* Definitions for planner's internal data structures.
*
*
- * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/include/nodes/relation.h
#define RELATION_H
#include "access/sdir.h"
+#include "lib/stringinfo.h"
#include "nodes/params.h"
#include "nodes/parsenodes.h"
#include "storage/block.h"
/*
* Costing aggregate function execution requires these statistics about
- * the aggregates to be executed by a given Agg node. Note that transCost
- * includes the execution costs of the aggregates' input expressions.
+ * the aggregates to be executed by a given Agg node. Note that the costs
+ * include the execution costs of the aggregates' argument expressions as
+ * well as the aggregate functions themselves.
*/
typedef struct AggClauseCosts
{
int numAggs; /* total number of aggregate functions */
- int numOrderedAggs; /* number that use DISTINCT or ORDER BY */
+ int numOrderedAggs; /* number w/ DISTINCT/ORDER BY/WITHIN GROUP */
QualCost transCost; /* total per-input-row execution costs */
- Cost finalCost; /* total costs of agg final functions */
+ Cost finalCost; /* total per-aggregated-row costs */
Size transitionSpace; /* space for pass-by-ref transition data */
} AggClauseCosts;
Index lastRowMarkId; /* highest PlanRowMark ID assigned */
+ int lastPlanNodeId; /* highest plan node ID assigned */
+
bool transientPlan; /* redo plan when TransactionXmin changes? */
+
+ bool hasRowSecurity; /* row security applied? */
+
+ bool parallelModeOK; /* parallel mode potentially OK? */
+
+ bool parallelModeNeeded; /* parallel mode actually required? */
} PlannerGlobal;
/* macro for fetching the Plan associated with a SubPlan node */
*
* This struct is conventionally called "root" in all the planner routines.
* It holds links to all of the planner's working state, in addition to the
- * original Query. Note that at present the planner extensively modifies
+ * original Query. Note that at present the planner extensively modifies
* the passed-in Query data structure; someday that should stop.
*----------
*/
struct PlannerInfo *parent_root; /* NULL at outermost Query */
+ /*
+ * plan_params contains the expressions that this query level needs to
+ * make available to a lower query level that is currently being planned.
+ * outer_params contains the paramIds of PARAM_EXEC Params that outer
+ * query levels will make available to this query level.
+ */
List *plan_params; /* list of PlannerParamItems, see below */
+ Bitmapset *outer_params;
/*
* simple_rel_array holds pointers to "base rels" and "other rels" (see
- * comments for RelOptInfo for more info). It is indexed by rangetable
+ * comments for RelOptInfo for more info). It is indexed by rangetable
* index (so entry 0 is always wasted). Entries can be NULL when an RTE
* does not correspond to a base relation, such as a join RTE or an
* unreferenced view RTE; or if the RelOptInfo hasn't been made yet.
/*
* all_baserels is a Relids set of all base relids (but not "other"
* relids) in the query; that is, the Relids identifier of the final join
- * we need to form.
+ * we need to form. This is computed in make_one_rel, just before we
+ * start making Paths.
*/
Relids all_baserels;
+ /*
+ * nullable_baserels is a Relids set of base relids that are nullable by
+ * some outer join in the jointree; these are rels that are potentially
+ * nullable below the WHERE clause, SELECT targetlist, etc. This is
+ * computed in deconstruct_jointree.
+ */
+ Relids nullable_baserels;
+
/*
* join_rel_list is a list of all join-relation RelOptInfos we have
* considered in this planning run. For small problems we just scan the
* list to do lookups, but when there are many join relations we build a
* hash table for faster lookups. The hash table is present and valid
- * when join_rel_hash is not NULL. Note that we still maintain the list
+ * when join_rel_hash is not NULL. Note that we still maintain the list
* even when using the hash table for lookups; this simplifies life for
* GEQO.
*/
List *cte_plan_ids; /* per-CTE-item list of subplan IDs */
+ List *multiexpr_params; /* List of Lists of Params for
+ * MULTIEXPR subquery outputs */
+
List *eq_classes; /* list of active EquivalenceClasses */
List *canon_pathkeys; /* list of "canonical" PathKeys */
List *full_join_clauses; /* list of RestrictInfos for
* mergejoinable full join clauses */
- List *join_info_list; /* list of SpecialJoinInfos */
+ List *join_info_list; /* list of SpecialJoinInfos */
- List *lateral_info_list; /* list of LateralJoinInfos */
+ List *lateral_info_list; /* list of LateralJoinInfos */
List *append_rel_list; /* list of AppendRelInfos */
List *placeholder_list; /* list of PlaceHolderInfos */
List *query_pathkeys; /* desired pathkeys for query_planner(), and
- * actual pathkeys afterwards */
+ * actual pathkeys after planning */
List *group_pathkeys; /* groupClause pathkeys, if any */
List *window_pathkeys; /* pathkeys of bottom window, if any */
bool hasInheritedTarget; /* true if parse->resultRelation is an
* inheritance child rel */
bool hasJoinRTEs; /* true if any RTEs are RTE_JOIN kind */
- bool hasLateralRTEs; /* true if any RTEs are marked LATERAL */
+ bool hasLateralRTEs; /* true if any RTEs are marked LATERAL */
+ bool hasDeletedRTEs; /* true if any RTE was deleted from jointree */
bool hasHavingQual; /* true if havingQual was non-null */
bool hasPseudoConstantQuals; /* true if any RestrictInfo has
* pseudoconstant = true */
/* optional private data for join_search_hook, e.g., GEQO */
void *join_search_private;
+
+ /* for GroupingFunc fixup in setrefs */
+ AttrNumber *grouping_map;
} PlannerInfo;
* 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
+ * 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
* alias Vars are expanded to non-aliased form during preprocess_expression.
*
* Parts of this data structure are specific to various scan and join
- * mechanisms. It didn't seem worth creating new node types for them.
+ * 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
* clauses have been applied (ie, output rows of a plan for it)
* width - avg. number of bytes per tuple in the relation after the
* appropriate projections have been done (ie, output width)
- * consider_startup - true if there is any value in keeping paths for
+ * 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
* reltargetlist - List of 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
* Vars and PlaceHolderVars)
* lateral_relids - required outer rels for LATERAL, as a Relids set
* (for child rels this can be more than lateral_vars)
+ * lateral_referencers - relids of rels that reference this one laterally
* 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)
* subplan - plan for subquery (NULL if it's not a subquery)
* subroot - PlannerInfo for subquery (NULL if it's not a subquery)
* subplan_params - list of PlannerParamItems to be passed to subquery
- * fdwroutine - function hooks for FDW, if foreign table (else NULL)
- * fdw_private - private state for FDW, if foreign table (else NULL)
*
* Note: for a subquery, tuples, subplan, subroot are not set immediately
* upon creation of the RelOptInfo object; they are filled in when
- * set_subquery_pathlist processes the object. Likewise, fdwroutine
- * and fdw_private are filled during initial path creation.
+ * set_subquery_pathlist processes the object.
*
* For otherrels that are appendrel members, these fields are filled
* in just as for a baserel.
*
+ * If the relation is either a foreign table or a join of foreign tables that
+ * all belong to the same foreign server, these fields will be set:
+ *
+ * serverid - OID of foreign server, if foreign table (else InvalidOid)
+ * fdwroutine - function hooks for FDW, if foreign table (else NULL)
+ * fdw_private - private state for FDW, if foreign table (else NULL)
+ *
* The presence of the remaining fields depends on the restrictions
* and joins that the relation participates in:
*
int width; /* estimated avg width of result tuples */
/* per-relation planner control flags */
- bool consider_startup; /* keep cheap-startup-cost paths? */
+ bool consider_startup; /* keep cheap-startup-cost paths? */
+ bool consider_param_startup; /* ditto, for parameterized paths? */
/* materialization information */
List *reltargetlist; /* Vars to be output by scan of relation */
Relids *attr_needed; /* array indexed [min_attr .. max_attr] */
int32 *attr_widths; /* array indexed [min_attr .. max_attr] */
List *lateral_vars; /* LATERAL Vars and PHVs referenced by rel */
- Relids lateral_relids; /* minimum parameterization of rel */
+ Relids lateral_relids; /* minimum parameterization of rel */
+ Relids lateral_referencers; /* rels that reference me laterally */
List *indexlist; /* list of IndexOptInfo */
BlockNumber pages; /* size estimates derived from pg_class */
double tuples;
/* use "struct Plan" to avoid including plannodes.h here */
struct Plan *subplan; /* if subquery */
PlannerInfo *subroot; /* if subquery */
- List *subplan_params; /* if subquery */
+ List *subplan_params; /* if subquery */
+
+ /* Information about foreign tables and foreign joins */
+ Oid serverid; /* identifies server for the table or join */
/* use "struct FdwRoutine" to avoid including fdwapi.h here */
- struct FdwRoutine *fdwroutine; /* if foreign table */
- void *fdw_private; /* if foreign table */
+ struct FdwRoutine *fdwroutine;
+ void *fdw_private;
/* used by various scans and joins: */
List *baserestrictinfo; /* RestrictInfo structures (if base
Oid reltablespace; /* tablespace of index (not table) */
RelOptInfo *rel; /* back-link to index's table */
- /* statistics from pg_class */
+ /* index-size statistics (from pg_class and elsewhere) */
BlockNumber pages; /* number of disk pages in index */
double tuples; /* number of index tuples in index */
+ int tree_height; /* index tree height, or -1 if unknown */
/* index descriptor information */
int ncolumns; /* number of columns in index */
Oid *sortopfamily; /* OIDs of btree opfamilies, if orderable */
bool *reverse_sort; /* is sort order descending? */
bool *nulls_first; /* do NULLs come first in the sort order? */
+ bool *canreturn; /* which index cols can be returned in an
+ * index-only scan? */
Oid relam; /* OID of the access method (in pg_am) */
RegProcedure amcostestimate; /* OID of the access method's cost fcn */
bool unique; /* true if a unique index */
bool immediate; /* is uniqueness enforced immediately? */
bool hypothetical; /* true if index doesn't really exist */
- bool canreturn; /* can index return IndexTuples? */
bool amcanorderbyop; /* does AM support order by operator result? */
bool amoptionalkey; /* can query omit key for the first column? */
bool amsearcharray; /* can AM handle ScalarArrayOpExpr quals? */
* 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
+ * 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
* 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
+ * 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
* 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.
+ * 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.
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 */
+ 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 */
*
* 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
+ * 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
*
* 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
+ * 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
* information.)
*
* Note: pk_strategy is either BTLessStrategyNumber (for ASC) or
- * BTGreaterStrategyNumber (for DESC). We assume that all ordering-capable
+ * BTGreaterStrategyNumber (for DESC). We assume that all ordering-capable
* index types will use btree-compatible strategy numbers.
*/
typedef struct PathKey
* "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
+ * 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).
*
*
* 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
+ * 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
/*
* ForeignPath represents a potential scan of a foreign table
*
- * fdw_private stores FDW private data about the scan. While fdw_private is
+ * 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
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 CustomPath;
+
+#define CUSTOMPATH_SUPPORT_BACKWARD_SCAN 0x0001
+#define CUSTOMPATH_SUPPORT_MARK_RESTORE 0x0002
+
+typedef struct CustomPathMethods
+{
+ const char *CustomName;
+
+ /* Convert Path to a Plan */
+ struct Plan *(*PlanCustomPath) (PlannerInfo *root,
+ RelOptInfo *rel,
+ struct CustomPath *best_path,
+ List *tlist,
+ List *clauses,
+ List *custom_plans);
+ /* Optional: print additional fields besides "private" */
+ void (*TextOutCustomPath) (StringInfo str,
+ const struct CustomPath *node);
+} CustomPathMethods;
+
+typedef struct CustomPath
+{
+ Path path;
+ uint32 flags; /* mask of CUSTOMPATH_* flags, see above */
+ List *custom_paths; /* list of child Path nodes, if any */
+ List *custom_private;
+ const CustomPathMethods *methods;
+} CustomPath;
+
/*
* AppendPath represents an Append plan, ie, successive execution of
* several member plans.
*
* This is unlike the other Path nodes in that it can actually generate
* different plans: either hash-based or sort-based implementation, or a
- * no-op if the input path can be proven distinct already. The decision
+ * 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
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 */
+ int num_workers; /* number of workers sought to help */
+ bool single_copy; /* path must not be executed >1x */
+} GatherPath;
+
/*
* All join-type paths share these fields.
*/
* 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
+ * 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
* 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
+ * 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?)
+ * conditions. Possibly we should rename it to reflect that meaning?)
*
* RestrictInfo nodes also contain an outerjoin_delayed flag, which is true
* if the clause's applicability must be delayed due to any outer joins
* outer join(s). A clause that is not outerjoin_delayed can be enforced
* anywhere it is computable.
*
- * In general, the referenced clause might be arbitrarily complex. The
+ * 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
*
* 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
+ * 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
*
* 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
+ * 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.
*/
/*
* 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
+ * 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
* "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
+ * 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
+ * SpecialJoinInfo struct. These structs are kept in the PlannerInfo node's
* join_info_list.
*
* Similarly, semijoins and antijoins created by flattening IN (subselect)
* 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.)
+ * pushed-down clause. (We don't track this for FULL JOINs, either.)
*
- * join_quals is an implicit-AND list of the quals syntactically associated
- * with the join (they may or may not end up being applied at the join level).
- * This is just a side list and does not drive actual application of quals.
- * For JOIN_SEMI joins, this is cleared to NIL in create_unique_path() if
- * the join is found not to be suitable for a uniqueify-the-RHS plan.
+ * 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
* 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
- * join_quals are not set meaningfully within such structs.
+ * of course the semi_xxx fields are not set meaningfully within such structs.
*/
typedef struct SpecialJoinInfo
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 */
- List *join_quals; /* join quals, in implicit-AND list format */
+ /* 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 */
} SpecialJoinInfo;
/*
* "Lateral join" info.
*
- * Lateral references in subqueries constrain the join order in a way that's
- * somewhat like outer joins, though different in detail. We construct one or
- * more LateralJoinInfos for each RTE with lateral references, and add them to
- * the PlannerInfo node's lateral_info_list.
+ * Lateral references constrain the join order in a way that's somewhat like
+ * outer joins, though different in detail. We construct a LateralJoinInfo
+ * for each lateral cross-reference, placing them in the PlannerInfo node's
+ * lateral_info_list.
*
- * lateral_rhs is the relid of a baserel with lateral references, and
- * lateral_lhs is a set of relids of baserels it references, all of which
- * must be present on the LHS to compute a parameter needed by the RHS.
- * Typically, lateral_lhs is a singleton, but it can include multiple rels
- * if the RHS references a PlaceHolderVar with a multi-rel ph_eval_at level.
- * We disallow joining to only part of the LHS in such cases, since that would
- * result in a join tree with no convenient place to compute the PHV.
+ * For unflattened LATERAL RTEs, we generate LateralJoinInfo(s) in which
+ * lateral_rhs is the relid of the LATERAL baserel, and lateral_lhs is a set
+ * of relids of baserels it references, all of which must be present on the
+ * LHS to compute a parameter needed by the RHS. Typically, lateral_lhs is
+ * a singleton, but it can include multiple rels if the RHS references a
+ * PlaceHolderVar with a multi-rel ph_eval_at level. We disallow joining to
+ * only part of the LHS in such cases, since that would result in a join tree
+ * with no convenient place to compute the PHV.
*
* When an appendrel contains lateral references (eg "LATERAL (SELECT x.col1
* UNION ALL SELECT y.col2)"), the LateralJoinInfos reference the parent
* baserel not the member otherrels, since it is the parent relid that is
* considered for joining purposes.
+ *
+ * If any LATERAL RTEs were flattened into the parent query, it is possible
+ * that the query now contains PlaceHolderVars containing lateral references,
+ * representing expressions that need to be evaluated at particular spots in
+ * the jointree but contain lateral references to Vars from elsewhere. These
+ * give rise to LateralJoinInfos in which lateral_rhs is the evaluation point
+ * of a PlaceHolderVar and lateral_lhs is the set of lateral rels it needs.
*/
typedef struct LateralJoinInfo
{
NodeTag type;
- Index lateral_rhs; /* a baserel containing lateral refs */
- Relids lateral_lhs; /* some base relids it references */
+ Relids lateral_lhs; /* rels needed to compute a lateral value */
+ Relids lateral_rhs; /* rel where lateral value is needed */
} LateralJoinInfo;
/*
/*
* 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
+ * 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 */
* 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
+ * 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
+ * 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 */
* 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
+ * 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.
* 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.
*
- * ph_may_need is an initial estimate of ph_needed, formed using the
- * syntactic locations of references to the PHV. We need this in order to
- * determine whether the PHV reference forces a join ordering constraint:
- * if the PHV has to be evaluated below the nullable side of an outer join,
- * and then used above that outer join, we must constrain join order to ensure
- * there's a valid place to evaluate the PHV below the join. The final
- * actual ph_needed level might be lower than ph_may_need, but we can't
- * determine that until later on. Fortunately this doesn't matter for what
- * we need ph_may_need for: if there's a PHV reference syntactically
- * above the outer join, it's not going to be allowed to drop below the outer
- * join, so we would come to the same conclusions about join order even if
- * we had the final ph_needed value to compare to.
+ * 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
Index phid; /* ID for PH (unique within planner run) */
PlaceHolderVar *ph_var; /* copy of PlaceHolderVar tree */
Relids ph_eval_at; /* lowest level we can evaluate value at */
+ Relids ph_lateral; /* relids of contained lateral refs, if any */
Relids ph_needed; /* highest level the value is needed at */
- Relids ph_may_need; /* highest level it might be needed at */
int32 ph_width; /* estimated attribute width */
} PlaceHolderInfo;
* 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
+ * 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.
*
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
+ * sjinfo is extra info about special joins for selectivity estimation
+ * semifactors is as shown above (only valid for SEMI or ANTI joins)
+ * param_source_rels are OK targets for parameterization of result paths
+ * extra_lateral_rels are additional parameterization for result paths
+ */
+typedef struct JoinPathExtraData
+{
+ List *restrictlist;
+ List *mergeclause_list;
+ SpecialJoinInfo *sjinfo;
+ SemiAntiJoinFactors semifactors;
+ Relids param_source_rels;
+ Relids extra_lateral_rels;
+} JoinPathExtraData;
+
/*
* 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
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;
- double outer_matched_rows;
- Selectivity inner_scan_frac;
/* private for cost_mergejoin code */
- Cost inner_run_cost;
double outer_rows;
double inner_rows;
double outer_skip_rows;
projects / postgresql / blobdiff