| #define GROUPING_CAN_USE_HASH 0x0002 |
| #define GROUPING_CAN_PARTIAL_AGG 0x0004 |
| |
| /* |
| * What kind of partitionwise aggregation is in use? |
| * |
| * PARTITIONWISE_AGGREGATE_NONE: Not used. |
| * |
| * PARTITIONWISE_AGGREGATE_FULL: Aggregate each partition separately, and |
| * append the results. |
| * |
| * PARTITIONWISE_AGGREGATE_PARTIAL: Partially aggregate each partition |
| * separately, append the results, and then finalize aggregation. |
| */ |
| typedef enum |
| { |
| PARTITIONWISE_AGGREGATE_NONE, |
| PARTITIONWISE_AGGREGATE_FULL, |
| PARTITIONWISE_AGGREGATE_PARTIAL |
| } PartitionwiseAggregateType; |
| |
| /* |
| * Struct for extra information passed to subroutines of create_grouping_paths |
| * |
| * flags indicating what kinds of grouping are possible. |
| * partial_costs_set is true if the agg_partial_costs and agg_final_costs |
| * have been initialized. |
| * agg_partial_costs gives partial aggregation costs. |
| * agg_final_costs gives finalization costs. |
| * target_parallel_safe is true if target is parallel safe. |
| * havingQual gives list of quals to be applied after aggregation. |
| * targetList gives list of columns to be projected. |
| * patype is the type of partitionwise aggregation that is being performed. |
| */ |
| typedef struct |
| { |
| /* Data which remains constant once set. */ |
| int flags; |
| bool partial_costs_set; |
| AggClauseCosts agg_partial_costs; |
| AggClauseCosts agg_final_costs; |
| |
| /* Data which may differ across partitions. */ |
| bool target_parallel_safe; |
| Node *havingQual; |
| List *targetList; |
| PartitionwiseAggregateType patype; |
| } GroupPathExtraData; |
| |
| /* |
| * Struct for extra information passed to subroutines of grouping_planner |
| * |
| * limit_needed is true if we actually need a Limit plan node. |
| * limit_tuples is an estimated bound on the number of output tuples, |
| * or -1 if no LIMIT or couldn't estimate. |
| * count_est and offset_est are the estimated values of the LIMIT and OFFSET |
| * expressions computed by preprocess_limit() (see comments for |
| * preprocess_limit() for more information). |
| */ |
| typedef struct |
| { |
| bool limit_needed; |
| double limit_tuples; |
| int64 count_est; |
| int64 offset_est; |
| } FinalPathExtraData; |
| |
| /* |
| * For speed reasons, cost estimation for join paths is performed in two |
| * phases: the first phase tries to quickly derive a lower bound for the |
| * join cost, and then we check if that's sufficient to reject the path. |
| * If not, we come back for a more refined cost estimate. The first phase |
| * fills a JoinCostWorkspace struct with its preliminary cost estimates |
| * and possibly additional intermediate values. The second phase takes |
| * these values as inputs to avoid repeating work. |
| * |
| * (Ideally we'd declare this in cost.h, but it's also needed in pathnode.h, |
| * so seems best to put it here.) |
| */ |
| typedef struct JoinCostWorkspace |
| { |
| /* Preliminary cost estimates --- must not be larger than final ones! */ |
| Cost startup_cost; /* cost expended before fetching any tuples */ |
| Cost total_cost; /* total cost (assuming all tuples fetched) */ |
| |
| /* Fields below here should be treated as private to costsize.c */ |
| Cost run_cost; /* non-startup cost components */ |
| |
| /* private for cost_nestloop code */ |
| Cost inner_run_cost; /* also used by cost_mergejoin code */ |
| Cost inner_rescan_run_cost; |
| |
| /* private for cost_mergejoin code */ |
| double outer_rows; |
| double inner_rows; |
| double outer_skip_rows; |
| double inner_skip_rows; |
| |
| /* private for cost_hashjoin code */ |
| int numbuckets; |
| int numbatches; |
| double inner_rows_total; |
| } JoinCostWorkspace; |
| |
| #endif /* PATHNODES_H */ |