text: /*-------------------------------------------------------------------------
   *
   * cost.h
   *	  prototypes for costsize.c and clausesel.c.
   *
   *
   * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
   * Portions Copyright (c) 1994, Regents of the University of California
   *
   * src/include/optimizer/cost.h
   *
   *-------------------------------------------------------------------------
   */
  #ifndef COST_H
  #define COST_H
  
  #include "nodes/pathnodes.h"
  #include "nodes/plannodes.h"
  
  
  /* defaults for costsize.c's Cost parameters */
  /* NB: cost-estimation code should use the variables, not these constants! */
  /* If you change these, update backend/utils/misc/postgresql.conf.sample */
  #define DEFAULT_SEQ_PAGE_COST  1.0
  #define DEFAULT_RANDOM_PAGE_COST  4.0
  #define DEFAULT_CPU_TUPLE_COST	0.01
  #define DEFAULT_CPU_INDEX_TUPLE_COST 0.005
  #define DEFAULT_CPU_OPERATOR_COST  0.0025
  #define DEFAULT_PARALLEL_TUPLE_COST 0.1
  #define DEFAULT_PARALLEL_SETUP_COST  1000.0
  
  #define DEFAULT_EFFECTIVE_CACHE_SIZE  524288	/* measured in pages */
  
  typedef enum
  {
  	CONSTRAINT_EXCLUSION_OFF,	/* do not use c_e */
  	CONSTRAINT_EXCLUSION_ON,	/* apply c_e to all rels */
  	CONSTRAINT_EXCLUSION_PARTITION	/* apply c_e to otherrels only */
  }			ConstraintExclusionType;
  
  
  /*
   * prototypes for costsize.c
   *	  routines to compute costs and sizes
   */
  
  /* parameter variables and flags (see also optimizer.h) */
  extern PGDLLIMPORT Cost disable_cost;
  extern PGDLLIMPORT int max_parallel_workers_per_gather;
  extern PGDLLIMPORT bool enable_seqscan;
  extern PGDLLIMPORT bool enable_indexscan;
  extern PGDLLIMPORT bool enable_indexonlyscan;
  extern PGDLLIMPORT bool enable_bitmapscan;
  extern PGDLLIMPORT bool enable_tidscan;
  extern PGDLLIMPORT bool enable_sort;
  extern PGDLLIMPORT bool enable_incremental_sort;
  extern PGDLLIMPORT bool enable_hashagg;
  extern PGDLLIMPORT bool enable_nestloop;
  extern PGDLLIMPORT bool enable_material;
  extern PGDLLIMPORT bool enable_memoize;
  extern PGDLLIMPORT bool enable_mergejoin;
  extern PGDLLIMPORT bool enable_hashjoin;
  extern PGDLLIMPORT bool enable_gathermerge;
  extern PGDLLIMPORT bool enable_partitionwise_join;
  extern PGDLLIMPORT bool enable_partitionwise_aggregate;
  extern PGDLLIMPORT bool enable_parallel_append;
  extern PGDLLIMPORT bool enable_parallel_hash;
  extern PGDLLIMPORT bool enable_partition_pruning;
  extern PGDLLIMPORT bool enable_async_append;
  extern PGDLLIMPORT int constraint_exclusion;
  
  extern double index_pages_fetched(double tuples_fetched, BlockNumber pages,
  								  double index_pages, PlannerInfo *root);
  extern void cost_seqscan(Path *path, PlannerInfo *root, RelOptInfo *baserel,
  						 ParamPathInfo *param_info);
  extern void cost_samplescan(Path *path, PlannerInfo *root, RelOptInfo *baserel,
  							ParamPathInfo *param_info);
  extern void cost_index(IndexPath *path, PlannerInfo *root,
  					   double loop_count, bool partial_path);
  extern void cost_bitmap_heap_scan(Path *path, PlannerInfo *root, RelOptInfo *baserel,
  								  ParamPathInfo *param_info,
  								  Path *bitmapqual, double loop_count);
  extern void cost_bitmap_and_node(BitmapAndPath *path, PlannerInfo *root);
  extern void cost_bitmap_or_node(BitmapOrPath *path, PlannerInfo *root);
  extern void cost_bitmap_tree_node(Path *path, Cost *cost, Selectivity *selec);
  extern void cost_tidscan(Path *path, PlannerInfo *root,
  						 RelOptInfo *baserel, List *tidquals, ParamPathInfo *param_info);
  extern void cost_tidrangescan(Path *path, PlannerInfo *root,
  							  RelOptInfo *baserel, List *tidrangequals,
  							  ParamPathInfo *param_info);
  extern void cost_subqueryscan(SubqueryScanPath *path, PlannerInfo *root,
  							  RelOptInfo *baserel, ParamPathInfo *param_info);
  extern void cost_functionscan(Path *path, PlannerInfo *root,
  							  RelOptInfo *baserel, ParamPathInfo *param_info);
  extern void cost_valuesscan(Path *path, PlannerInfo *root,
  							RelOptInfo *baserel, ParamPathInfo *param_info);
  extern void cost_tablefuncscan(Path *path, PlannerInfo *root,
  							   RelOptInfo *baserel, ParamPathInfo *param_info);
  extern void cost_ctescan(Path *path, PlannerInfo *root,
  						 RelOptInfo *baserel, ParamPathInfo *param_info);
  extern void cost_namedtuplestorescan(Path *path, PlannerInfo *root,
  									 RelOptInfo *baserel, ParamPathInfo *param_info);
  extern void cost_resultscan(Path *path, PlannerInfo *root,
  							RelOptInfo *baserel, ParamPathInfo *param_info);
  extern void cost_recursive_union(Path *runion, Path *nrterm, Path *rterm);
  extern void cost_sort(Path *path, PlannerInfo *root,
  					  List *pathkeys, Cost input_cost, double tuples, int width,
  					  Cost comparison_cost, int sort_mem,
  					  double limit_tuples);
  extern void cost_incremental_sort(Path *path,
  								  PlannerInfo *root, List *pathkeys, int presorted_keys,
  								  Cost input_startup_cost, Cost input_total_cost,
  								  double input_tuples, int width, Cost comparison_cost, int sort_mem,
  								  double limit_tuples);
  extern void cost_append(AppendPath *path);
  extern void cost_merge_append(Path *path, PlannerInfo *root,
  							  List *pathkeys, int n_streams,
  							  Cost input_startup_cost, Cost input_total_cost,
  							  double tuples);
  extern void cost_material(Path *path,
  						  Cost input_startup_cost, Cost input_total_cost,
  						  double tuples, int width);
  extern void cost_agg(Path *path, PlannerInfo *root,
  					 AggStrategy aggstrategy, const AggClauseCosts *aggcosts,
  					 int numGroupCols, double numGroups,
  					 List *quals,
  					 Cost input_startup_cost, Cost input_total_cost,
  					 double input_tuples, double input_width);
  extern void cost_windowagg(Path *path, PlannerInfo *root,
  						   List *windowFuncs, int numPartCols, int numOrderCols,
  						   Cost input_startup_cost, Cost input_total_cost,
  						   double input_tuples);
  extern void cost_group(Path *path, PlannerInfo *root,
  					   int numGroupCols, double numGroups,
  					   List *quals,
  					   Cost input_startup_cost, Cost input_total_cost,
  					   double input_tuples);
  extern void initial_cost_nestloop(PlannerInfo *root,
  								  JoinCostWorkspace *workspace,
  								  JoinType jointype,
  								  Path *outer_path, Path *inner_path,
  								  JoinPathExtraData *extra);
  extern void final_cost_nestloop(PlannerInfo *root, NestPath *path,
  								JoinCostWorkspace *workspace,
  								JoinPathExtraData *extra);
  extern void initial_cost_mergejoin(PlannerInfo *root,
  								   JoinCostWorkspace *workspace,
  								   JoinType jointype,
  								   List *mergeclauses,
  								   Path *outer_path, Path *inner_path,
  								   List *outersortkeys, List *innersortkeys,
  								   JoinPathExtraData *extra);
  extern void final_cost_mergejoin(PlannerInfo *root, MergePath *path,
  								 JoinCostWorkspace *workspace,
  								 JoinPathExtraData *extra);
  extern void initial_cost_hashjoin(PlannerInfo *root,
  								  JoinCostWorkspace *workspace,
  								  JoinType jointype,
  								  List *hashclauses,
  								  Path *outer_path, Path *inner_path,
  								  JoinPathExtraData *extra,
  								  bool parallel_hash);
  extern void final_cost_hashjoin(PlannerInfo *root, HashPath *path,
  								JoinCostWorkspace *workspace,
  								JoinPathExtraData *extra);
  extern void cost_gather(GatherPath *path, PlannerInfo *root,
  						RelOptInfo *baserel, ParamPathInfo *param_info, double *rows);
  extern void cost_gather_merge(GatherMergePath *path, PlannerInfo *root,
  							  RelOptInfo *rel, ParamPathInfo *param_info,
  							  Cost input_startup_cost, Cost input_total_cost,
  							  double *rows);
  extern void cost_subplan(PlannerInfo *root, SubPlan *subplan, Plan *plan);
  extern void cost_qual_eval(QualCost *cost, List *quals, PlannerInfo *root);
  extern void cost_qual_eval_node(QualCost *cost, Node *qual, PlannerInfo *root);
  extern void compute_semi_anti_join_factors(PlannerInfo *root,
  										   RelOptInfo *joinrel,
  										   RelOptInfo *outerrel,
  										   RelOptInfo *innerrel,
  										   JoinType jointype,
  										   SpecialJoinInfo *sjinfo,
  										   List *restrictlist,
  										   SemiAntiJoinFactors *semifactors);
  extern void set_baserel_size_estimates(PlannerInfo *root, RelOptInfo *rel);
  extern double get_parameterized_baserel_size(PlannerInfo *root,
  											 RelOptInfo *rel,
  											 List *param_clauses);
  extern double get_parameterized_joinrel_size(PlannerInfo *root,
  											 RelOptInfo *rel,
  											 Path *outer_path,
  											 Path *inner_path,
  											 SpecialJoinInfo *sjinfo,
  											 List *restrict_clauses);
  extern void set_joinrel_size_estimates(PlannerInfo *root, RelOptInfo *rel,
  									   RelOptInfo *outer_rel,
  									   RelOptInfo *inner_rel,
  									   SpecialJoinInfo *sjinfo,
  									   List *restrictlist);
  extern void set_subquery_size_estimates(PlannerInfo *root, RelOptInfo *rel);
  extern void set_function_size_estimates(PlannerInfo *root, RelOptInfo *rel);
  extern void set_values_size_estimates(PlannerInfo *root, RelOptInfo *rel);
  extern void set_cte_size_estimates(PlannerInfo *root, RelOptInfo *rel,
  								   double cte_rows);
  extern void set_tablefunc_size_estimates(PlannerInfo *root, RelOptInfo *rel);
  extern void set_namedtuplestore_size_estimates(PlannerInfo *root, RelOptInfo *rel);
  extern void set_result_size_estimates(PlannerInfo *root, RelOptInfo *rel);
  extern void set_foreign_size_estimates(PlannerInfo *root, RelOptInfo *rel);
  extern PathTarget *set_pathtarget_cost_width(PlannerInfo *root, PathTarget *target);
  extern double compute_bitmap_pages(PlannerInfo *root, RelOptInfo *baserel,
  								   Path *bitmapqual, int loop_count, Cost *cost, double *tuple);
  
  #endif							/* COST_H */
  