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d69d01ba9d
A couple of places weren't up to speed for this. By sheer good luck, we didn't fail but just selected a non-memoized join plan, at least in the test case we have. Nonetheless, it's a bug, and I'm not quite sure that it couldn't have worse consequences in other examples. So back-patch to v14 where Memoize came in. Richard Guo Discussion: https://postgr.es/m/CAMbWs48GkNom272sfp0-WeD6_0HSR19BJ4H1c9ZKSfbVnJsvRg@mail.gmail.com
3221 lines
121 KiB
C
3221 lines
121 KiB
C
/*-------------------------------------------------------------------------
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*
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* pathnodes.h
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* Definitions for planner's internal data structures, especially Paths.
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*
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* We don't support copying RelOptInfo, IndexOptInfo, or Path nodes.
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* There are some subsidiary structs that are useful to copy, though.
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*
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* Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/nodes/pathnodes.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef PATHNODES_H
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#define PATHNODES_H
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#include "access/sdir.h"
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#include "lib/stringinfo.h"
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#include "nodes/params.h"
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#include "nodes/parsenodes.h"
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#include "storage/block.h"
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/*
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* Relids
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* Set of relation identifiers (indexes into the rangetable).
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*/
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typedef Bitmapset *Relids;
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/*
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* When looking for a "cheapest path", this enum specifies whether we want
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* cheapest startup cost or cheapest total cost.
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*/
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typedef enum CostSelector
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{
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STARTUP_COST, TOTAL_COST
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} CostSelector;
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/*
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* The cost estimate produced by cost_qual_eval() includes both a one-time
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* (startup) cost, and a per-tuple cost.
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*/
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typedef struct QualCost
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{
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Cost startup; /* one-time cost */
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Cost per_tuple; /* per-evaluation cost */
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} QualCost;
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/*
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* Costing aggregate function execution requires these statistics about
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* the aggregates to be executed by a given Agg node. Note that the costs
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* include the execution costs of the aggregates' argument expressions as
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* well as the aggregate functions themselves. Also, the fields must be
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* defined so that initializing the struct to zeroes with memset is correct.
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*/
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typedef struct AggClauseCosts
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{
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QualCost transCost; /* total per-input-row execution costs */
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QualCost finalCost; /* total per-aggregated-row costs */
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Size transitionSpace; /* space for pass-by-ref transition data */
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} AggClauseCosts;
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/*
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* This enum identifies the different types of "upper" (post-scan/join)
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* relations that we might deal with during planning.
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*/
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typedef enum UpperRelationKind
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{
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UPPERREL_SETOP, /* result of UNION/INTERSECT/EXCEPT, if any */
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UPPERREL_PARTIAL_GROUP_AGG, /* result of partial grouping/aggregation, if
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* any */
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UPPERREL_GROUP_AGG, /* result of grouping/aggregation, if any */
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UPPERREL_WINDOW, /* result of window functions, if any */
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UPPERREL_PARTIAL_DISTINCT, /* result of partial "SELECT DISTINCT", if any */
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UPPERREL_DISTINCT, /* result of "SELECT DISTINCT", if any */
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UPPERREL_ORDERED, /* result of ORDER BY, if any */
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UPPERREL_FINAL /* result of any remaining top-level actions */
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/* NB: UPPERREL_FINAL must be last enum entry; it's used to size arrays */
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} UpperRelationKind;
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/*----------
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* PlannerGlobal
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* Global information for planning/optimization
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*
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* PlannerGlobal holds state for an entire planner invocation; this state
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* is shared across all levels of sub-Queries that exist in the command being
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* planned.
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*
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* Not all fields are printed. (In some cases, there is no print support for
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* the field type; in others, doing so would lead to infinite recursion.)
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*----------
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*/
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typedef struct PlannerGlobal
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{
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pg_node_attr(no_copy_equal, no_read)
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NodeTag type;
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/* Param values provided to planner() */
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ParamListInfo boundParams pg_node_attr(read_write_ignore);
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/* Plans for SubPlan nodes */
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List *subplans;
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/* PlannerInfos for SubPlan nodes */
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List *subroots pg_node_attr(read_write_ignore);
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/* indices of subplans that require REWIND */
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Bitmapset *rewindPlanIDs;
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/* "flat" rangetable for executor */
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List *finalrtable;
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/* "flat" list of PlanRowMarks */
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List *finalrowmarks;
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/* "flat" list of integer RT indexes */
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List *resultRelations;
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/* "flat" list of AppendRelInfos */
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List *appendRelations;
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/* List of PartitionPruneInfo contained in the plan */
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List *partPruneInfos;
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/* OIDs of relations the plan depends on */
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List *relationOids;
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/* other dependencies, as PlanInvalItems */
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List *invalItems;
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/* type OIDs for PARAM_EXEC Params */
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List *paramExecTypes;
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/* highest PlaceHolderVar ID assigned */
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Index lastPHId;
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/* highest PlanRowMark ID assigned */
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Index lastRowMarkId;
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/* highest plan node ID assigned */
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int lastPlanNodeId;
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/* redo plan when TransactionXmin changes? */
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bool transientPlan;
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/* is plan specific to current role? */
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bool dependsOnRole;
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/* parallel mode potentially OK? */
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bool parallelModeOK;
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/* parallel mode actually required? */
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bool parallelModeNeeded;
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/* worst PROPARALLEL hazard level */
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char maxParallelHazard;
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/* partition descriptors */
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PartitionDirectory partition_directory pg_node_attr(read_write_ignore);
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} PlannerGlobal;
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/* macro for fetching the Plan associated with a SubPlan node */
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#define planner_subplan_get_plan(root, subplan) \
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((Plan *) list_nth((root)->glob->subplans, (subplan)->plan_id - 1))
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/*----------
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* PlannerInfo
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* Per-query information for planning/optimization
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*
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* This struct is conventionally called "root" in all the planner routines.
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* It holds links to all of the planner's working state, in addition to the
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* original Query. Note that at present the planner extensively modifies
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* the passed-in Query data structure; someday that should stop.
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*
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* For reasons explained in optimizer/optimizer.h, we define the typedef
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* either here or in that header, whichever is read first.
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*
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* Not all fields are printed. (In some cases, there is no print support for
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* the field type; in others, doing so would lead to infinite recursion or
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* bloat dump output more than seems useful.)
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*----------
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*/
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#ifndef HAVE_PLANNERINFO_TYPEDEF
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typedef struct PlannerInfo PlannerInfo;
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#define HAVE_PLANNERINFO_TYPEDEF 1
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#endif
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struct PlannerInfo
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{
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pg_node_attr(no_copy_equal, no_read)
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NodeTag type;
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/* the Query being planned */
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Query *parse;
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/* global info for current planner run */
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PlannerGlobal *glob;
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/* 1 at the outermost Query */
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Index query_level;
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/* NULL at outermost Query */
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PlannerInfo *parent_root pg_node_attr(read_write_ignore);
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/*
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* plan_params contains the expressions that this query level needs to
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* make available to a lower query level that is currently being planned.
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* outer_params contains the paramIds of PARAM_EXEC Params that outer
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* query levels will make available to this query level.
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*/
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/* list of PlannerParamItems, see below */
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List *plan_params;
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Bitmapset *outer_params;
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/*
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* simple_rel_array holds pointers to "base rels" and "other rels" (see
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* comments for RelOptInfo for more info). It is indexed by rangetable
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* index (so entry 0 is always wasted). Entries can be NULL when an RTE
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* does not correspond to a base relation, such as a join RTE or an
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* unreferenced view RTE; or if the RelOptInfo hasn't been made yet.
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*/
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struct RelOptInfo **simple_rel_array pg_node_attr(array_size(simple_rel_array_size));
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/* allocated size of array */
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int simple_rel_array_size;
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/*
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* simple_rte_array is the same length as simple_rel_array and holds
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* pointers to the associated rangetable entries. Using this is a shade
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* faster than using rt_fetch(), mostly due to fewer indirections. (Not
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* printed because it'd be redundant with parse->rtable.)
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*/
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RangeTblEntry **simple_rte_array pg_node_attr(read_write_ignore);
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/*
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* append_rel_array is the same length as the above arrays, and holds
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* pointers to the corresponding AppendRelInfo entry indexed by
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* child_relid, or NULL if the rel is not an appendrel child. The array
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* itself is not allocated if append_rel_list is empty. (Not printed
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* because it'd be redundant with append_rel_list.)
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*/
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struct AppendRelInfo **append_rel_array pg_node_attr(read_write_ignore);
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/*
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* all_baserels is a Relids set of all base relids (but not "other"
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* relids) in the query; that is, the Relids identifier of the final join
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* we need to form. This is computed in make_one_rel, just before we
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* start making Paths.
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*/
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Relids all_baserels;
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/*
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* nullable_baserels is a Relids set of base relids that are nullable by
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* some outer join in the jointree; these are rels that are potentially
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* nullable below the WHERE clause, SELECT targetlist, etc. This is
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* computed in deconstruct_jointree.
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*/
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Relids nullable_baserels;
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/*
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* join_rel_list is a list of all join-relation RelOptInfos we have
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* considered in this planning run. For small problems we just scan the
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* list to do lookups, but when there are many join relations we build a
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* hash table for faster lookups. The hash table is present and valid
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* when join_rel_hash is not NULL. Note that we still maintain the list
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* even when using the hash table for lookups; this simplifies life for
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* GEQO.
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*/
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List *join_rel_list;
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struct HTAB *join_rel_hash pg_node_attr(read_write_ignore);
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/*
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* When doing a dynamic-programming-style join search, join_rel_level[k]
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* is a list of all join-relation RelOptInfos of level k, and
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* join_cur_level is the current level. New join-relation RelOptInfos are
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* automatically added to the join_rel_level[join_cur_level] list.
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* join_rel_level is NULL if not in use.
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*
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* Note: we've already printed all baserel and joinrel RelOptInfos above,
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* so we don't dump join_rel_level or other lists of RelOptInfos.
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*/
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/* lists of join-relation RelOptInfos */
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List **join_rel_level pg_node_attr(read_write_ignore);
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/* index of list being extended */
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int join_cur_level;
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/* init SubPlans for query */
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List *init_plans;
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/*
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* per-CTE-item list of subplan IDs (or -1 if no subplan was made for that
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* CTE)
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*/
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List *cte_plan_ids;
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/* List of Lists of Params for MULTIEXPR subquery outputs */
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List *multiexpr_params;
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/* list of active EquivalenceClasses */
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List *eq_classes;
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/* set true once ECs are canonical */
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bool ec_merging_done;
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/* list of "canonical" PathKeys */
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List *canon_pathkeys;
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/*
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* list of RestrictInfos for mergejoinable outer join clauses
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* w/nonnullable var on left
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*/
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List *left_join_clauses;
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/*
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* list of RestrictInfos for mergejoinable outer join clauses
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* w/nonnullable var on right
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*/
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List *right_join_clauses;
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/*
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* list of RestrictInfos for mergejoinable full join clauses
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*/
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List *full_join_clauses;
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/* list of SpecialJoinInfos */
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List *join_info_list;
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/*
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* all_result_relids is empty for SELECT, otherwise it contains at least
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* parse->resultRelation. For UPDATE/DELETE/MERGE across an inheritance
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* or partitioning tree, the result rel's child relids are added. When
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* using multi-level partitioning, intermediate partitioned rels are
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* included. leaf_result_relids is similar except that only actual result
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* tables, not partitioned tables, are included in it.
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*/
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/* set of all result relids */
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Relids all_result_relids;
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/* set of all leaf relids */
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Relids leaf_result_relids;
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/*
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* list of AppendRelInfos
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*
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* Note: for AppendRelInfos describing partitions of a partitioned table,
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* we guarantee that partitions that come earlier in the partitioned
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* table's PartitionDesc will appear earlier in append_rel_list.
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*/
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List *append_rel_list;
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/* list of RowIdentityVarInfos */
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List *row_identity_vars;
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/* list of PlanRowMarks */
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List *rowMarks;
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/* list of PlaceHolderInfos */
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List *placeholder_list;
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/* array of PlaceHolderInfos indexed by phid */
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struct PlaceHolderInfo **placeholder_array pg_node_attr(read_write_ignore, array_size(placeholder_array_size));
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/* allocated size of array */
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int placeholder_array_size pg_node_attr(read_write_ignore);
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/* list of ForeignKeyOptInfos */
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List *fkey_list;
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/* desired pathkeys for query_planner() */
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List *query_pathkeys;
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/* groupClause pathkeys, if any */
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List *group_pathkeys;
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/*
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* The number of elements in the group_pathkeys list which belong to the
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* GROUP BY clause. Additional ones belong to ORDER BY / DISTINCT
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* aggregates.
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*/
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int num_groupby_pathkeys;
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/* pathkeys of bottom window, if any */
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List *window_pathkeys;
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/* distinctClause pathkeys, if any */
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List *distinct_pathkeys;
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/* sortClause pathkeys, if any */
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List *sort_pathkeys;
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/* Canonicalised partition schemes used in the query. */
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List *part_schemes pg_node_attr(read_write_ignore);
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/* RelOptInfos we are now trying to join */
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List *initial_rels pg_node_attr(read_write_ignore);
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/*
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* Upper-rel RelOptInfos. Use fetch_upper_rel() to get any particular
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* upper rel.
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*/
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List *upper_rels[UPPERREL_FINAL + 1] pg_node_attr(read_write_ignore);
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/* Result tlists chosen by grouping_planner for upper-stage processing */
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struct PathTarget *upper_targets[UPPERREL_FINAL + 1] pg_node_attr(read_write_ignore);
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/*
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* The fully-processed targetlist is kept here. It differs from
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* parse->targetList in that (for INSERT) it's been reordered to match the
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* target table, and defaults have been filled in. Also, additional
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* resjunk targets may be present. preprocess_targetlist() does most of
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* that work, but note that more resjunk targets can get added during
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* appendrel expansion. (Hence, upper_targets mustn't get set up till
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* after that.)
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*/
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List *processed_tlist;
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/*
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* For UPDATE, this list contains the target table's attribute numbers to
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* which the first N entries of processed_tlist are to be assigned. (Any
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* additional entries in processed_tlist must be resjunk.) DO NOT use the
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* resnos in processed_tlist to identify the UPDATE target columns.
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*/
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List *update_colnos;
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/*
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* Fields filled during create_plan() for use in setrefs.c
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*/
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/* for GroupingFunc fixup (can't print: array length not known here) */
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AttrNumber *grouping_map pg_node_attr(read_write_ignore);
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/* List of MinMaxAggInfos */
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List *minmax_aggs;
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/* context holding PlannerInfo */
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MemoryContext planner_cxt pg_node_attr(read_write_ignore);
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/* # of pages in all non-dummy tables of query */
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Cardinality total_table_pages;
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/* tuple_fraction passed to query_planner */
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Selectivity tuple_fraction;
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/* limit_tuples passed to query_planner */
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Cardinality limit_tuples;
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/*
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* Minimum security_level for quals. Note: qual_security_level is zero if
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* there are no securityQuals.
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*/
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Index qual_security_level;
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/* true if any RTEs are RTE_JOIN kind */
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bool hasJoinRTEs;
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/* true if any RTEs are marked LATERAL */
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bool hasLateralRTEs;
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/* true if havingQual was non-null */
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bool hasHavingQual;
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/* true if any RestrictInfo has pseudoconstant = true */
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bool hasPseudoConstantQuals;
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/* true if we've made any of those */
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bool hasAlternativeSubPlans;
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/* true once we're no longer allowed to add PlaceHolderInfos */
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bool placeholdersFrozen;
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/* true if planning a recursive WITH item */
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bool hasRecursion;
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/*
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* Information about aggregates. Filled by preprocess_aggrefs().
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*/
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/* AggInfo structs */
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List *agginfos;
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/* AggTransInfo structs */
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List *aggtransinfos;
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/* number of aggs with DISTINCT/ORDER BY/WITHIN GROUP */
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int numOrderedAggs;
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/* does any agg not support partial mode? */
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bool hasNonPartialAggs;
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/* is any partial agg non-serializable? */
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bool hasNonSerialAggs;
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/*
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* These fields are used only when hasRecursion is true:
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*/
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/* PARAM_EXEC ID for the work table */
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int wt_param_id;
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/* a path for non-recursive term */
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struct Path *non_recursive_path;
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/*
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* These fields are workspace for createplan.c
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*/
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/* outer rels above current node */
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Relids curOuterRels;
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/* not-yet-assigned NestLoopParams */
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List *curOuterParams;
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/*
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* These fields are workspace for setrefs.c. Each is an array
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* corresponding to glob->subplans. (We could probably teach
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* gen_node_support.pl how to determine the array length, but it doesn't
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* seem worth the trouble, so just mark them read_write_ignore.)
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*/
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bool *isAltSubplan pg_node_attr(read_write_ignore);
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bool *isUsedSubplan pg_node_attr(read_write_ignore);
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/* optional private data for join_search_hook, e.g., GEQO */
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void *join_search_private pg_node_attr(read_write_ignore);
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/* Does this query modify any partition key columns? */
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bool partColsUpdated;
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|
|
/* PartitionPruneInfos added in this query's plan. */
|
|
List *partPruneInfos;
|
|
};
|
|
|
|
|
|
/*
|
|
* 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
|
|
*
|
|
* The partexprs and nullable_partexprs arrays each contain
|
|
* part_scheme->partnatts elements. Each of the elements is a list of
|
|
* partition key expressions. For partitioned base relations, there is one
|
|
* expression in each partexprs element, and nullable_partexprs is empty.
|
|
* For partitioned join relations, each base relation within the join
|
|
* contributes one partition key expression per partitioning column;
|
|
* that expression goes in the partexprs[i] list if the base relation
|
|
* is not nullable by this join or any lower outer join, or in the
|
|
* nullable_partexprs[i] list if the base relation is nullable.
|
|
* Furthermore, FULL JOINs add extra nullable_partexprs expressions
|
|
* corresponding to COALESCE expressions of the left and right join columns,
|
|
* to simplify matching join clauses to those lists.
|
|
*
|
|
* Not all fields are printed. (In some cases, there is no print support for
|
|
* the field type.)
|
|
*----------
|
|
*/
|
|
|
|
/* Bitmask of flags supported by table AMs */
|
|
#define AMFLAG_HAS_TID_RANGE (1 << 0)
|
|
|
|
typedef enum RelOptKind
|
|
{
|
|
RELOPT_BASEREL,
|
|
RELOPT_JOINREL,
|
|
RELOPT_OTHER_MEMBER_REL,
|
|
RELOPT_OTHER_JOINREL,
|
|
RELOPT_UPPER_REL,
|
|
RELOPT_OTHER_UPPER_REL,
|
|
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
|
|
{
|
|
pg_node_attr(no_copy_equal, no_read)
|
|
|
|
NodeTag type;
|
|
|
|
RelOptKind reloptkind;
|
|
|
|
/*
|
|
* all relations included in this RelOptInfo; set of base relids
|
|
* (rangetable indexes)
|
|
*/
|
|
Relids relids;
|
|
|
|
/*
|
|
* size estimates generated by planner
|
|
*/
|
|
/* estimated number of result tuples */
|
|
Cardinality rows;
|
|
|
|
/*
|
|
* per-relation planner control flags
|
|
*/
|
|
/* keep cheap-startup-cost paths? */
|
|
bool consider_startup;
|
|
/* ditto, for parameterized paths? */
|
|
bool consider_param_startup;
|
|
/* consider parallel paths? */
|
|
bool consider_parallel;
|
|
|
|
/*
|
|
* default result targetlist for Paths scanning this relation; list of
|
|
* Vars/Exprs, cost, width
|
|
*/
|
|
struct PathTarget *reltarget;
|
|
|
|
/*
|
|
* materialization information
|
|
*/
|
|
List *pathlist; /* Path structures */
|
|
List *ppilist; /* ParamPathInfos used in pathlist */
|
|
List *partial_pathlist; /* partial Paths */
|
|
struct Path *cheapest_startup_path;
|
|
struct Path *cheapest_total_path;
|
|
struct Path *cheapest_unique_path;
|
|
List *cheapest_parameterized_paths;
|
|
|
|
/*
|
|
* parameterization information needed for both base rels and join rels
|
|
* (see also lateral_vars and lateral_referencers)
|
|
*/
|
|
/* rels directly laterally referenced */
|
|
Relids direct_lateral_relids;
|
|
/* minimum parameterization of rel */
|
|
Relids lateral_relids;
|
|
|
|
/*
|
|
* information about a base rel (not set for join rels!)
|
|
*/
|
|
Index relid;
|
|
/* containing tablespace */
|
|
Oid reltablespace;
|
|
/* RELATION, SUBQUERY, FUNCTION, etc */
|
|
RTEKind rtekind;
|
|
/* smallest attrno of rel (often <0) */
|
|
AttrNumber min_attr;
|
|
/* largest attrno of rel */
|
|
AttrNumber max_attr;
|
|
/* array indexed [min_attr .. max_attr] */
|
|
Relids *attr_needed pg_node_attr(read_write_ignore);
|
|
/* array indexed [min_attr .. max_attr] */
|
|
int32 *attr_widths pg_node_attr(read_write_ignore);
|
|
/* LATERAL Vars and PHVs referenced by rel */
|
|
List *lateral_vars;
|
|
/* rels that reference me laterally */
|
|
Relids lateral_referencers;
|
|
/* list of IndexOptInfo */
|
|
List *indexlist;
|
|
/* list of StatisticExtInfo */
|
|
List *statlist;
|
|
/* size estimates derived from pg_class */
|
|
BlockNumber pages;
|
|
Cardinality tuples;
|
|
double allvisfrac;
|
|
|
|
/*
|
|
* Indexes in PlannerInfo's eq_classes list of ECs that mention this rel
|
|
*/
|
|
Bitmapset *eclass_indexes;
|
|
PlannerInfo *subroot; /* if subquery */
|
|
List *subplan_params; /* if subquery */
|
|
/* wanted number of parallel workers */
|
|
int rel_parallel_workers;
|
|
/* Bitmask of optional features supported by the table AM */
|
|
uint32 amflags;
|
|
|
|
/*
|
|
* Information about foreign tables and foreign joins
|
|
*/
|
|
/* identifies server for the table or join */
|
|
Oid serverid;
|
|
/* identifies user to check access as; 0 means to check as current user */
|
|
Oid userid;
|
|
/* join is only valid for current user */
|
|
bool useridiscurrent;
|
|
/* use "struct FdwRoutine" to avoid including fdwapi.h here */
|
|
struct FdwRoutine *fdwroutine pg_node_attr(read_write_ignore);
|
|
void *fdw_private pg_node_attr(read_write_ignore);
|
|
|
|
/*
|
|
* cache space for remembering if we have proven this relation unique
|
|
*/
|
|
/* known unique for these other relid set(s) */
|
|
List *unique_for_rels;
|
|
/* known not unique for these set(s) */
|
|
List *non_unique_for_rels;
|
|
|
|
/*
|
|
* used by various scans and joins:
|
|
*/
|
|
/* RestrictInfo structures (if base rel) */
|
|
List *baserestrictinfo;
|
|
/* cost of evaluating the above */
|
|
QualCost baserestrictcost;
|
|
/* min security_level found in baserestrictinfo */
|
|
Index baserestrict_min_security;
|
|
/* RestrictInfo structures for join clauses involving this rel */
|
|
List *joininfo;
|
|
/* T means joininfo is incomplete */
|
|
bool has_eclass_joins;
|
|
|
|
/*
|
|
* used by partitionwise joins:
|
|
*/
|
|
/* consider partitionwise join paths? (if partitioned rel) */
|
|
bool consider_partitionwise_join;
|
|
|
|
/*
|
|
* inheritance links, if this is an otherrel (otherwise NULL):
|
|
*/
|
|
/* Immediate parent relation (dumping it would be too verbose) */
|
|
struct RelOptInfo *parent pg_node_attr(read_write_ignore);
|
|
/* Topmost parent relation (dumping it would be too verbose) */
|
|
struct RelOptInfo *top_parent pg_node_attr(read_write_ignore);
|
|
/* Relids of topmost parent (redundant, but handy) */
|
|
Relids top_parent_relids;
|
|
|
|
/*
|
|
* used for partitioned relations:
|
|
*/
|
|
/* Partitioning scheme */
|
|
PartitionScheme part_scheme pg_node_attr(read_write_ignore);
|
|
|
|
/*
|
|
* Number of partitions; -1 if not yet set; in case of a join relation 0
|
|
* means it's considered unpartitioned
|
|
*/
|
|
int nparts;
|
|
/* Partition bounds */
|
|
struct PartitionBoundInfoData *boundinfo pg_node_attr(read_write_ignore);
|
|
/* True if partition bounds were created by partition_bounds_merge() */
|
|
bool partbounds_merged;
|
|
/* Partition constraint, if not the root */
|
|
List *partition_qual;
|
|
|
|
/*
|
|
* Array of RelOptInfos of partitions, stored in the same order as bounds
|
|
* (don't print, too bulky and duplicative)
|
|
*/
|
|
struct RelOptInfo **part_rels pg_node_attr(read_write_ignore);
|
|
|
|
/*
|
|
* Bitmap with members acting as indexes into the part_rels[] array to
|
|
* indicate which partitions survived partition pruning.
|
|
*/
|
|
Bitmapset *live_parts;
|
|
/* Relids set of all partition relids */
|
|
Relids all_partrels;
|
|
|
|
/*
|
|
* These arrays are of length partkey->partnatts, which we don't have at
|
|
* hand, so don't try to print
|
|
*/
|
|
|
|
/* Non-nullable partition key expressions */
|
|
List **partexprs pg_node_attr(read_write_ignore);
|
|
/* Nullable partition key expressions */
|
|
List **nullable_partexprs pg_node_attr(read_write_ignore);
|
|
} RelOptInfo;
|
|
|
|
/*
|
|
* Is given relation partitioned?
|
|
*
|
|
* It's not enough to test whether rel->part_scheme is set, because it might
|
|
* be that the basic partitioning properties of the input relations matched
|
|
* but the partition bounds did not. Also, if we are able to prove a rel
|
|
* dummy (empty), we should henceforth treat it as unpartitioned.
|
|
*/
|
|
#define IS_PARTITIONED_REL(rel) \
|
|
((rel)->part_scheme && (rel)->boundinfo && (rel)->nparts > 0 && \
|
|
(rel)->part_rels && !IS_DUMMY_REL(rel))
|
|
|
|
/*
|
|
* Convenience macro to make sure that a partitioned relation has all the
|
|
* required members set.
|
|
*/
|
|
#define REL_HAS_ALL_PART_PROPS(rel) \
|
|
((rel)->part_scheme && (rel)->boundinfo && (rel)->nparts > 0 && \
|
|
(rel)->part_rels && (rel)->partexprs && (rel)->nullable_partexprs)
|
|
|
|
/*
|
|
* IndexOptInfo
|
|
* Per-index information for planning/optimization
|
|
*
|
|
* indexkeys[], indexcollations[] each have ncolumns entries.
|
|
* opfamily[], and opcintype[] each have nkeycolumns entries. They do
|
|
* not contain any information about included attributes.
|
|
*
|
|
* sortopfamily[], reverse_sort[], and nulls_first[] have
|
|
* nkeycolumns entries, if the index is ordered; but if it is unordered,
|
|
* those pointers are NULL.
|
|
*
|
|
* Zeroes in the indexkeys[] array indicate index columns that are
|
|
* expressions; there is one element in indexprs for each such column.
|
|
*
|
|
* For an ordered index, reverse_sort[] and nulls_first[] describe the
|
|
* sort ordering of a forward indexscan; we can also consider a backward
|
|
* indexscan, which will generate the reverse ordering.
|
|
*
|
|
* The indexprs and indpred expressions have been run through
|
|
* prepqual.c and eval_const_expressions() for ease of matching to
|
|
* WHERE clauses. indpred is in implicit-AND form.
|
|
*
|
|
* indextlist is a TargetEntry list representing the index columns.
|
|
* It provides an equivalent base-relation Var for each simple column,
|
|
* and links to the matching indexprs element for each expression column.
|
|
*
|
|
* While most of these fields are filled when the IndexOptInfo is created
|
|
* (by plancat.c), indrestrictinfo and predOK are set later, in
|
|
* check_index_predicates().
|
|
*/
|
|
#ifndef HAVE_INDEXOPTINFO_TYPEDEF
|
|
typedef struct IndexOptInfo IndexOptInfo;
|
|
#define HAVE_INDEXOPTINFO_TYPEDEF 1
|
|
#endif
|
|
|
|
struct IndexOptInfo
|
|
{
|
|
pg_node_attr(no_copy_equal, no_read)
|
|
|
|
NodeTag type;
|
|
|
|
/* OID of the index relation */
|
|
Oid indexoid;
|
|
/* tablespace of index (not table) */
|
|
Oid reltablespace;
|
|
/* back-link to index's table; don't print, else infinite recursion */
|
|
RelOptInfo *rel pg_node_attr(read_write_ignore);
|
|
|
|
/*
|
|
* index-size statistics (from pg_class and elsewhere)
|
|
*/
|
|
/* number of disk pages in index */
|
|
BlockNumber pages;
|
|
/* number of index tuples in index */
|
|
Cardinality tuples;
|
|
/* index tree height, or -1 if unknown */
|
|
int tree_height;
|
|
|
|
/*
|
|
* index descriptor information
|
|
*/
|
|
/* number of columns in index */
|
|
int ncolumns;
|
|
/* number of key columns in index */
|
|
int nkeycolumns;
|
|
|
|
/*
|
|
* table column numbers of index's columns (both key and included
|
|
* columns), or 0 for expression columns
|
|
*/
|
|
int *indexkeys pg_node_attr(array_size(ncolumns));
|
|
/* OIDs of collations of index columns */
|
|
Oid *indexcollations pg_node_attr(array_size(nkeycolumns));
|
|
/* OIDs of operator families for columns */
|
|
Oid *opfamily pg_node_attr(array_size(nkeycolumns));
|
|
/* OIDs of opclass declared input data types */
|
|
Oid *opcintype pg_node_attr(array_size(nkeycolumns));
|
|
/* OIDs of btree opfamilies, if orderable */
|
|
Oid *sortopfamily pg_node_attr(array_size(nkeycolumns));
|
|
/* is sort order descending? */
|
|
bool *reverse_sort pg_node_attr(array_size(nkeycolumns));
|
|
/* do NULLs come first in the sort order? */
|
|
bool *nulls_first pg_node_attr(array_size(nkeycolumns));
|
|
/* opclass-specific options for columns */
|
|
bytea **opclassoptions pg_node_attr(read_write_ignore);
|
|
/* which index cols can be returned in an index-only scan? */
|
|
bool *canreturn pg_node_attr(array_size(ncolumns));
|
|
/* OID of the access method (in pg_am) */
|
|
Oid relam;
|
|
|
|
/*
|
|
* expressions for non-simple index columns; redundant to print since we
|
|
* print indextlist
|
|
*/
|
|
List *indexprs pg_node_attr(read_write_ignore);
|
|
/* predicate if a partial index, else NIL */
|
|
List *indpred;
|
|
|
|
/* targetlist representing index columns */
|
|
List *indextlist;
|
|
|
|
/*
|
|
* parent relation's baserestrictinfo list, less any conditions implied by
|
|
* the index's predicate (unless it's a target rel, see comments in
|
|
* check_index_predicates())
|
|
*/
|
|
List *indrestrictinfo;
|
|
|
|
/* true if index predicate matches query */
|
|
bool predOK;
|
|
/* true if a unique index */
|
|
bool unique;
|
|
/* is uniqueness enforced immediately? */
|
|
bool immediate;
|
|
/* true if index doesn't really exist */
|
|
bool hypothetical;
|
|
|
|
/*
|
|
* Remaining fields are copied from the index AM's API struct
|
|
* (IndexAmRoutine).
|
|
*/
|
|
bool amcanorderbyop;
|
|
bool amoptionalkey;
|
|
bool amsearcharray;
|
|
bool amsearchnulls;
|
|
/* does AM have amgettuple interface? */
|
|
bool amhasgettuple;
|
|
/* does AM have amgetbitmap interface? */
|
|
bool amhasgetbitmap;
|
|
bool amcanparallel;
|
|
/* does AM have ammarkpos interface? */
|
|
bool amcanmarkpos;
|
|
/* AM's cost estimator */
|
|
/* Rather than include amapi.h here, we declare amcostestimate like this */
|
|
void (*amcostestimate) () pg_node_attr(read_write_ignore);
|
|
};
|
|
|
|
/*
|
|
* ForeignKeyOptInfo
|
|
* Per-foreign-key information for planning/optimization
|
|
*
|
|
* The per-FK-column arrays can be fixed-size because we allow at most
|
|
* INDEX_MAX_KEYS columns in a foreign key constraint. Each array has
|
|
* nkeys valid entries.
|
|
*/
|
|
typedef struct ForeignKeyOptInfo
|
|
{
|
|
pg_node_attr(custom_read_write, no_copy_equal, no_read)
|
|
|
|
NodeTag type;
|
|
|
|
/*
|
|
* Basic data about the foreign key (fetched from catalogs):
|
|
*/
|
|
|
|
/* RT index of the referencing table */
|
|
Index con_relid;
|
|
/* RT index of the referenced table */
|
|
Index ref_relid;
|
|
/* number of columns in the foreign key */
|
|
int nkeys;
|
|
/* cols in referencing table */
|
|
AttrNumber conkey[INDEX_MAX_KEYS] pg_node_attr(array_size(nkeys));
|
|
/* cols in referenced table */
|
|
AttrNumber confkey[INDEX_MAX_KEYS] pg_node_attr(array_size(nkeys));
|
|
/* PK = FK operator OIDs */
|
|
Oid conpfeqop[INDEX_MAX_KEYS] pg_node_attr(array_size(nkeys));
|
|
|
|
/*
|
|
* Derived info about whether FK's equality conditions match the query:
|
|
*/
|
|
|
|
/* # of FK cols matched by ECs */
|
|
int nmatched_ec;
|
|
/* # of these ECs that are ec_has_const */
|
|
int nconst_ec;
|
|
/* # of FK cols matched by non-EC rinfos */
|
|
int nmatched_rcols;
|
|
/* total # of non-EC rinfos matched to FK */
|
|
int nmatched_ri;
|
|
/* Pointer to eclass matching each column's condition, if there is one */
|
|
struct EquivalenceClass *eclass[INDEX_MAX_KEYS];
|
|
/* Pointer to eclass member for the referencing Var, if there is one */
|
|
struct EquivalenceMember *fk_eclass_member[INDEX_MAX_KEYS];
|
|
/* List of non-EC RestrictInfos matching each column's condition */
|
|
List *rinfos[INDEX_MAX_KEYS];
|
|
} ForeignKeyOptInfo;
|
|
|
|
/*
|
|
* StatisticExtInfo
|
|
* Information about extended statistics for planning/optimization
|
|
*
|
|
* Each pg_statistic_ext row is represented by one or more nodes of this
|
|
* type, or even zero if ANALYZE has not computed them.
|
|
*/
|
|
typedef struct StatisticExtInfo
|
|
{
|
|
pg_node_attr(no_copy_equal, no_read)
|
|
|
|
NodeTag type;
|
|
|
|
/* OID of the statistics row */
|
|
Oid statOid;
|
|
|
|
/* includes child relations */
|
|
bool inherit;
|
|
|
|
/* back-link to statistic's table; don't print, else infinite recursion */
|
|
RelOptInfo *rel pg_node_attr(read_write_ignore);
|
|
|
|
/* statistics kind of this entry */
|
|
char kind;
|
|
|
|
/* attnums of the columns covered */
|
|
Bitmapset *keys;
|
|
|
|
/* expressions */
|
|
List *exprs;
|
|
} StatisticExtInfo;
|
|
|
|
/*
|
|
* 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.
|
|
*
|
|
* NB: EquivalenceClasses are never copied after creation. Therefore,
|
|
* copyObject() copies pointers to them as pointers, and equal() compares
|
|
* pointers to EquivalenceClasses via pointer equality. This is implemented
|
|
* by putting copy_as_scalar and equal_as_scalar attributes on fields that
|
|
* are pointers to EquivalenceClasses. The same goes for EquivalenceMembers.
|
|
*/
|
|
typedef struct EquivalenceClass
|
|
{
|
|
pg_node_attr(custom_read_write, no_copy_equal, no_read)
|
|
|
|
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
|
|
{
|
|
pg_node_attr(no_copy_equal, no_read)
|
|
|
|
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
|
|
{
|
|
pg_node_attr(no_read)
|
|
|
|
NodeTag type;
|
|
|
|
/* the value that is ordered */
|
|
EquivalenceClass *pk_eclass pg_node_attr(copy_as_scalar, equal_as_scalar);
|
|
Oid pk_opfamily; /* btree opfamily defining the ordering */
|
|
int pk_strategy; /* sort direction (ASC or DESC) */
|
|
bool pk_nulls_first; /* do NULLs come before normal values? */
|
|
} PathKey;
|
|
|
|
/*
|
|
* VolatileFunctionStatus -- allows nodes to cache their
|
|
* contain_volatile_functions properties. VOLATILITY_UNKNOWN means not yet
|
|
* determined.
|
|
*/
|
|
typedef enum VolatileFunctionStatus
|
|
{
|
|
VOLATILITY_UNKNOWN = 0,
|
|
VOLATILITY_VOLATILE,
|
|
VOLATILITY_NOVOLATILE
|
|
} VolatileFunctionStatus;
|
|
|
|
/*
|
|
* PathTarget
|
|
*
|
|
* This struct contains what we need to know during planning about the
|
|
* targetlist (output columns) that a Path will compute. Each RelOptInfo
|
|
* includes a default PathTarget, which its individual Paths may simply
|
|
* reference. However, in some cases a Path may compute outputs different
|
|
* from other Paths, and in that case we make a custom PathTarget for it.
|
|
* For example, an indexscan might return index expressions that would
|
|
* otherwise need to be explicitly calculated. (Note also that "upper"
|
|
* relations generally don't have useful default PathTargets.)
|
|
*
|
|
* exprs contains bare expressions; they do not have TargetEntry nodes on top,
|
|
* though those will appear in finished Plans.
|
|
*
|
|
* sortgrouprefs[] is an array of the same length as exprs, containing the
|
|
* corresponding sort/group refnos, or zeroes for expressions not referenced
|
|
* by sort/group clauses. If sortgrouprefs is NULL (which it generally is in
|
|
* RelOptInfo.reltarget targets; only upper-level Paths contain this info),
|
|
* we have not identified sort/group columns in this tlist. This allows us to
|
|
* deal with sort/group refnos when needed with less expense than including
|
|
* TargetEntry nodes in the exprs list.
|
|
*/
|
|
typedef struct PathTarget
|
|
{
|
|
pg_node_attr(no_copy_equal, no_read)
|
|
|
|
NodeTag type;
|
|
|
|
/* list of expressions to be computed */
|
|
List *exprs;
|
|
|
|
/* corresponding sort/group refnos, or 0 */
|
|
Index *sortgrouprefs pg_node_attr(array_size(exprs));
|
|
|
|
/* cost of evaluating the expressions */
|
|
QualCost cost;
|
|
|
|
/* estimated avg width of result tuples */
|
|
int width;
|
|
|
|
/* indicates if exprs contain any volatile functions */
|
|
VolatileFunctionStatus has_volatile_expr;
|
|
} PathTarget;
|
|
|
|
/* Convenience macro to get a sort/group refno from a PathTarget */
|
|
#define get_pathtarget_sortgroupref(target, colno) \
|
|
((target)->sortgrouprefs ? (target)->sortgrouprefs[colno] : (Index) 0)
|
|
|
|
|
|
/*
|
|
* ParamPathInfo
|
|
*
|
|
* All parameterized paths for a given relation with given required outer rels
|
|
* link to a single ParamPathInfo, which stores common information such as
|
|
* the estimated rowcount for this parameterization. We do this partly to
|
|
* avoid recalculations, but mostly to ensure that the estimated rowcount
|
|
* is in fact the same for every such path.
|
|
*
|
|
* Note: ppi_clauses is only used in ParamPathInfos for base relation paths;
|
|
* in join cases it's NIL because the set of relevant clauses varies depending
|
|
* on how the join is formed. The relevant clauses will appear in each
|
|
* parameterized join path's joinrestrictinfo list, instead.
|
|
*/
|
|
typedef struct ParamPathInfo
|
|
{
|
|
pg_node_attr(no_copy_equal, no_read)
|
|
|
|
NodeTag type;
|
|
|
|
Relids ppi_req_outer; /* rels supplying parameters used by path */
|
|
Cardinality ppi_rows; /* estimated number of result tuples */
|
|
List *ppi_clauses; /* join clauses available from outer rels */
|
|
} ParamPathInfo;
|
|
|
|
|
|
/*
|
|
* Type "Path" is used as-is for sequential-scan paths, as well as some other
|
|
* simple plan types that we don't need any extra information in the path for.
|
|
* For other path types it is the first component of a larger struct.
|
|
*
|
|
* "pathtype" is the NodeTag of the Plan node we could build from this Path.
|
|
* It is partially redundant with the Path's NodeTag, but allows us to use
|
|
* the same Path type for multiple Plan types when there is no need to
|
|
* distinguish the Plan type during path processing.
|
|
*
|
|
* "parent" identifies the relation this Path scans, and "pathtarget"
|
|
* describes the precise set of output columns the Path would compute.
|
|
* In simple cases all Paths for a given rel share the same targetlist,
|
|
* which we represent by having path->pathtarget equal to parent->reltarget.
|
|
*
|
|
* "param_info", if not NULL, links to a ParamPathInfo that identifies outer
|
|
* relation(s) that provide parameter values to each scan of this path.
|
|
* That means this path can only be joined to those rels by means of nestloop
|
|
* joins with this path on the inside. Also note that a parameterized path
|
|
* is responsible for testing all "movable" joinclauses involving this rel
|
|
* and the specified outer rel(s).
|
|
*
|
|
* "rows" is the same as parent->rows in simple paths, but in parameterized
|
|
* paths and UniquePaths it can be less than parent->rows, reflecting the
|
|
* fact that we've filtered by extra join conditions or removed duplicates.
|
|
*
|
|
* "pathkeys" is a List of PathKey nodes (see above), describing the sort
|
|
* ordering of the path's output rows.
|
|
*
|
|
* We do not support copying Path trees, mainly because the circular linkages
|
|
* between RelOptInfo and Path nodes can't be handled easily in a simple
|
|
* depth-first traversal. We also don't have read support at the moment.
|
|
*/
|
|
typedef struct Path
|
|
{
|
|
pg_node_attr(no_copy_equal, no_read)
|
|
|
|
NodeTag type;
|
|
|
|
/* tag identifying scan/join method */
|
|
NodeTag pathtype;
|
|
|
|
/*
|
|
* the relation this path can build
|
|
*
|
|
* We do NOT print the parent, else we'd be in infinite recursion. We can
|
|
* print the parent's relids for identification purposes, though.
|
|
*/
|
|
RelOptInfo *parent pg_node_attr(write_only_relids);
|
|
|
|
/*
|
|
* list of Vars/Exprs, cost, width
|
|
*
|
|
* We print the pathtarget only if it's not the default one for the rel.
|
|
*/
|
|
PathTarget *pathtarget pg_node_attr(write_only_nondefault_pathtarget);
|
|
|
|
/*
|
|
* parameterization info, or NULL if none
|
|
*
|
|
* We do not print the whole of param_info, since it's printed via
|
|
* RelOptInfo; it's sufficient and less cluttering to print just the
|
|
* required outer relids.
|
|
*/
|
|
ParamPathInfo *param_info pg_node_attr(write_only_req_outer);
|
|
|
|
/* engage parallel-aware logic? */
|
|
bool parallel_aware;
|
|
/* OK to use as part of parallel plan? */
|
|
bool parallel_safe;
|
|
/* desired # of workers; 0 = not parallel */
|
|
int parallel_workers;
|
|
|
|
/* estimated size/costs for path (see costsize.c for more info) */
|
|
Cardinality rows; /* estimated number of result tuples */
|
|
Cost startup_cost; /* cost expended before fetching any tuples */
|
|
Cost total_cost; /* total cost (assuming all tuples fetched) */
|
|
|
|
/* sort ordering of path's output; a List of PathKey nodes; see above */
|
|
List *pathkeys;
|
|
} Path;
|
|
|
|
/* Macro for extracting a path's parameterization relids; beware double eval */
|
|
#define PATH_REQ_OUTER(path) \
|
|
((path)->param_info ? (path)->param_info->ppi_req_outer : (Relids) NULL)
|
|
|
|
/*----------
|
|
* IndexPath represents an index scan over a single index.
|
|
*
|
|
* This struct is used for both regular indexscans and index-only scans;
|
|
* path.pathtype is T_IndexScan or T_IndexOnlyScan to show which is meant.
|
|
*
|
|
* 'indexinfo' is the index to be scanned.
|
|
*
|
|
* 'indexclauses' is a list of IndexClause nodes, each representing one
|
|
* index-checkable restriction, with implicit AND semantics across the list.
|
|
* An empty list implies a full index scan.
|
|
*
|
|
* 'indexorderbys', if not NIL, is a list of ORDER BY expressions that have
|
|
* been found to be usable as ordering operators for an amcanorderbyop index.
|
|
* The list must match the path's pathkeys, ie, one expression per pathkey
|
|
* in the same order. These are not RestrictInfos, just bare expressions,
|
|
* since they generally won't yield booleans. It's guaranteed that each
|
|
* expression has the index key on the left side of the operator.
|
|
*
|
|
* 'indexorderbycols' is an integer list of index column numbers (zero-based)
|
|
* of the same length as 'indexorderbys', showing which index column each
|
|
* ORDER BY expression is meant to be used with. (There is no restriction
|
|
* on which index column each ORDER BY can be used with.)
|
|
*
|
|
* 'indexscandir' is one of:
|
|
* ForwardScanDirection: forward scan of an 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
|
|
{
|
|
pg_node_attr(no_copy_equal, no_read)
|
|
|
|
NodeTag type;
|
|
struct RestrictInfo *rinfo; /* original restriction or join clause */
|
|
List *indexquals; /* indexqual(s) derived from it */
|
|
bool lossy; /* are indexquals a lossy version of clause? */
|
|
AttrNumber indexcol; /* index column the clause uses (zero-based) */
|
|
List *indexcols; /* multiple index columns, if RowCompare */
|
|
} IndexClause;
|
|
|
|
/*
|
|
* BitmapHeapPath represents one or more indexscans that generate TID bitmaps
|
|
* instead of directly accessing the heap, followed by AND/OR combinations
|
|
* to produce a single bitmap, followed by a heap scan that uses the bitmap.
|
|
* Note that the output is always considered unordered, since it will come
|
|
* out in physical heap order no matter what the underlying indexes did.
|
|
*
|
|
* The individual indexscans are represented by IndexPath nodes, and any
|
|
* logic on top of them is represented by a tree of BitmapAndPath and
|
|
* BitmapOrPath nodes. Notice that we can use the same IndexPath node both
|
|
* to represent a regular (or index-only) index scan plan, and as the child
|
|
* of a BitmapHeapPath that represents scanning the same index using a
|
|
* BitmapIndexScan. The startup_cost and total_cost figures of an IndexPath
|
|
* always represent the costs to use it as a regular (or index-only)
|
|
* IndexScan. The costs of a BitmapIndexScan can be computed using the
|
|
* IndexPath's indextotalcost and indexselectivity.
|
|
*/
|
|
typedef struct BitmapHeapPath
|
|
{
|
|
Path path;
|
|
Path *bitmapqual; /* IndexPath, BitmapAndPath, BitmapOrPath */
|
|
} BitmapHeapPath;
|
|
|
|
/*
|
|
* BitmapAndPath represents a BitmapAnd plan node; it can only appear as
|
|
* part of the substructure of a BitmapHeapPath. The Path structure is
|
|
* a bit more heavyweight than we really need for this, but for simplicity
|
|
* we make it a derivative of Path anyway.
|
|
*/
|
|
typedef struct BitmapAndPath
|
|
{
|
|
Path path;
|
|
List *bitmapquals; /* IndexPaths and BitmapOrPaths */
|
|
Selectivity bitmapselectivity;
|
|
} BitmapAndPath;
|
|
|
|
/*
|
|
* BitmapOrPath represents a BitmapOr plan node; it can only appear as
|
|
* part of the substructure of a BitmapHeapPath. The Path structure is
|
|
* a bit more heavyweight than we really need for this, but for simplicity
|
|
* we make it a derivative of Path anyway.
|
|
*/
|
|
typedef struct BitmapOrPath
|
|
{
|
|
Path path;
|
|
List *bitmapquals; /* IndexPaths and BitmapAndPaths */
|
|
Selectivity bitmapselectivity;
|
|
} BitmapOrPath;
|
|
|
|
/*
|
|
* TidPath represents a scan by TID
|
|
*
|
|
* tidquals is an implicitly OR'ed list of qual expressions of the form
|
|
* "CTID = pseudoconstant", or "CTID = ANY(pseudoconstant_array)",
|
|
* or a CurrentOfExpr for the relation.
|
|
*/
|
|
typedef struct TidPath
|
|
{
|
|
Path path;
|
|
List *tidquals; /* qual(s) involving CTID = something */
|
|
} TidPath;
|
|
|
|
/*
|
|
* TidRangePath represents a scan by a contiguous range of TIDs
|
|
*
|
|
* tidrangequals is an implicitly AND'ed list of qual expressions of the form
|
|
* "CTID relop pseudoconstant", where relop is one of >,>=,<,<=.
|
|
*/
|
|
typedef struct TidRangePath
|
|
{
|
|
Path path;
|
|
List *tidrangequals;
|
|
} TidRangePath;
|
|
|
|
/*
|
|
* SubqueryScanPath represents a scan of an unflattened subquery-in-FROM
|
|
*
|
|
* Note that the subpath comes from a different planning domain; for example
|
|
* RTE indexes within it mean something different from those known to the
|
|
* SubqueryScanPath. path.parent->subroot is the planning context needed to
|
|
* interpret the subpath.
|
|
*/
|
|
typedef struct SubqueryScanPath
|
|
{
|
|
Path path;
|
|
Path *subpath; /* path representing subquery execution */
|
|
} SubqueryScanPath;
|
|
|
|
/*
|
|
* ForeignPath represents a potential scan of a foreign table, foreign join
|
|
* or foreign upper-relation.
|
|
*
|
|
* fdw_private stores FDW private data about the scan. While fdw_private is
|
|
* not actually touched by the core code during normal operations, it's
|
|
* generally a good idea to use a representation that can be dumped by
|
|
* nodeToString(), so that you can examine the structure during debugging
|
|
* with tools like pprint().
|
|
*/
|
|
typedef struct ForeignPath
|
|
{
|
|
Path path;
|
|
Path *fdw_outerpath;
|
|
List *fdw_private;
|
|
} ForeignPath;
|
|
|
|
/*
|
|
* CustomPath represents a table scan done by some out-of-core extension.
|
|
*
|
|
* We provide a set of hooks here - which the provider must take care to set
|
|
* up correctly - to allow extensions to supply their own methods of scanning
|
|
* a relation. For example, a provider might provide GPU acceleration, a
|
|
* cache-based scan, or some other kind of logic we haven't dreamed up yet.
|
|
*
|
|
* CustomPaths can be injected into the planning process for a relation by
|
|
* set_rel_pathlist_hook functions.
|
|
*
|
|
* Core code must avoid assuming that the CustomPath is only as large as
|
|
* the structure declared here; providers are allowed to make it the first
|
|
* element in a larger structure. (Since the planner never copies Paths,
|
|
* this doesn't add any complication.) However, for consistency with the
|
|
* FDW case, we provide a "custom_private" field in CustomPath; providers
|
|
* may prefer to use that rather than define another struct type.
|
|
*/
|
|
|
|
struct CustomPathMethods;
|
|
|
|
typedef struct CustomPath
|
|
{
|
|
Path path;
|
|
uint32 flags; /* mask of CUSTOMPATH_* flags, see
|
|
* nodes/extensible.h */
|
|
List *custom_paths; /* list of child Path nodes, if any */
|
|
List *custom_private;
|
|
const struct CustomPathMethods *methods;
|
|
} CustomPath;
|
|
|
|
/*
|
|
* AppendPath represents an Append plan, ie, successive execution of
|
|
* several member plans.
|
|
*
|
|
* For partial Append, 'subpaths' contains non-partial subpaths followed by
|
|
* partial subpaths.
|
|
*
|
|
* Note: it is possible for "subpaths" to contain only one, or even no,
|
|
* elements. These cases are optimized during create_append_plan.
|
|
* In particular, an AppendPath with no subpaths is a "dummy" path that
|
|
* is created to represent the case that a relation is provably empty.
|
|
* (This is a convenient representation because it means that when we build
|
|
* an appendrel and find that all its children have been excluded, no extra
|
|
* action is needed to recognize the relation as dummy.)
|
|
*/
|
|
typedef struct AppendPath
|
|
{
|
|
Path path;
|
|
List *subpaths; /* list of component Paths */
|
|
/* Index of first partial path in subpaths; list_length(subpaths) if none */
|
|
int first_partial_path;
|
|
Cardinality limit_tuples; /* hard limit on output tuples, or -1 */
|
|
} AppendPath;
|
|
|
|
#define IS_DUMMY_APPEND(p) \
|
|
(IsA((p), AppendPath) && ((AppendPath *) (p))->subpaths == NIL)
|
|
|
|
/*
|
|
* A relation that's been proven empty will have one path that is dummy
|
|
* (but might have projection paths on top). For historical reasons,
|
|
* this is provided as a macro that wraps is_dummy_rel().
|
|
*/
|
|
#define IS_DUMMY_REL(r) is_dummy_rel(r)
|
|
extern bool is_dummy_rel(RelOptInfo *rel);
|
|
|
|
/*
|
|
* MergeAppendPath represents a MergeAppend plan, ie, the merging of sorted
|
|
* results from several member plans to produce similarly-sorted output.
|
|
*/
|
|
typedef struct MergeAppendPath
|
|
{
|
|
Path path;
|
|
List *subpaths; /* list of component Paths */
|
|
Cardinality limit_tuples; /* hard limit on output tuples, or -1 */
|
|
} MergeAppendPath;
|
|
|
|
/*
|
|
* GroupResultPath represents use of a Result plan node to compute the
|
|
* output of a degenerate GROUP BY case, wherein we know we should produce
|
|
* exactly one row, which might then be filtered by a HAVING qual.
|
|
*
|
|
* Note that quals is a list of bare clauses, not RestrictInfos.
|
|
*/
|
|
typedef struct GroupResultPath
|
|
{
|
|
Path path;
|
|
List *quals;
|
|
} GroupResultPath;
|
|
|
|
/*
|
|
* MaterialPath represents use of a Material plan node, i.e., caching of
|
|
* the output of its subpath. This is used when the subpath is expensive
|
|
* and needs to be scanned repeatedly, or when we need mark/restore ability
|
|
* and the subpath doesn't have it.
|
|
*/
|
|
typedef struct MaterialPath
|
|
{
|
|
Path path;
|
|
Path *subpath;
|
|
} MaterialPath;
|
|
|
|
/*
|
|
* MemoizePath represents a Memoize plan node, i.e., a cache that caches
|
|
* tuples from parameterized paths to save the underlying node from having to
|
|
* be rescanned for parameter values which are already cached.
|
|
*/
|
|
typedef struct MemoizePath
|
|
{
|
|
Path path;
|
|
Path *subpath; /* outerpath to cache tuples from */
|
|
List *hash_operators; /* OIDs of hash equality ops for cache keys */
|
|
List *param_exprs; /* expressions that are cache keys */
|
|
bool singlerow; /* true if the cache entry is to be marked as
|
|
* complete after caching the first record. */
|
|
bool binary_mode; /* true when cache key should be compared bit
|
|
* by bit, false when using hash equality ops */
|
|
Cardinality calls; /* expected number of rescans */
|
|
uint32 est_entries; /* The maximum number of entries that the
|
|
* planner expects will fit in the cache, or 0
|
|
* if unknown */
|
|
} MemoizePath;
|
|
|
|
/*
|
|
* UniquePath represents elimination of distinct rows from the output of
|
|
* its subpath.
|
|
*
|
|
* This can represent significantly different plans: either hash-based or
|
|
* sort-based implementation, or a no-op if the input path can be proven
|
|
* distinct already. The decision is sufficiently localized that it's not
|
|
* worth having separate Path node types. (Note: in the no-op case, we could
|
|
* eliminate the UniquePath node entirely and just return the subpath; but
|
|
* it's convenient to have a UniquePath in the path tree to signal upper-level
|
|
* routines that the input is known distinct.)
|
|
*/
|
|
typedef enum UniquePathMethod
|
|
{
|
|
UNIQUE_PATH_NOOP, /* input is known unique already */
|
|
UNIQUE_PATH_HASH, /* use hashing */
|
|
UNIQUE_PATH_SORT /* use sorting */
|
|
} UniquePathMethod;
|
|
|
|
typedef struct UniquePath
|
|
{
|
|
Path path;
|
|
Path *subpath;
|
|
UniquePathMethod umethod;
|
|
List *in_operators; /* equality operators of the IN clause */
|
|
List *uniq_exprs; /* expressions to be made unique */
|
|
} UniquePath;
|
|
|
|
/*
|
|
* GatherPath runs several copies of a plan in parallel and collects the
|
|
* results. The parallel leader may also execute the plan, unless the
|
|
* single_copy flag is set.
|
|
*/
|
|
typedef struct GatherPath
|
|
{
|
|
Path path;
|
|
Path *subpath; /* path for each worker */
|
|
bool single_copy; /* don't execute path more than once */
|
|
int num_workers; /* number of workers sought to help */
|
|
} GatherPath;
|
|
|
|
/*
|
|
* GatherMergePath runs several copies of a plan in parallel and collects
|
|
* the results, preserving their common sort order.
|
|
*/
|
|
typedef struct GatherMergePath
|
|
{
|
|
Path path;
|
|
Path *subpath; /* path for each worker */
|
|
int num_workers; /* number of workers sought to help */
|
|
} GatherMergePath;
|
|
|
|
|
|
/*
|
|
* All join-type paths share these fields.
|
|
*/
|
|
|
|
typedef struct JoinPath
|
|
{
|
|
pg_node_attr(abstract)
|
|
|
|
Path path;
|
|
|
|
JoinType jointype;
|
|
|
|
bool inner_unique; /* each outer tuple provably matches no more
|
|
* than one inner tuple */
|
|
|
|
Path *outerjoinpath; /* path for the outer side of the join */
|
|
Path *innerjoinpath; /* path for the inner side of the join */
|
|
|
|
List *joinrestrictinfo; /* RestrictInfos to apply to join */
|
|
|
|
/*
|
|
* See the notes for RelOptInfo and ParamPathInfo to understand why
|
|
* joinrestrictinfo is needed in JoinPath, and can't be merged into the
|
|
* parent RelOptInfo.
|
|
*/
|
|
} JoinPath;
|
|
|
|
/*
|
|
* A nested-loop path needs no special fields.
|
|
*/
|
|
|
|
typedef struct NestPath
|
|
{
|
|
JoinPath jpath;
|
|
} NestPath;
|
|
|
|
/*
|
|
* A mergejoin path has these fields.
|
|
*
|
|
* Unlike other path types, a MergePath node doesn't represent just a single
|
|
* run-time plan node: it can represent up to four. Aside from the MergeJoin
|
|
* node itself, there can be a Sort node for the outer input, a Sort node
|
|
* for the inner input, and/or a Material node for the inner input. We could
|
|
* represent these nodes by separate path nodes, but considering how many
|
|
* different merge paths are investigated during a complex join problem,
|
|
* it seems better to avoid unnecessary palloc overhead.
|
|
*
|
|
* path_mergeclauses lists the clauses (in the form of RestrictInfos)
|
|
* that will be used in the merge.
|
|
*
|
|
* Note that the mergeclauses are a subset of the parent relation's
|
|
* restriction-clause list. Any join clauses that are not mergejoinable
|
|
* appear only in the parent's restrict list, and must be checked by a
|
|
* qpqual at execution time.
|
|
*
|
|
* outersortkeys (resp. innersortkeys) is NIL if the outer path
|
|
* (resp. inner path) is already ordered appropriately for the
|
|
* mergejoin. If it is not NIL then it is a PathKeys list describing
|
|
* the ordering that must be created by an explicit Sort node.
|
|
*
|
|
* skip_mark_restore is true if the executor need not do mark/restore calls.
|
|
* Mark/restore overhead is usually required, but can be skipped if we know
|
|
* that the executor need find only one match per outer tuple, and that the
|
|
* mergeclauses are sufficient to identify a match. In such cases the
|
|
* executor can immediately advance the outer relation after processing a
|
|
* match, and therefore it need never back up the inner relation.
|
|
*
|
|
* materialize_inner is true if a Material node should be placed atop the
|
|
* inner input. This may appear with or without an inner Sort step.
|
|
*/
|
|
|
|
typedef struct MergePath
|
|
{
|
|
JoinPath jpath;
|
|
List *path_mergeclauses; /* join clauses to be used for merge */
|
|
List *outersortkeys; /* keys for explicit sort, if any */
|
|
List *innersortkeys; /* keys for explicit sort, if any */
|
|
bool skip_mark_restore; /* can executor skip mark/restore? */
|
|
bool materialize_inner; /* add Materialize to inner? */
|
|
} MergePath;
|
|
|
|
/*
|
|
* A hashjoin path has these fields.
|
|
*
|
|
* The remarks above for mergeclauses apply for hashclauses as well.
|
|
*
|
|
* Hashjoin does not care what order its inputs appear in, so we have
|
|
* no need for sortkeys.
|
|
*/
|
|
|
|
typedef struct HashPath
|
|
{
|
|
JoinPath jpath;
|
|
List *path_hashclauses; /* join clauses used for hashing */
|
|
int num_batches; /* number of batches expected */
|
|
Cardinality inner_rows_total; /* total inner rows expected */
|
|
} HashPath;
|
|
|
|
/*
|
|
* ProjectionPath represents a projection (that is, targetlist computation)
|
|
*
|
|
* Nominally, this path node represents using a Result plan node to do a
|
|
* projection step. However, if the input plan node supports projection,
|
|
* we can just modify its output targetlist to do the required calculations
|
|
* directly, and not need a Result. In some places in the planner we can just
|
|
* jam the desired PathTarget into the input path node (and adjust its cost
|
|
* accordingly), so we don't need a ProjectionPath. But in other places
|
|
* it's necessary to not modify the input path node, so we need a separate
|
|
* ProjectionPath node, which is marked dummy to indicate that we intend to
|
|
* assign the work to the input plan node. The estimated cost for the
|
|
* ProjectionPath node will account for whether a Result will be used or not.
|
|
*/
|
|
typedef struct ProjectionPath
|
|
{
|
|
Path path;
|
|
Path *subpath; /* path representing input source */
|
|
bool dummypp; /* true if no separate Result is needed */
|
|
} ProjectionPath;
|
|
|
|
/*
|
|
* ProjectSetPath represents evaluation of a targetlist that includes
|
|
* set-returning function(s), which will need to be implemented by a
|
|
* ProjectSet plan node.
|
|
*/
|
|
typedef struct ProjectSetPath
|
|
{
|
|
Path path;
|
|
Path *subpath; /* path representing input source */
|
|
} ProjectSetPath;
|
|
|
|
/*
|
|
* SortPath represents an explicit sort step
|
|
*
|
|
* The sort keys are, by definition, the same as path.pathkeys.
|
|
*
|
|
* Note: the Sort plan node cannot project, so path.pathtarget must be the
|
|
* same as the input's pathtarget.
|
|
*/
|
|
typedef struct SortPath
|
|
{
|
|
Path path;
|
|
Path *subpath; /* path representing input source */
|
|
} SortPath;
|
|
|
|
/*
|
|
* IncrementalSortPath represents an incremental sort step
|
|
*
|
|
* This is like a regular sort, except some leading key columns are assumed
|
|
* to be ordered already.
|
|
*/
|
|
typedef struct IncrementalSortPath
|
|
{
|
|
SortPath spath;
|
|
int nPresortedCols; /* number of presorted columns */
|
|
} IncrementalSortPath;
|
|
|
|
/*
|
|
* GroupPath represents grouping (of presorted input)
|
|
*
|
|
* groupClause represents the columns to be grouped on; the input path
|
|
* must be at least that well sorted.
|
|
*
|
|
* We can also apply a qual to the grouped rows (equivalent of HAVING)
|
|
*/
|
|
typedef struct GroupPath
|
|
{
|
|
Path path;
|
|
Path *subpath; /* path representing input source */
|
|
List *groupClause; /* a list of SortGroupClause's */
|
|
List *qual; /* quals (HAVING quals), if any */
|
|
} GroupPath;
|
|
|
|
/*
|
|
* UpperUniquePath represents adjacent-duplicate removal (in presorted input)
|
|
*
|
|
* The columns to be compared are the first numkeys columns of the path's
|
|
* pathkeys. The input is presumed already sorted that way.
|
|
*/
|
|
typedef struct UpperUniquePath
|
|
{
|
|
Path path;
|
|
Path *subpath; /* path representing input source */
|
|
int numkeys; /* number of pathkey columns to compare */
|
|
} UpperUniquePath;
|
|
|
|
/*
|
|
* AggPath represents generic computation of aggregate functions
|
|
*
|
|
* This may involve plain grouping (but not grouping sets), using either
|
|
* sorted or hashed grouping; for the AGG_SORTED case, the input must be
|
|
* appropriately presorted.
|
|
*/
|
|
typedef struct AggPath
|
|
{
|
|
Path path;
|
|
Path *subpath; /* path representing input source */
|
|
AggStrategy aggstrategy; /* basic strategy, see nodes.h */
|
|
AggSplit aggsplit; /* agg-splitting mode, see nodes.h */
|
|
Cardinality numGroups; /* estimated number of groups in input */
|
|
uint64 transitionSpace; /* for pass-by-ref transition data */
|
|
List *groupClause; /* a list of SortGroupClause's */
|
|
List *qual; /* quals (HAVING quals), if any */
|
|
} AggPath;
|
|
|
|
/*
|
|
* Various annotations used for grouping sets in the planner.
|
|
*/
|
|
|
|
typedef struct GroupingSetData
|
|
{
|
|
pg_node_attr(no_copy_equal, no_read)
|
|
|
|
NodeTag type;
|
|
List *set; /* grouping set as list of sortgrouprefs */
|
|
Cardinality numGroups; /* est. number of result groups */
|
|
} GroupingSetData;
|
|
|
|
typedef struct RollupData
|
|
{
|
|
pg_node_attr(no_copy_equal, no_read)
|
|
|
|
NodeTag type;
|
|
List *groupClause; /* applicable subset of parse->groupClause */
|
|
List *gsets; /* lists of integer indexes into groupClause */
|
|
List *gsets_data; /* list of GroupingSetData */
|
|
Cardinality numGroups; /* est. number of result groups */
|
|
bool hashable; /* can be hashed */
|
|
bool is_hashed; /* to be implemented as a hashagg */
|
|
} RollupData;
|
|
|
|
/*
|
|
* GroupingSetsPath represents a GROUPING SETS aggregation
|
|
*/
|
|
|
|
typedef struct GroupingSetsPath
|
|
{
|
|
Path path;
|
|
Path *subpath; /* path representing input source */
|
|
AggStrategy aggstrategy; /* basic strategy */
|
|
List *rollups; /* list of RollupData */
|
|
List *qual; /* quals (HAVING quals), if any */
|
|
uint64 transitionSpace; /* for pass-by-ref transition data */
|
|
} GroupingSetsPath;
|
|
|
|
/*
|
|
* MinMaxAggPath represents computation of MIN/MAX aggregates from indexes
|
|
*/
|
|
typedef struct MinMaxAggPath
|
|
{
|
|
Path path;
|
|
List *mmaggregates; /* list of MinMaxAggInfo */
|
|
List *quals; /* HAVING quals, if any */
|
|
} MinMaxAggPath;
|
|
|
|
/*
|
|
* WindowAggPath represents generic computation of window functions
|
|
*/
|
|
typedef struct WindowAggPath
|
|
{
|
|
Path path;
|
|
Path *subpath; /* path representing input source */
|
|
WindowClause *winclause; /* WindowClause we'll be using */
|
|
List *qual; /* lower-level WindowAgg runconditions */
|
|
bool topwindow; /* false for all apart from the WindowAgg
|
|
* that's closest to the root of the plan */
|
|
} WindowAggPath;
|
|
|
|
/*
|
|
* SetOpPath represents a set-operation, that is INTERSECT or EXCEPT
|
|
*/
|
|
typedef struct SetOpPath
|
|
{
|
|
Path path;
|
|
Path *subpath; /* path representing input source */
|
|
SetOpCmd cmd; /* what to do, see nodes.h */
|
|
SetOpStrategy strategy; /* how to do it, see nodes.h */
|
|
List *distinctList; /* SortGroupClauses identifying target cols */
|
|
AttrNumber flagColIdx; /* where is the flag column, if any */
|
|
int firstFlag; /* flag value for first input relation */
|
|
Cardinality numGroups; /* estimated number of groups in input */
|
|
} SetOpPath;
|
|
|
|
/*
|
|
* RecursiveUnionPath represents a recursive UNION node
|
|
*/
|
|
typedef struct RecursiveUnionPath
|
|
{
|
|
Path path;
|
|
Path *leftpath; /* paths representing input sources */
|
|
Path *rightpath;
|
|
List *distinctList; /* SortGroupClauses identifying target cols */
|
|
int wtParam; /* ID of Param representing work table */
|
|
Cardinality numGroups; /* estimated number of groups in input */
|
|
} RecursiveUnionPath;
|
|
|
|
/*
|
|
* LockRowsPath represents acquiring row locks for SELECT FOR UPDATE/SHARE
|
|
*/
|
|
typedef struct LockRowsPath
|
|
{
|
|
Path path;
|
|
Path *subpath; /* path representing input source */
|
|
List *rowMarks; /* a list of PlanRowMark's */
|
|
int epqParam; /* ID of Param for EvalPlanQual re-eval */
|
|
} LockRowsPath;
|
|
|
|
/*
|
|
* ModifyTablePath represents performing INSERT/UPDATE/DELETE/MERGE
|
|
*
|
|
* We represent most things that will be in the ModifyTable plan node
|
|
* literally, except we have a child Path not Plan. But analysis of the
|
|
* OnConflictExpr is deferred to createplan.c, as is collection of FDW data.
|
|
*/
|
|
typedef struct ModifyTablePath
|
|
{
|
|
Path path;
|
|
Path *subpath; /* Path producing source data */
|
|
CmdType operation; /* INSERT, UPDATE, DELETE, or MERGE */
|
|
bool canSetTag; /* do we set the command tag/es_processed? */
|
|
Index nominalRelation; /* Parent RT index for use of EXPLAIN */
|
|
Index rootRelation; /* Root RT index, if target is partitioned */
|
|
bool partColsUpdated; /* some part key in hierarchy updated? */
|
|
List *resultRelations; /* integer list of RT indexes */
|
|
List *updateColnosLists; /* per-target-table update_colnos lists */
|
|
List *withCheckOptionLists; /* per-target-table WCO lists */
|
|
List *returningLists; /* per-target-table RETURNING tlists */
|
|
List *rowMarks; /* PlanRowMarks (non-locking only) */
|
|
OnConflictExpr *onconflict; /* ON CONFLICT clause, or NULL */
|
|
int epqParam; /* ID of Param for EvalPlanQual re-eval */
|
|
List *mergeActionLists; /* per-target-table lists of actions for
|
|
* MERGE */
|
|
} ModifyTablePath;
|
|
|
|
/*
|
|
* LimitPath represents applying LIMIT/OFFSET restrictions
|
|
*/
|
|
typedef struct LimitPath
|
|
{
|
|
Path path;
|
|
Path *subpath; /* path representing input source */
|
|
Node *limitOffset; /* OFFSET parameter, or NULL if none */
|
|
Node *limitCount; /* COUNT parameter, or NULL if none */
|
|
LimitOption limitOption; /* FETCH FIRST with ties or exact number */
|
|
} LimitPath;
|
|
|
|
|
|
/*
|
|
* Restriction clause info.
|
|
*
|
|
* We create one of these for each AND sub-clause of a restriction condition
|
|
* (WHERE or JOIN/ON clause). Since the restriction clauses are logically
|
|
* ANDed, we can use any one of them or any subset of them to filter out
|
|
* tuples, without having to evaluate the rest. The RestrictInfo node itself
|
|
* stores data used by the optimizer while choosing the best query plan.
|
|
*
|
|
* If a restriction clause references a single base relation, it will appear
|
|
* in the baserestrictinfo list of the RelOptInfo for that base rel.
|
|
*
|
|
* If a restriction clause references more than one base 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.
|
|
*
|
|
* Most fields are ignored for equality, since they may not be set yet, and
|
|
* should be derivable from the clause anyway.
|
|
*
|
|
* parent_ec, left_ec, right_ec are not printed, lest it lead to infinite
|
|
* recursion in plan tree dump.
|
|
*/
|
|
|
|
typedef struct RestrictInfo
|
|
{
|
|
pg_node_attr(no_read)
|
|
|
|
NodeTag type;
|
|
|
|
/* the represented clause of WHERE or JOIN */
|
|
Expr *clause;
|
|
|
|
/* true if clause was pushed down in level */
|
|
bool is_pushed_down;
|
|
|
|
/* true if delayed by lower outer join */
|
|
bool outerjoin_delayed;
|
|
|
|
/* see comment above */
|
|
bool can_join pg_node_attr(equal_ignore);
|
|
|
|
/* see comment above */
|
|
bool pseudoconstant pg_node_attr(equal_ignore);
|
|
|
|
/* true if known to contain no leaked Vars */
|
|
bool leakproof pg_node_attr(equal_ignore);
|
|
|
|
/* to indicate if clause contains any volatile functions. */
|
|
VolatileFunctionStatus has_volatile pg_node_attr(equal_ignore);
|
|
|
|
/* see comment above */
|
|
Index security_level;
|
|
|
|
/* The set of relids (varnos) actually referenced in the clause: */
|
|
Relids clause_relids pg_node_attr(equal_ignore);
|
|
|
|
/* The set of relids required to evaluate the clause: */
|
|
Relids required_relids;
|
|
|
|
/* 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;
|
|
|
|
/*
|
|
* Relids in the left/right side of the clause. These fields are set for
|
|
* any binary opclause.
|
|
*/
|
|
Relids left_relids pg_node_attr(equal_ignore);
|
|
Relids right_relids pg_node_attr(equal_ignore);
|
|
|
|
/*
|
|
* Modified clause with RestrictInfos. This field is NULL unless clause
|
|
* is an OR clause.
|
|
*/
|
|
Expr *orclause pg_node_attr(equal_ignore);
|
|
|
|
/*
|
|
* Generating EquivalenceClass. This field is NULL unless clause is
|
|
* potentially redundant.
|
|
*/
|
|
EquivalenceClass *parent_ec pg_node_attr(copy_as_scalar, equal_ignore, read_write_ignore);
|
|
|
|
/*
|
|
* cache space for cost and selectivity
|
|
*/
|
|
|
|
/* eval cost of clause; -1 if not yet set */
|
|
QualCost eval_cost pg_node_attr(equal_ignore);
|
|
|
|
/*
|
|
* selectivity for "normal" (JOIN_INNER) semantics; -1 if not yet set; >1
|
|
* means a redundant clause
|
|
*/
|
|
Selectivity norm_selec pg_node_attr(equal_ignore);
|
|
/* selectivity for outer join semantics; -1 if not yet set */
|
|
Selectivity outer_selec pg_node_attr(equal_ignore);
|
|
|
|
/*
|
|
* opfamilies containing clause operator; valid if clause is
|
|
* mergejoinable, else NIL
|
|
*/
|
|
List *mergeopfamilies pg_node_attr(equal_ignore);
|
|
|
|
/*
|
|
* cache space for mergeclause processing; NULL if not yet set
|
|
*/
|
|
|
|
/* EquivalenceClass containing lefthand */
|
|
EquivalenceClass *left_ec pg_node_attr(copy_as_scalar, equal_ignore, read_write_ignore);
|
|
/* EquivalenceClass containing righthand */
|
|
EquivalenceClass *right_ec pg_node_attr(copy_as_scalar, equal_ignore, read_write_ignore);
|
|
/* EquivalenceMember for lefthand */
|
|
EquivalenceMember *left_em pg_node_attr(copy_as_scalar, equal_ignore);
|
|
/* EquivalenceMember for righthand */
|
|
EquivalenceMember *right_em pg_node_attr(copy_as_scalar, equal_ignore);
|
|
|
|
/*
|
|
* List of MergeScanSelCache structs. Those aren't Nodes, so hard to
|
|
* copy; instead replace with NIL. That has the effect that copying will
|
|
* just reset the cache. Likewise, can't compare or print them.
|
|
*/
|
|
List *scansel_cache pg_node_attr(copy_as(NIL), equal_ignore, read_write_ignore);
|
|
|
|
/*
|
|
* transient workspace for use while considering a specific join path; T =
|
|
* outer var on left, F = on right
|
|
*/
|
|
bool outer_is_left pg_node_attr(equal_ignore);
|
|
|
|
/*
|
|
* copy of clause operator; valid if clause is hashjoinable, else
|
|
* InvalidOid
|
|
*/
|
|
Oid hashjoinoperator pg_node_attr(equal_ignore);
|
|
|
|
/*
|
|
* cache space for hashclause processing; -1 if not yet set
|
|
*/
|
|
/* avg bucketsize of left side */
|
|
Selectivity left_bucketsize pg_node_attr(equal_ignore);
|
|
/* avg bucketsize of right side */
|
|
Selectivity right_bucketsize pg_node_attr(equal_ignore);
|
|
/* left side's most common val's freq */
|
|
Selectivity left_mcvfreq pg_node_attr(equal_ignore);
|
|
/* right side's most common val's freq */
|
|
Selectivity right_mcvfreq pg_node_attr(equal_ignore);
|
|
|
|
/* hash equality operators used for memoize nodes, else InvalidOid */
|
|
Oid left_hasheqoperator pg_node_attr(equal_ignore);
|
|
Oid right_hasheqoperator pg_node_attr(equal_ignore);
|
|
} RestrictInfo;
|
|
|
|
/*
|
|
* This macro embodies the correct way to test whether a RestrictInfo is
|
|
* "pushed down" to a given outer join, that is, should be treated as a filter
|
|
* clause rather than a join clause at that outer join. This is certainly so
|
|
* if is_pushed_down is true; but examining that is not sufficient anymore,
|
|
* because outer-join clauses will get pushed down to lower outer joins when
|
|
* we generate a path for the lower outer join that is parameterized by the
|
|
* LHS of the upper one. We can detect such a clause by noting that its
|
|
* required_relids exceed the scope of the join.
|
|
*/
|
|
#define RINFO_IS_PUSHED_DOWN(rinfo, joinrelids) \
|
|
((rinfo)->is_pushed_down || \
|
|
!bms_is_subset((rinfo)->required_relids, joinrelids))
|
|
|
|
/*
|
|
* Since mergejoinscansel() is a relatively expensive function, and would
|
|
* otherwise be invoked many times while planning a large join tree,
|
|
* we go out of our way to cache its results. Each mergejoinable
|
|
* RestrictInfo carries a list of the specific sort orderings that have
|
|
* been considered for use with it, and the resulting selectivities.
|
|
*/
|
|
typedef struct MergeScanSelCache
|
|
{
|
|
/* Ordering details (cache lookup key) */
|
|
Oid opfamily; /* btree opfamily defining the ordering */
|
|
Oid collation; /* collation for the ordering */
|
|
int strategy; /* sort direction (ASC or DESC) */
|
|
bool nulls_first; /* do NULLs come before normal values? */
|
|
/* Results */
|
|
Selectivity leftstartsel; /* first-join fraction for clause left side */
|
|
Selectivity leftendsel; /* last-join fraction for clause left side */
|
|
Selectivity rightstartsel; /* first-join fraction for clause right side */
|
|
Selectivity rightendsel; /* last-join fraction for clause right side */
|
|
} MergeScanSelCache;
|
|
|
|
/*
|
|
* Placeholder node for an expression to be evaluated below the top level
|
|
* of a plan tree. This is used during planning to represent the contained
|
|
* expression. At the end of the planning process it is replaced by either
|
|
* the contained expression or a Var referring to a lower-level evaluation of
|
|
* the contained expression. 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.
|
|
*
|
|
* We intentionally do not compare phexpr. Two PlaceHolderVars with the
|
|
* same ID and levelsup should be considered equal even if the contained
|
|
* expressions have managed to mutate to different states. This will
|
|
* happen during final plan construction when there are nested PHVs, since
|
|
* the inner PHV will get replaced by a Param in some copies of the outer
|
|
* PHV. Another way in which it can happen is that initplan sublinks
|
|
* could get replaced by differently-numbered Params when sublink folding
|
|
* is done. (The end result of such a situation would be some
|
|
* unreferenced initplans, which is annoying but not really a problem.) On
|
|
* the same reasoning, there is no need to examine phrels.
|
|
*/
|
|
|
|
typedef struct PlaceHolderVar
|
|
{
|
|
Expr xpr;
|
|
|
|
/* the represented expression */
|
|
Expr *phexpr pg_node_attr(equal_ignore);
|
|
|
|
/* base relids syntactically within expr src */
|
|
Relids phrels pg_node_attr(equal_ignore);
|
|
|
|
/* ID for PHV (unique within planner run) */
|
|
Index phid;
|
|
|
|
/* > 0 if PHV belongs to outer query */
|
|
Index phlevelsup;
|
|
} PlaceHolderVar;
|
|
|
|
/*
|
|
* "Special join" info.
|
|
*
|
|
* One-sided outer joins constrain the order of joining partially but not
|
|
* completely. We flatten such joins into the planner's top-level list of
|
|
* relations to join, but record information about each outer join in a
|
|
* SpecialJoinInfo struct. These structs are kept in the PlannerInfo node's
|
|
* join_info_list.
|
|
*
|
|
* Similarly, semijoins and antijoins created by flattening IN (subselect)
|
|
* and EXISTS(subselect) clauses create partial constraints on join order.
|
|
* These are likewise recorded in SpecialJoinInfo structs.
|
|
*
|
|
* We make SpecialJoinInfos for FULL JOINs even though there is no flexibility
|
|
* of planning for them, because this simplifies make_join_rel()'s API.
|
|
*
|
|
* min_lefthand and min_righthand are the sets of base 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
|
|
{
|
|
pg_node_attr(no_read)
|
|
|
|
NodeTag type;
|
|
Relids min_lefthand; /* base relids in minimum LHS for join */
|
|
Relids min_righthand; /* base relids in minimum RHS for join */
|
|
Relids syn_lefthand; /* base relids syntactically within LHS */
|
|
Relids syn_righthand; /* base relids syntactically within RHS */
|
|
JoinType jointype; /* always INNER, LEFT, FULL, SEMI, or ANTI */
|
|
bool lhs_strict; /* joinclause is strict for some LHS rel */
|
|
bool delay_upper_joins; /* can't commute with upper RHS */
|
|
/* Remaining fields are set only for JOIN_SEMI jointype: */
|
|
bool semi_can_btree; /* true if semi_operators are all btree */
|
|
bool semi_can_hash; /* true if semi_operators are all hash */
|
|
List *semi_operators; /* OIDs of equality join operators */
|
|
List *semi_rhs_exprs; /* righthand-side expressions of these ops */
|
|
};
|
|
|
|
/*
|
|
* Append-relation info.
|
|
*
|
|
* When we expand an inheritable table or a UNION-ALL subselect into an
|
|
* "append relation" (essentially, a list of child RTEs), we build an
|
|
* AppendRelInfo for each child RTE. The list of AppendRelInfos indicates
|
|
* which child RTEs must be included when expanding the parent, and each node
|
|
* carries information needed to translate between columns of the parent and
|
|
* columns of the child.
|
|
*
|
|
* These structs are kept in the PlannerInfo node's append_rel_list, with
|
|
* append_rel_array[] providing a convenient lookup method for the struct
|
|
* associated with a particular child relid (there can be only one, though
|
|
* parent rels may have many entries in append_rel_list).
|
|
*
|
|
* Note: after completion of the planner prep phase, any given RTE is an
|
|
* append parent having entries in append_rel_list if and only if its
|
|
* "inh" flag is set. We clear "inh" for plain tables that turn out not
|
|
* to have inheritance children, and (in an abuse of the original meaning
|
|
* of the flag) we set "inh" for subquery RTEs that turn out to be
|
|
* flattenable UNION ALL queries. This lets us avoid useless searches
|
|
* of append_rel_list.
|
|
*
|
|
* Note: the data structure assumes that append-rel members are single
|
|
* baserels. This is OK for inheritance, but it prevents us from pulling
|
|
* up a UNION ALL member subquery if it contains a join. While that could
|
|
* be fixed with a more complex data structure, at present there's not much
|
|
* point because no improvement in the plan could result.
|
|
*/
|
|
|
|
typedef struct AppendRelInfo
|
|
{
|
|
NodeTag type;
|
|
|
|
/*
|
|
* These fields uniquely identify this append relationship. There can be
|
|
* (in fact, always should be) multiple AppendRelInfos for the same
|
|
* parent_relid, but never more than one per child_relid, since a given
|
|
* RTE cannot be a child of more than one append parent.
|
|
*/
|
|
Index parent_relid; /* RT index of append parent rel */
|
|
Index child_relid; /* RT index of append child rel */
|
|
|
|
/*
|
|
* For an inheritance appendrel, the parent and child are both regular
|
|
* relations, and we store their rowtype OIDs here for use in translating
|
|
* whole-row Vars. For a UNION-ALL appendrel, the parent and child are
|
|
* both subqueries with no named rowtype, and we store InvalidOid here.
|
|
*/
|
|
Oid parent_reltype; /* OID of parent's composite type */
|
|
Oid child_reltype; /* OID of child's composite type */
|
|
|
|
/*
|
|
* The N'th element of this list is a Var or expression representing the
|
|
* child column corresponding to the N'th column of the parent. This is
|
|
* used to translate Vars referencing the parent rel into references to
|
|
* the child. A list element is NULL if it corresponds to a dropped
|
|
* column of the parent (this is only possible for inheritance cases, not
|
|
* UNION ALL). The list elements are always simple Vars for inheritance
|
|
* cases, but can be arbitrary expressions in UNION ALL cases.
|
|
*
|
|
* Notice we only store entries for user columns (attno > 0). Whole-row
|
|
* Vars are special-cased, and system columns (attno < 0) need no special
|
|
* translation since their attnos are the same for all tables.
|
|
*
|
|
* Caution: the Vars have varlevelsup = 0. Be careful to adjust as needed
|
|
* when copying into a subquery.
|
|
*/
|
|
List *translated_vars; /* Expressions in the child's Vars */
|
|
|
|
/*
|
|
* This array simplifies translations in the reverse direction, from
|
|
* child's column numbers to parent's. The entry at [ccolno - 1] is the
|
|
* 1-based parent column number for child column ccolno, or zero if that
|
|
* child column is dropped or doesn't exist in the parent.
|
|
*/
|
|
int num_child_cols; /* length of array */
|
|
AttrNumber *parent_colnos pg_node_attr(array_size(num_child_cols));
|
|
|
|
/*
|
|
* We store the parent table's OID here for inheritance, or InvalidOid for
|
|
* UNION ALL. This is only needed to help in generating error messages if
|
|
* an attempt is made to reference a dropped parent column.
|
|
*/
|
|
Oid parent_reloid; /* OID of parent relation */
|
|
} AppendRelInfo;
|
|
|
|
/*
|
|
* Information about a row-identity "resjunk" column in UPDATE/DELETE/MERGE.
|
|
*
|
|
* In partitioned UPDATE/DELETE/MERGE it's important for child partitions to
|
|
* share row-identity columns whenever possible, so as not to chew up too many
|
|
* targetlist columns. We use these structs to track which identity columns
|
|
* have been requested. In the finished plan, each of these will give rise
|
|
* to one resjunk entry in the targetlist of the ModifyTable's subplan node.
|
|
*
|
|
* All the Vars stored in RowIdentityVarInfos must have varno ROWID_VAR, for
|
|
* convenience of detecting duplicate requests. We'll replace that, in the
|
|
* final plan, with the varno of the generating rel.
|
|
*
|
|
* Outside this list, a Var with varno ROWID_VAR and varattno k is a reference
|
|
* to the k-th element of the row_identity_vars list (k counting from 1).
|
|
* We add such a reference to root->processed_tlist when creating the entry,
|
|
* and it propagates into the plan tree from there.
|
|
*/
|
|
typedef struct RowIdentityVarInfo
|
|
{
|
|
pg_node_attr(no_copy_equal, no_read)
|
|
|
|
NodeTag type;
|
|
|
|
Var *rowidvar; /* Var to be evaluated (but varno=ROWID_VAR) */
|
|
int32 rowidwidth; /* estimated average width */
|
|
char *rowidname; /* name of the resjunk column */
|
|
Relids rowidrels; /* RTE indexes of target rels using this */
|
|
} RowIdentityVarInfo;
|
|
|
|
/*
|
|
* For each distinct placeholder expression generated during planning, we
|
|
* store a PlaceHolderInfo node in the PlannerInfo node's placeholder_list.
|
|
* This stores info that is needed centrally rather than in each copy of the
|
|
* PlaceHolderVar. The phid fields identify which PlaceHolderInfo goes with
|
|
* each PlaceHolderVar. Note that phid is unique throughout a planner run,
|
|
* not just within a query level --- this is so that we need not reassign ID's
|
|
* when pulling a subquery into its parent.
|
|
*
|
|
* The idea is to evaluate the expression at (only) the ph_eval_at join level,
|
|
* then allow it to bubble up like a Var until the ph_needed join level.
|
|
* ph_needed has the same definition as attr_needed for a regular Var.
|
|
*
|
|
* The PlaceHolderVar's expression might contain LATERAL references to vars
|
|
* coming from outside its syntactic scope. If so, those rels are *not*
|
|
* included in ph_eval_at, but they are recorded in ph_lateral.
|
|
*
|
|
* Notice that when ph_eval_at is a join rather than a single baserel, the
|
|
* PlaceHolderInfo may create constraints on join order: the ph_eval_at join
|
|
* has to be formed below any outer joins that should null the PlaceHolderVar.
|
|
*
|
|
* We create a PlaceHolderInfo only after determining that the PlaceHolderVar
|
|
* is actually referenced in the plan tree, so that unreferenced placeholders
|
|
* don't result in unnecessary constraints on join order.
|
|
*/
|
|
|
|
typedef struct PlaceHolderInfo
|
|
{
|
|
pg_node_attr(no_read)
|
|
|
|
NodeTag type;
|
|
|
|
/* ID for PH (unique within planner run) */
|
|
Index phid;
|
|
|
|
/*
|
|
* copy of PlaceHolderVar tree (should be redundant for comparison, could
|
|
* be ignored)
|
|
*/
|
|
PlaceHolderVar *ph_var;
|
|
|
|
/* lowest level we can evaluate value at */
|
|
Relids ph_eval_at;
|
|
|
|
/* relids of contained lateral refs, if any */
|
|
Relids ph_lateral;
|
|
|
|
/* highest level the value is needed at */
|
|
Relids ph_needed;
|
|
|
|
/* estimated attribute width */
|
|
int32 ph_width;
|
|
} PlaceHolderInfo;
|
|
|
|
/*
|
|
* This struct describes one potentially index-optimizable MIN/MAX aggregate
|
|
* function. MinMaxAggPath contains a list of these, and if we accept that
|
|
* path, the list is stored into root->minmax_aggs for use during setrefs.c.
|
|
*/
|
|
typedef struct MinMaxAggInfo
|
|
{
|
|
pg_node_attr(no_copy_equal, no_read)
|
|
|
|
NodeTag type;
|
|
|
|
/* pg_proc Oid of the aggregate */
|
|
Oid aggfnoid;
|
|
|
|
/* Oid of its sort operator */
|
|
Oid aggsortop;
|
|
|
|
/* expression we are aggregating on */
|
|
Expr *target;
|
|
|
|
/*
|
|
* modified "root" for planning the subquery; not printed, too large, not
|
|
* interesting enough
|
|
*/
|
|
PlannerInfo *subroot pg_node_attr(read_write_ignore);
|
|
|
|
/* access path for subquery */
|
|
Path *path;
|
|
|
|
/* estimated cost to fetch first row */
|
|
Cost pathcost;
|
|
|
|
/* param for subplan's output */
|
|
Param *param;
|
|
} MinMaxAggInfo;
|
|
|
|
/*
|
|
* At runtime, PARAM_EXEC slots are used to pass values around from one plan
|
|
* node to another. They can be used to pass values down into subqueries (for
|
|
* outer references in subqueries), or up out of subqueries (for the results
|
|
* of a subplan), or from a NestLoop plan node into its inner relation (when
|
|
* the inner scan is parameterized with values from the outer relation).
|
|
* The planner is responsible for assigning nonconflicting PARAM_EXEC IDs to
|
|
* the PARAM_EXEC Params it generates.
|
|
*
|
|
* Outer references are managed via root->plan_params, which is a list of
|
|
* PlannerParamItems. While planning a subquery, each parent query level's
|
|
* plan_params contains the values required from it by the current subquery.
|
|
* During create_plan(), we use plan_params to track values that must be
|
|
* passed from outer to inner sides of NestLoop plan nodes.
|
|
*
|
|
* The item a PlannerParamItem represents can be one of three kinds:
|
|
*
|
|
* A Var: the slot represents a variable of this level that must be passed
|
|
* down because subqueries have outer references to it, or must be passed
|
|
* from a NestLoop node to its inner scan. The varlevelsup value in the Var
|
|
* will always be zero.
|
|
*
|
|
* A PlaceHolderVar: this works much like the Var case, except that the
|
|
* entry is a PlaceHolderVar node with a contained expression. The PHV
|
|
* will have phlevelsup = 0, and the contained expression is adjusted
|
|
* to match in level.
|
|
*
|
|
* An Aggref (with an expression tree representing its argument): the slot
|
|
* represents an aggregate expression that is an outer reference for some
|
|
* subquery. The Aggref itself has agglevelsup = 0, and its argument tree
|
|
* is adjusted to match in level.
|
|
*
|
|
* Note: we detect duplicate Var and PlaceHolderVar parameters and coalesce
|
|
* them into one slot, but we do not bother to do that for Aggrefs.
|
|
* The scope of duplicate-elimination only extends across the set of
|
|
* parameters passed from one query level into a single subquery, or for
|
|
* nestloop parameters across the set of nestloop parameters used in a single
|
|
* query level. So there is no possibility of a PARAM_EXEC slot being used
|
|
* for conflicting purposes.
|
|
*
|
|
* In addition, PARAM_EXEC slots are assigned for Params representing outputs
|
|
* from subplans (values that are setParam items for those subplans). These
|
|
* IDs need not be tracked via PlannerParamItems, since we do not need any
|
|
* duplicate-elimination nor later processing of the represented expressions.
|
|
* Instead, we just record the assignment of the slot number by appending to
|
|
* root->glob->paramExecTypes.
|
|
*/
|
|
typedef struct PlannerParamItem
|
|
{
|
|
pg_node_attr(no_copy_equal, no_read)
|
|
|
|
NodeTag type;
|
|
|
|
Node *item; /* the Var, PlaceHolderVar, or Aggref */
|
|
int paramId; /* its assigned PARAM_EXEC slot number */
|
|
} PlannerParamItem;
|
|
|
|
/*
|
|
* When making cost estimates for a SEMI/ANTI/inner_unique join, there are
|
|
* some correction factors that are needed in both nestloop and hash joins
|
|
* to account for the fact that the executor can stop scanning inner rows
|
|
* as soon as it finds a match to the current outer row. These numbers
|
|
* depend only on the selected outer and inner join relations, not on the
|
|
* particular paths used for them, so it's worthwhile to calculate them
|
|
* just once per relation pair not once per considered path. This struct
|
|
* is filled by compute_semi_anti_join_factors and must be passed along
|
|
* to the join cost estimation functions.
|
|
*
|
|
* outer_match_frac is the fraction of the outer tuples that are
|
|
* expected to have at least one match.
|
|
* match_count is the average number of matches expected for
|
|
* outer tuples that have at least one match.
|
|
*/
|
|
typedef struct SemiAntiJoinFactors
|
|
{
|
|
Selectivity outer_match_frac;
|
|
Selectivity match_count;
|
|
} SemiAntiJoinFactors;
|
|
|
|
/*
|
|
* Struct for extra information passed to subroutines of add_paths_to_joinrel
|
|
*
|
|
* restrictlist contains all of the RestrictInfo nodes for restriction
|
|
* clauses that apply to this join
|
|
* mergeclause_list is a list of RestrictInfo nodes for available
|
|
* mergejoin clauses in this join
|
|
* inner_unique is true if each outer tuple provably matches no more
|
|
* than one inner tuple
|
|
* sjinfo is extra info about special joins for selectivity estimation
|
|
* semifactors is as shown above (only valid for SEMI/ANTI/inner_unique joins)
|
|
* param_source_rels are OK targets for parameterization of result paths
|
|
*/
|
|
typedef struct JoinPathExtraData
|
|
{
|
|
List *restrictlist;
|
|
List *mergeclause_list;
|
|
bool inner_unique;
|
|
SpecialJoinInfo *sjinfo;
|
|
SemiAntiJoinFactors semifactors;
|
|
Relids param_source_rels;
|
|
} JoinPathExtraData;
|
|
|
|
/*
|
|
* Various flags indicating what kinds of grouping are possible.
|
|
*
|
|
* GROUPING_CAN_USE_SORT should be set if it's possible to perform
|
|
* sort-based implementations of grouping. When grouping sets are in use,
|
|
* this will be true if sorting is potentially usable for any of the grouping
|
|
* sets, even if it's not usable for all of them.
|
|
*
|
|
* GROUPING_CAN_USE_HASH should be set if it's possible to perform
|
|
* hash-based implementations of grouping.
|
|
*
|
|
* GROUPING_CAN_PARTIAL_AGG should be set if the aggregation is of a type
|
|
* for which we support partial aggregation (not, for example, grouping sets).
|
|
* It says nothing about parallel-safety or the availability of suitable paths.
|
|
*/
|
|
#define GROUPING_CAN_USE_SORT 0x0001
|
|
#define GROUPING_CAN_USE_HASH 0x0002
|
|
#define GROUPING_CAN_PARTIAL_AGG 0x0004
|
|
|
|
/*
|
|
* What kind of partitionwise aggregation is in use?
|
|
*
|
|
* PARTITIONWISE_AGGREGATE_NONE: Not used.
|
|
*
|
|
* PARTITIONWISE_AGGREGATE_FULL: Aggregate each partition separately, and
|
|
* append the results.
|
|
*
|
|
* PARTITIONWISE_AGGREGATE_PARTIAL: Partially aggregate each partition
|
|
* separately, append the results, and then finalize aggregation.
|
|
*/
|
|
typedef enum
|
|
{
|
|
PARTITIONWISE_AGGREGATE_NONE,
|
|
PARTITIONWISE_AGGREGATE_FULL,
|
|
PARTITIONWISE_AGGREGATE_PARTIAL
|
|
} PartitionwiseAggregateType;
|
|
|
|
/*
|
|
* Struct for extra information passed to subroutines of create_grouping_paths
|
|
*
|
|
* flags indicating what kinds of grouping are possible.
|
|
* partial_costs_set is true if the agg_partial_costs and agg_final_costs
|
|
* have been initialized.
|
|
* agg_partial_costs gives partial aggregation costs.
|
|
* agg_final_costs gives finalization costs.
|
|
* target_parallel_safe is true if target is parallel safe.
|
|
* havingQual gives list of quals to be applied after aggregation.
|
|
* targetList gives list of columns to be projected.
|
|
* patype is the type of partitionwise aggregation that is being performed.
|
|
*/
|
|
typedef struct
|
|
{
|
|
/* Data which remains constant once set. */
|
|
int flags;
|
|
bool partial_costs_set;
|
|
AggClauseCosts agg_partial_costs;
|
|
AggClauseCosts agg_final_costs;
|
|
|
|
/* Data which may differ across partitions. */
|
|
bool target_parallel_safe;
|
|
Node *havingQual;
|
|
List *targetList;
|
|
PartitionwiseAggregateType patype;
|
|
} GroupPathExtraData;
|
|
|
|
/*
|
|
* Struct for extra information passed to subroutines of grouping_planner
|
|
*
|
|
* limit_needed is true if we actually need a Limit plan node.
|
|
* limit_tuples is an estimated bound on the number of output tuples,
|
|
* or -1 if no LIMIT or couldn't estimate.
|
|
* count_est and offset_est are the estimated values of the LIMIT and OFFSET
|
|
* expressions computed by preprocess_limit() (see comments for
|
|
* preprocess_limit() for more information).
|
|
*/
|
|
typedef struct
|
|
{
|
|
bool limit_needed;
|
|
Cardinality limit_tuples;
|
|
int64 count_est;
|
|
int64 offset_est;
|
|
} FinalPathExtraData;
|
|
|
|
/*
|
|
* For speed reasons, cost estimation for join paths is performed in two
|
|
* phases: the first phase tries to quickly derive a lower bound for the
|
|
* join cost, and then we check if that's sufficient to reject the path.
|
|
* If not, we come back for a more refined cost estimate. The first phase
|
|
* fills a JoinCostWorkspace struct with its preliminary cost estimates
|
|
* and possibly additional intermediate values. The second phase takes
|
|
* these values as inputs to avoid repeating work.
|
|
*
|
|
* (Ideally we'd declare this in cost.h, but it's also needed in pathnode.h,
|
|
* so seems best to put it here.)
|
|
*/
|
|
typedef struct JoinCostWorkspace
|
|
{
|
|
/* Preliminary cost estimates --- must not be larger than final ones! */
|
|
Cost startup_cost; /* cost expended before fetching any tuples */
|
|
Cost total_cost; /* total cost (assuming all tuples fetched) */
|
|
|
|
/* Fields below here should be treated as private to costsize.c */
|
|
Cost run_cost; /* non-startup cost components */
|
|
|
|
/* private for cost_nestloop code */
|
|
Cost inner_run_cost; /* also used by cost_mergejoin code */
|
|
Cost inner_rescan_run_cost;
|
|
|
|
/* private for cost_mergejoin code */
|
|
Cardinality outer_rows;
|
|
Cardinality inner_rows;
|
|
Cardinality outer_skip_rows;
|
|
Cardinality inner_skip_rows;
|
|
|
|
/* private for cost_hashjoin code */
|
|
int numbuckets;
|
|
int numbatches;
|
|
Cardinality inner_rows_total;
|
|
} JoinCostWorkspace;
|
|
|
|
/*
|
|
* AggInfo holds information about an aggregate that needs to be computed.
|
|
* Multiple Aggrefs in a query can refer to the same AggInfo by having the
|
|
* same 'aggno' value, so that the aggregate is computed only once.
|
|
*/
|
|
typedef struct AggInfo
|
|
{
|
|
pg_node_attr(no_copy_equal, no_read)
|
|
|
|
NodeTag type;
|
|
|
|
/*
|
|
* List of Aggref exprs that this state value is for.
|
|
*
|
|
* There will always be at least one, but there can be multiple identical
|
|
* Aggref's sharing the same per-agg.
|
|
*/
|
|
List *aggrefs;
|
|
|
|
/* Transition state number for this aggregate */
|
|
int transno;
|
|
|
|
/*
|
|
* "shareable" is false if this agg cannot share state values with other
|
|
* aggregates because the final function is read-write.
|
|
*/
|
|
bool shareable;
|
|
|
|
/* Oid of the final function, or InvalidOid if none */
|
|
Oid finalfn_oid;
|
|
} AggInfo;
|
|
|
|
/*
|
|
* AggTransInfo holds information about transition state that is used by one
|
|
* or more aggregates in the query. Multiple aggregates can share the same
|
|
* transition state, if they have the same inputs and the same transition
|
|
* function. Aggrefs that share the same transition info have the same
|
|
* 'aggtransno' value.
|
|
*/
|
|
typedef struct AggTransInfo
|
|
{
|
|
pg_node_attr(no_copy_equal, no_read)
|
|
|
|
NodeTag type;
|
|
|
|
/* Inputs for this transition state */
|
|
List *args;
|
|
Expr *aggfilter;
|
|
|
|
/* Oid of the state transition function */
|
|
Oid transfn_oid;
|
|
|
|
/* Oid of the serialization function, or InvalidOid if none */
|
|
Oid serialfn_oid;
|
|
|
|
/* Oid of the deserialization function, or InvalidOid if none */
|
|
Oid deserialfn_oid;
|
|
|
|
/* Oid of the combine function, or InvalidOid if none */
|
|
Oid combinefn_oid;
|
|
|
|
/* Oid of state value's datatype */
|
|
Oid aggtranstype;
|
|
|
|
/* Additional data about transtype */
|
|
int32 aggtranstypmod;
|
|
int transtypeLen;
|
|
bool transtypeByVal;
|
|
|
|
/* Space-consumption estimate */
|
|
int32 aggtransspace;
|
|
|
|
/* Initial value from pg_aggregate entry */
|
|
Datum initValue pg_node_attr(read_write_ignore);
|
|
bool initValueIsNull;
|
|
} AggTransInfo;
|
|
|
|
#endif /* PATHNODES_H */
|