/*-------------------------------------------------------------------------
*
- * relnode.c--
- * Relation manipulation routines
+ * relnode.c
+ * Relation-node lookup/construction routines
*
- * Copyright (c) 1994, Regents of the University of California
+ * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/optimizer/util/relnode.c,v 1.6 1998/07/18 04:22:41 momjian Exp $
+ * src/backend/optimizer/util/relnode.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
-#include "nodes/relation.h"
-
-#include "optimizer/internal.h"
-#include "optimizer/pathnode.h" /* where the decls go */
+#include "optimizer/cost.h"
+#include "optimizer/pathnode.h"
+#include "optimizer/paths.h"
+#include "optimizer/placeholder.h"
#include "optimizer/plancat.h"
+#include "optimizer/restrictinfo.h"
+#include "parser/parsetree.h"
+#include "utils/hsearch.h"
+
+typedef struct JoinHashEntry
+{
+ Relids join_relids; /* hash key --- MUST BE FIRST */
+ RelOptInfo *join_rel;
+} JoinHashEntry;
+
+static void build_joinrel_tlist(PlannerInfo *root, RelOptInfo *joinrel,
+ RelOptInfo *input_rel);
+static List *build_joinrel_restrictlist(PlannerInfo *root,
+ RelOptInfo *joinrel,
+ RelOptInfo *outer_rel,
+ RelOptInfo *inner_rel);
+static void build_joinrel_joinlist(RelOptInfo *joinrel,
+ RelOptInfo *outer_rel,
+ RelOptInfo *inner_rel);
+static List *subbuild_joinrel_restrictlist(RelOptInfo *joinrel,
+ List *joininfo_list,
+ List *new_restrictlist);
+static List *subbuild_joinrel_joinlist(RelOptInfo *joinrel,
+ List *joininfo_list,
+ List *new_joininfo);
/*
- * get_base_rel--
- * Returns relation entry corresponding to 'relid', creating a new one if
- * necessary. This is for base relations.
- *
+ * build_simple_rel
+ * Construct a new RelOptInfo for a base relation or 'other' relation.
*/
RelOptInfo *
-get_base_rel(Query *root, int relid)
+build_simple_rel(PlannerInfo *root, int relid, RelOptKind reloptkind)
{
- List *relids;
- RelOptInfo *rel;
+ RelOptInfo *rel;
+ RangeTblEntry *rte;
- relids = lconsi(relid, NIL);
- rel = rel_member(relids, root->base_relation_list_);
- if (rel == NULL)
- {
- rel = makeNode(RelOptInfo);
- rel->relids = relids;
- rel->indexed = false;
- rel->pages = 0;
- rel->tuples = 0;
- rel->width = 0;
- rel->targetlist = NIL;
- rel->pathlist = NIL;
- rel->unorderedpath = (Path *) NULL;
- rel->cheapestpath = (Path *) NULL;
- rel->pruneable = true;
- rel->classlist = NULL;
- rel->ordering = NULL;
- rel->relam = InvalidOid;
- rel->clauseinfo = NIL;
- rel->joininfo = NIL;
- rel->innerjoin = NIL;
- rel->superrels = NIL;
-
- root->base_relation_list_ = lcons(rel,
- root->base_relation_list_);
+ /* Rel should not exist already */
+ Assert(relid > 0 && relid < root->simple_rel_array_size);
+ if (root->simple_rel_array[relid] != NULL)
+ elog(ERROR, "rel %d already exists", relid);
- /*
- * ??? the old lispy C code (get_rel) do a listp(relid) here but
- * that can never happen since we already established relid is not
- * a list. -ay 10/94
- */
- if (relid < 0)
- {
+ /* Fetch RTE for relation */
+ rte = root->simple_rte_array[relid];
+ Assert(rte != NULL);
+
+ rel = makeNode(RelOptInfo);
+ rel->reloptkind = reloptkind;
+ rel->relids = bms_make_singleton(relid);
+ rel->rows = 0;
+ rel->width = 0;
+ rel->reltargetlist = NIL;
+ rel->pathlist = NIL;
+ rel->cheapest_startup_path = NULL;
+ rel->cheapest_total_path = NULL;
+ rel->cheapest_unique_path = NULL;
+ rel->relid = relid;
+ rel->rtekind = rte->rtekind;
+ /* min_attr, max_attr, attr_needed, attr_widths are set below */
+ rel->indexlist = NIL;
+ rel->pages = 0;
+ rel->tuples = 0;
+ rel->subplan = NULL;
+ rel->subrtable = NIL;
+ rel->subrowmark = NIL;
+ rel->baserestrictinfo = NIL;
+ rel->baserestrictcost.startup = 0;
+ rel->baserestrictcost.per_tuple = 0;
+ rel->joininfo = NIL;
+ rel->has_eclass_joins = false;
+ rel->index_outer_relids = NULL;
+ rel->index_inner_paths = NIL;
+
+ /* Check type of rtable entry */
+ switch (rte->rtekind)
+ {
+ case RTE_RELATION:
+ /* Table --- retrieve statistics from the system catalogs */
+ get_relation_info(root, rte->relid, rte->inh, rel);
+ break;
+ case RTE_SUBQUERY:
+ case RTE_FUNCTION:
+ case RTE_VALUES:
+ case RTE_CTE:
/*
- * If the relation is a materialized relation, assume
- * constants for sizes.
+ * Subquery, function, or values list --- set up attr range and
+ * arrays
+ *
+ * Note: 0 is included in range to support whole-row Vars
*/
- rel->pages = _TEMP_RELATION_PAGES_;
- rel->tuples = _TEMP_RELATION_TUPLES_;
+ rel->min_attr = 0;
+ rel->max_attr = list_length(rte->eref->colnames);
+ rel->attr_needed = (Relids *)
+ palloc0((rel->max_attr - rel->min_attr + 1) * sizeof(Relids));
+ rel->attr_widths = (int32 *)
+ palloc0((rel->max_attr - rel->min_attr + 1) * sizeof(int32));
+ break;
+ default:
+ elog(ERROR, "unrecognized RTE kind: %d",
+ (int) rte->rtekind);
+ break;
+ }
- }
- else
+ /* Save the finished struct in the query's simple_rel_array */
+ root->simple_rel_array[relid] = rel;
+
+ /*
+ * If this rel is an appendrel parent, recurse to build "other rel"
+ * RelOptInfos for its children. They are "other rels" because they are
+ * not in the main join tree, but we will need RelOptInfos to plan access
+ * to them.
+ */
+ if (rte->inh)
+ {
+ ListCell *l;
+
+ foreach(l, root->append_rel_list)
{
- bool hasindex;
- int pages,
- tuples;
+ AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
- /*
- * Otherwise, retrieve relation characteristics from the
- * system catalogs.
- */
- relation_info(root, relid, &hasindex, &pages, &tuples);
- rel->indexed = hasindex;
- rel->pages = pages;
- rel->tuples = tuples;
+ /* append_rel_list contains all append rels; ignore others */
+ if (appinfo->parent_relid != relid)
+ continue;
+
+ (void) build_simple_rel(root, appinfo->child_relid,
+ RELOPT_OTHER_MEMBER_REL);
}
}
+
return rel;
}
/*
- * get_join_rel--
- * Returns relation entry corresponding to 'relid' (a list of relids),
- * creating a new one if necessary. This is for join relations.
- *
+ * find_base_rel
+ * Find a base or other relation entry, which must already exist.
+ */
+RelOptInfo *
+find_base_rel(PlannerInfo *root, int relid)
+{
+ RelOptInfo *rel;
+
+ Assert(relid > 0);
+
+ if (relid < root->simple_rel_array_size)
+ {
+ rel = root->simple_rel_array[relid];
+ if (rel)
+ return rel;
+ }
+
+ elog(ERROR, "no relation entry for relid %d", relid);
+
+ return NULL; /* keep compiler quiet */
+}
+
+/*
+ * build_join_rel_hash
+ * Construct the auxiliary hash table for join relations.
+ */
+static void
+build_join_rel_hash(PlannerInfo *root)
+{
+ HTAB *hashtab;
+ HASHCTL hash_ctl;
+ ListCell *l;
+
+ /* Create the hash table */
+ MemSet(&hash_ctl, 0, sizeof(hash_ctl));
+ hash_ctl.keysize = sizeof(Relids);
+ hash_ctl.entrysize = sizeof(JoinHashEntry);
+ hash_ctl.hash = bitmap_hash;
+ hash_ctl.match = bitmap_match;
+ hash_ctl.hcxt = CurrentMemoryContext;
+ hashtab = hash_create("JoinRelHashTable",
+ 256L,
+ &hash_ctl,
+ HASH_ELEM | HASH_FUNCTION | HASH_COMPARE | HASH_CONTEXT);
+
+ /* Insert all the already-existing joinrels */
+ foreach(l, root->join_rel_list)
+ {
+ RelOptInfo *rel = (RelOptInfo *) lfirst(l);
+ JoinHashEntry *hentry;
+ bool found;
+
+ hentry = (JoinHashEntry *) hash_search(hashtab,
+ &(rel->relids),
+ HASH_ENTER,
+ &found);
+ Assert(!found);
+ hentry->join_rel = rel;
+ }
+
+ root->join_rel_hash = hashtab;
+}
+
+/*
+ * find_join_rel
+ * Returns relation entry corresponding to 'relids' (a set of RT indexes),
+ * or NULL if none exists. This is for join relations.
*/
RelOptInfo *
-get_join_rel(Query *root, List *relid)
+find_join_rel(PlannerInfo *root, Relids relids)
{
- return rel_member(relid, root->join_relation_list_);
+ /*
+ * Switch to using hash lookup when list grows "too long". The threshold
+ * is arbitrary and is known only here.
+ */
+ if (!root->join_rel_hash && list_length(root->join_rel_list) > 32)
+ build_join_rel_hash(root);
+
+ /*
+ * Use either hashtable lookup or linear search, as appropriate.
+ *
+ * Note: the seemingly redundant hashkey variable is used to avoid taking
+ * the address of relids; unless the compiler is exceedingly smart, doing
+ * so would force relids out of a register and thus probably slow down the
+ * list-search case.
+ */
+ if (root->join_rel_hash)
+ {
+ Relids hashkey = relids;
+ JoinHashEntry *hentry;
+
+ hentry = (JoinHashEntry *) hash_search(root->join_rel_hash,
+ &hashkey,
+ HASH_FIND,
+ NULL);
+ if (hentry)
+ return hentry->join_rel;
+ }
+ else
+ {
+ ListCell *l;
+
+ foreach(l, root->join_rel_list)
+ {
+ RelOptInfo *rel = (RelOptInfo *) lfirst(l);
+
+ if (bms_equal(rel->relids, relids))
+ return rel;
+ }
+ }
+
+ return NULL;
}
/*
- * rel-member--
- * Determines whether a relation of id 'relid' is contained within a list
- * 'rels'.
+ * build_join_rel
+ * Returns relation entry corresponding to the union of two given rels,
+ * creating a new relation entry if none already exists.
*
- * Returns the corresponding entry in 'rels' if it is there.
+ * 'joinrelids' is the Relids set that uniquely identifies the join
+ * 'outer_rel' and 'inner_rel' are relation nodes for the relations to be
+ * joined
+ * 'sjinfo': join context info
+ * 'restrictlist_ptr': result variable. If not NULL, *restrictlist_ptr
+ * receives the list of RestrictInfo nodes that apply to this
+ * particular pair of joinable relations.
*
+ * restrictlist_ptr makes the routine's API a little grotty, but it saves
+ * duplicated calculation of the restrictlist...
*/
RelOptInfo *
-rel_member(List *relid, List *rels)
+build_join_rel(PlannerInfo *root,
+ Relids joinrelids,
+ RelOptInfo *outer_rel,
+ RelOptInfo *inner_rel,
+ SpecialJoinInfo *sjinfo,
+ List **restrictlist_ptr)
{
- List *temp = NIL;
- List *temprelid = NIL;
+ RelOptInfo *joinrel;
+ List *restrictlist;
+
+ /*
+ * See if we already have a joinrel for this set of base rels.
+ */
+ joinrel = find_join_rel(root, joinrelids);
+
+ if (joinrel)
+ {
+ /*
+ * Yes, so we only need to figure the restrictlist for this particular
+ * pair of component relations.
+ */
+ if (restrictlist_ptr)
+ *restrictlist_ptr = build_joinrel_restrictlist(root,
+ joinrel,
+ outer_rel,
+ inner_rel);
+ return joinrel;
+ }
+
+ /*
+ * Nope, so make one.
+ */
+ joinrel = makeNode(RelOptInfo);
+ joinrel->reloptkind = RELOPT_JOINREL;
+ joinrel->relids = bms_copy(joinrelids);
+ joinrel->rows = 0;
+ joinrel->width = 0;
+ joinrel->reltargetlist = NIL;
+ joinrel->pathlist = NIL;
+ joinrel->cheapest_startup_path = NULL;
+ joinrel->cheapest_total_path = NULL;
+ joinrel->cheapest_unique_path = NULL;
+ joinrel->relid = 0; /* indicates not a baserel */
+ joinrel->rtekind = RTE_JOIN;
+ joinrel->min_attr = 0;
+ joinrel->max_attr = 0;
+ joinrel->attr_needed = NULL;
+ joinrel->attr_widths = NULL;
+ joinrel->indexlist = NIL;
+ joinrel->pages = 0;
+ joinrel->tuples = 0;
+ joinrel->subplan = NULL;
+ joinrel->subrtable = NIL;
+ joinrel->subrowmark = NIL;
+ joinrel->baserestrictinfo = NIL;
+ joinrel->baserestrictcost.startup = 0;
+ joinrel->baserestrictcost.per_tuple = 0;
+ joinrel->joininfo = NIL;
+ joinrel->has_eclass_joins = false;
+ joinrel->index_outer_relids = NULL;
+ joinrel->index_inner_paths = NIL;
+
+ /*
+ * Create a new tlist containing just the vars that need to be output from
+ * this join (ie, are needed for higher joinclauses or final output).
+ *
+ * NOTE: the tlist order for a join rel will depend on which pair of outer
+ * and inner rels we first try to build it from. But the contents should
+ * be the same regardless.
+ */
+ build_joinrel_tlist(root, joinrel, outer_rel);
+ build_joinrel_tlist(root, joinrel, inner_rel);
+ add_placeholders_to_joinrel(root, joinrel);
- if (relid != NIL && rels != NIL)
+ /*
+ * Construct restrict and join clause lists for the new joinrel. (The
+ * caller might or might not need the restrictlist, but I need it anyway
+ * for set_joinrel_size_estimates().)
+ */
+ restrictlist = build_joinrel_restrictlist(root, joinrel,
+ outer_rel, inner_rel);
+ if (restrictlist_ptr)
+ *restrictlist_ptr = restrictlist;
+ build_joinrel_joinlist(joinrel, outer_rel, inner_rel);
+
+ /*
+ * This is also the right place to check whether the joinrel has any
+ * pending EquivalenceClass joins.
+ */
+ joinrel->has_eclass_joins = has_relevant_eclass_joinclause(root, joinrel);
+
+ /*
+ * Set estimates of the joinrel's size.
+ */
+ set_joinrel_size_estimates(root, joinrel, outer_rel, inner_rel,
+ sjinfo, restrictlist);
+
+ /*
+ * Add the joinrel to the query's joinrel list, and store it into the
+ * auxiliary hashtable if there is one. NB: GEQO requires us to append
+ * the new joinrel to the end of the list!
+ */
+ root->join_rel_list = lappend(root->join_rel_list, joinrel);
+
+ if (root->join_rel_hash)
{
- foreach(temp, rels)
+ JoinHashEntry *hentry;
+ bool found;
+
+ hentry = (JoinHashEntry *) hash_search(root->join_rel_hash,
+ &(joinrel->relids),
+ HASH_ENTER,
+ &found);
+ Assert(!found);
+ hentry->join_rel = joinrel;
+ }
+
+ /*
+ * Also, if dynamic-programming join search is active, add the new joinrel
+ * to the appropriate sublist. Note: you might think the Assert on number
+ * of members should be for equality, but some of the level 1 rels might
+ * have been joinrels already, so we can only assert <=.
+ */
+ if (root->join_rel_level)
+ {
+ Assert(root->join_cur_level > 0);
+ Assert(root->join_cur_level <= bms_num_members(joinrel->relids));
+ root->join_rel_level[root->join_cur_level] =
+ lappend(root->join_rel_level[root->join_cur_level], joinrel);
+ }
+
+ return joinrel;
+}
+
+/*
+ * build_joinrel_tlist
+ * Builds a join relation's target list from an input relation.
+ * (This is invoked twice to handle the two input relations.)
+ *
+ * The join's targetlist includes all Vars of its member relations that
+ * will still be needed above the join. This subroutine adds all such
+ * Vars from the specified input rel's tlist to the join rel's tlist.
+ *
+ * We also compute the expected width of the join's output, making use
+ * of data that was cached at the baserel level by set_rel_width().
+ */
+static void
+build_joinrel_tlist(PlannerInfo *root, RelOptInfo *joinrel,
+ RelOptInfo *input_rel)
+{
+ Relids relids = joinrel->relids;
+ ListCell *vars;
+
+ foreach(vars, input_rel->reltargetlist)
+ {
+ Node *origvar = (Node *) lfirst(vars);
+ Var *var;
+ RelOptInfo *baserel;
+ int ndx;
+
+ /*
+ * Ignore PlaceHolderVars in the input tlists; we'll make our own
+ * decisions about whether to copy them.
+ */
+ if (IsA(origvar, PlaceHolderVar))
+ continue;
+
+ /*
+ * We can't run into any child RowExprs here, but we could find a
+ * whole-row Var with a ConvertRowtypeExpr atop it.
+ */
+ var = (Var *) origvar;
+ while (!IsA(var, Var))
{
- temprelid = ((RelOptInfo *) lfirst(temp))->relids;
- if (same(temprelid, relid))
- return ((RelOptInfo *) (lfirst(temp)));
+ if (IsA(var, ConvertRowtypeExpr))
+ var = (Var *) ((ConvertRowtypeExpr *) var)->arg;
+ else
+ elog(ERROR, "unexpected node type in reltargetlist: %d",
+ (int) nodeTag(var));
+ }
+
+ /* Get the Var's original base rel */
+ baserel = find_base_rel(root, var->varno);
+
+ /* Is it still needed above this joinrel? */
+ ndx = var->varattno - baserel->min_attr;
+ if (bms_nonempty_difference(baserel->attr_needed[ndx], relids))
+ {
+ /* Yup, add it to the output */
+ joinrel->reltargetlist = lappend(joinrel->reltargetlist, origvar);
+ joinrel->width += baserel->attr_widths[ndx];
}
}
- return (NULL);
+}
+
+/*
+ * build_joinrel_restrictlist
+ * build_joinrel_joinlist
+ * These routines build lists of restriction and join clauses for a
+ * join relation from the joininfo lists of the relations it joins.
+ *
+ * These routines are separate because the restriction list must be
+ * built afresh for each pair of input sub-relations we consider, whereas
+ * the join list need only be computed once for any join RelOptInfo.
+ * The join list is fully determined by the set of rels making up the
+ * joinrel, so we should get the same results (up to ordering) from any
+ * candidate pair of sub-relations. But the restriction list is whatever
+ * is not handled in the sub-relations, so it depends on which
+ * sub-relations are considered.
+ *
+ * If a join clause from an input relation refers to base rels still not
+ * present in the joinrel, then it is still a join clause for the joinrel;
+ * we put it into the joininfo list for the joinrel. Otherwise,
+ * the clause is now a restrict clause for the joined relation, and we
+ * return it to the caller of build_joinrel_restrictlist() to be stored in
+ * join paths made from this pair of sub-relations. (It will not need to
+ * be considered further up the join tree.)
+ *
+ * In many case we will find the same RestrictInfos in both input
+ * relations' joinlists, so be careful to eliminate duplicates.
+ * Pointer equality should be a sufficient test for dups, since all
+ * the various joinlist entries ultimately refer to RestrictInfos
+ * pushed into them by distribute_restrictinfo_to_rels().
+ *
+ * 'joinrel' is a join relation node
+ * 'outer_rel' and 'inner_rel' are a pair of relations that can be joined
+ * to form joinrel.
+ *
+ * build_joinrel_restrictlist() returns a list of relevant restrictinfos,
+ * whereas build_joinrel_joinlist() stores its results in the joinrel's
+ * joininfo list. One or the other must accept each given clause!
+ *
+ * NB: Formerly, we made deep(!) copies of each input RestrictInfo to pass
+ * up to the join relation. I believe this is no longer necessary, because
+ * RestrictInfo nodes are no longer context-dependent. Instead, just include
+ * the original nodes in the lists made for the join relation.
+ */
+static List *
+build_joinrel_restrictlist(PlannerInfo *root,
+ RelOptInfo *joinrel,
+ RelOptInfo *outer_rel,
+ RelOptInfo *inner_rel)
+{
+ List *result;
+
+ /*
+ * Collect all the clauses that syntactically belong at this level,
+ * eliminating any duplicates (important since we will see many of the
+ * same clauses arriving from both input relations).
+ */
+ result = subbuild_joinrel_restrictlist(joinrel, outer_rel->joininfo, NIL);
+ result = subbuild_joinrel_restrictlist(joinrel, inner_rel->joininfo, result);
+
+ /*
+ * Add on any clauses derived from EquivalenceClasses. These cannot be
+ * redundant with the clauses in the joininfo lists, so don't bother
+ * checking.
+ */
+ result = list_concat(result,
+ generate_join_implied_equalities(root,
+ joinrel,
+ outer_rel,
+ inner_rel));
+
+ return result;
+}
+
+static void
+build_joinrel_joinlist(RelOptInfo *joinrel,
+ RelOptInfo *outer_rel,
+ RelOptInfo *inner_rel)
+{
+ List *result;
+
+ /*
+ * Collect all the clauses that syntactically belong above this level,
+ * eliminating any duplicates (important since we will see many of the
+ * same clauses arriving from both input relations).
+ */
+ result = subbuild_joinrel_joinlist(joinrel, outer_rel->joininfo, NIL);
+ result = subbuild_joinrel_joinlist(joinrel, inner_rel->joininfo, result);
+
+ joinrel->joininfo = result;
+}
+
+static List *
+subbuild_joinrel_restrictlist(RelOptInfo *joinrel,
+ List *joininfo_list,
+ List *new_restrictlist)
+{
+ ListCell *l;
+
+ foreach(l, joininfo_list)
+ {
+ RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
+
+ if (bms_is_subset(rinfo->required_relids, joinrel->relids))
+ {
+ /*
+ * This clause becomes a restriction clause for the joinrel, since
+ * it refers to no outside rels. Add it to the list, being
+ * careful to eliminate duplicates. (Since RestrictInfo nodes in
+ * different joinlists will have been multiply-linked rather than
+ * copied, pointer equality should be a sufficient test.)
+ */
+ new_restrictlist = list_append_unique_ptr(new_restrictlist, rinfo);
+ }
+ else
+ {
+ /*
+ * This clause is still a join clause at this level, so we ignore
+ * it in this routine.
+ */
+ }
+ }
+
+ return new_restrictlist;
+}
+
+static List *
+subbuild_joinrel_joinlist(RelOptInfo *joinrel,
+ List *joininfo_list,
+ List *new_joininfo)
+{
+ ListCell *l;
+
+ foreach(l, joininfo_list)
+ {
+ RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
+
+ if (bms_is_subset(rinfo->required_relids, joinrel->relids))
+ {
+ /*
+ * This clause becomes a restriction clause for the joinrel, since
+ * it refers to no outside rels. So we can ignore it in this
+ * routine.
+ */
+ }
+ else
+ {
+ /*
+ * This clause is still a join clause at this level, so add it to
+ * the new joininfo list, being careful to eliminate duplicates.
+ * (Since RestrictInfo nodes in different joinlists will have been
+ * multiply-linked rather than copied, pointer equality should be
+ * a sufficient test.)
+ */
+ new_joininfo = list_append_unique_ptr(new_joininfo, rinfo);
+ }
+ }
+
+ return new_joininfo;
}
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