* allpaths.c
* Routines to find possible search paths for processing a query
*
- * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.109 2003/11/29 19:51:50 pgsql Exp $
+ * src/backend/optimizer/path/allpaths.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
+#include <math.h>
+
+#include "catalog/pg_class.h"
+#include "nodes/nodeFuncs.h"
#ifdef OPTIMIZER_DEBUG
#include "nodes/print.h"
#endif
#include "optimizer/plancat.h"
#include "optimizer/planner.h"
#include "optimizer/prep.h"
+#include "optimizer/restrictinfo.h"
#include "optimizer/var.h"
-#include "parser/parsetree.h"
#include "parser/parse_clause.h"
+#include "parser/parsetree.h"
#include "rewrite/rewriteManip.h"
+#include "utils/lsyscache.h"
/* These parameters are set by GUC */
bool enable_geqo = false; /* just in case GUC doesn't set it */
int geqo_threshold;
+/* Hook for plugins to replace standard_join_search() */
+join_search_hook_type join_search_hook = NULL;
-static void set_base_rel_pathlists(Query *root);
-static void set_plain_rel_pathlist(Query *root, RelOptInfo *rel,
+
+static void set_base_rel_pathlists(PlannerInfo *root);
+static void set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
+ Index rti, RangeTblEntry *rte);
+static void set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
RangeTblEntry *rte);
-static void set_inherited_rel_pathlist(Query *root, RelOptInfo *rel,
- Index rti, RangeTblEntry *rte,
- List *inheritlist);
-static void set_subquery_pathlist(Query *root, RelOptInfo *rel,
+static void set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
+ Index rti, RangeTblEntry *rte);
+static List *accumulate_append_subpath(List *subpaths, Path *path);
+static void set_dummy_rel_pathlist(RelOptInfo *rel);
+static void set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
Index rti, RangeTblEntry *rte);
-static void set_function_pathlist(Query *root, RelOptInfo *rel,
+static void set_function_pathlist(PlannerInfo *root, RelOptInfo *rel,
RangeTblEntry *rte);
-static RelOptInfo *make_one_rel_by_joins(Query *root, int levels_needed,
- List *initial_rels);
+static void set_values_pathlist(PlannerInfo *root, RelOptInfo *rel,
+ RangeTblEntry *rte);
+static void set_cte_pathlist(PlannerInfo *root, RelOptInfo *rel,
+ RangeTblEntry *rte);
+static void set_worktable_pathlist(PlannerInfo *root, RelOptInfo *rel,
+ RangeTblEntry *rte);
+static void set_foreign_pathlist(PlannerInfo *root, RelOptInfo *rel,
+ RangeTblEntry *rte);
+static RelOptInfo *make_rel_from_joinlist(PlannerInfo *root, List *joinlist);
static bool subquery_is_pushdown_safe(Query *subquery, Query *topquery,
bool *differentTypes);
static bool recurse_pushdown_safe(Node *setOp, Query *topquery,
bool *differentTypes);
static bool qual_is_pushdown_safe(Query *subquery, Index rti, Node *qual,
bool *differentTypes);
-static void subquery_push_qual(Query *subquery, Index rti, Node *qual);
+static void subquery_push_qual(Query *subquery,
+ RangeTblEntry *rte, Index rti, Node *qual);
static void recurse_push_qual(Node *setOp, Query *topquery,
- Index rti, Node *qual);
+ RangeTblEntry *rte, Index rti, Node *qual);
/*
* single rel that represents the join of all base rels in the query.
*/
RelOptInfo *
-make_one_rel(Query *root)
+make_one_rel(PlannerInfo *root, List *joinlist)
{
RelOptInfo *rel;
/*
* Generate access paths for the entire join tree.
*/
- Assert(root->jointree != NULL && IsA(root->jointree, FromExpr));
-
- rel = make_fromexpr_rel(root, root->jointree);
+ rel = make_rel_from_joinlist(root, joinlist);
/*
- * The result should join all the query's base rels.
+ * The result should join all and only the query's base rels.
*/
- Assert(bms_num_members(rel->relids) == length(root->base_rel_list));
+#ifdef USE_ASSERT_CHECKING
+ {
+ int num_base_rels = 0;
+ Index rti;
+
+ for (rti = 1; rti < root->simple_rel_array_size; rti++)
+ {
+ RelOptInfo *brel = root->simple_rel_array[rti];
+
+ if (brel == NULL)
+ continue;
+
+ Assert(brel->relid == rti); /* sanity check on array */
+
+ /* ignore RTEs that are "other rels" */
+ if (brel->reloptkind != RELOPT_BASEREL)
+ continue;
+
+ Assert(bms_is_member(rti, rel->relids));
+ num_base_rels++;
+ }
+
+ Assert(bms_num_members(rel->relids) == num_base_rels);
+ }
+#endif
return rel;
}
* Each useful path is attached to its relation's 'pathlist' field.
*/
static void
-set_base_rel_pathlists(Query *root)
+set_base_rel_pathlists(PlannerInfo *root)
{
- List *rellist;
+ Index rti;
- foreach(rellist, root->base_rel_list)
+ for (rti = 1; rti < root->simple_rel_array_size; rti++)
{
- RelOptInfo *rel = (RelOptInfo *) lfirst(rellist);
- Index rti = rel->relid;
- RangeTblEntry *rte;
- List *inheritlist;
+ RelOptInfo *rel = root->simple_rel_array[rti];
- Assert(rti > 0); /* better be base rel */
- rte = rt_fetch(rti, root->rtable);
+ /* there may be empty slots corresponding to non-baserel RTEs */
+ if (rel == NULL)
+ continue;
- if (rel->rtekind == RTE_SUBQUERY)
- {
- /* Subquery --- generate a separate plan for it */
- set_subquery_pathlist(root, rel, rti, rte);
- }
- else if (rel->rtekind == RTE_FUNCTION)
- {
- /* RangeFunction --- generate a separate plan for it */
- set_function_pathlist(root, rel, rte);
- }
- else if ((inheritlist = expand_inherited_rtentry(root, rti, true))
- != NIL)
+ Assert(rel->relid == rti); /* sanity check on array */
+
+ /* ignore RTEs that are "other rels" */
+ if (rel->reloptkind != RELOPT_BASEREL)
+ continue;
+
+ set_rel_pathlist(root, rel, rti, root->simple_rte_array[rti]);
+ }
+}
+
+/*
+ * set_rel_pathlist
+ * Build access paths for a base relation
+ */
+static void
+set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
+ Index rti, RangeTblEntry *rte)
+{
+ if (rte->inh)
+ {
+ /* It's an "append relation", process accordingly */
+ set_append_rel_pathlist(root, rel, rti, rte);
+ }
+ else if (rel->rtekind == RTE_SUBQUERY)
+ {
+ /* Subquery --- generate a separate plan for it */
+ set_subquery_pathlist(root, rel, rti, rte);
+ }
+ else if (rel->rtekind == RTE_FUNCTION)
+ {
+ /* RangeFunction --- generate a suitable path for it */
+ set_function_pathlist(root, rel, rte);
+ }
+ else if (rel->rtekind == RTE_VALUES)
+ {
+ /* Values list --- generate a suitable path for it */
+ set_values_pathlist(root, rel, rte);
+ }
+ else if (rel->rtekind == RTE_CTE)
+ {
+ /* CTE reference --- generate a suitable path for it */
+ if (rte->self_reference)
+ set_worktable_pathlist(root, rel, rte);
+ else
+ set_cte_pathlist(root, rel, rte);
+ }
+ else
+ {
+ Assert(rel->rtekind == RTE_RELATION);
+ if (get_rel_relkind(rte->relid) == RELKIND_FOREIGN_TABLE)
{
- /* Relation is root of an inheritance tree, process specially */
- set_inherited_rel_pathlist(root, rel, rti, rte, inheritlist);
+ /* Foreign table */
+ set_foreign_pathlist(root, rel, rte);
}
else
{
/* Plain relation */
set_plain_rel_pathlist(root, rel, rte);
}
+ }
#ifdef OPTIMIZER_DEBUG
- debug_print_rel(root, rel);
+ debug_print_rel(root, rel);
#endif
- }
}
/*
* Build access paths for a plain relation (no subquery, no inheritance)
*/
static void
-set_plain_rel_pathlist(Query *root, RelOptInfo *rel, RangeTblEntry *rte)
+set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
{
+ /*
+ * If we can prove we don't need to scan the rel via constraint exclusion,
+ * set up a single dummy path for it. We only need to check for regular
+ * baserels; if it's an otherrel, CE was already checked in
+ * set_append_rel_pathlist().
+ */
+ if (rel->reloptkind == RELOPT_BASEREL &&
+ relation_excluded_by_constraints(root, rel, rte))
+ {
+ set_dummy_rel_pathlist(rel);
+ return;
+ }
+
+ /*
+ * Test any partial indexes of rel for applicability. We must do this
+ * first since partial unique indexes can affect size estimates.
+ */
+ check_partial_indexes(root, rel);
+
/* Mark rel with estimated output rows, width, etc */
set_baserel_size_estimates(root, rel);
+ /*
+ * Check to see if we can extract any restriction conditions from join
+ * quals that are OR-of-AND structures. If so, add them to the rel's
+ * restriction list, and redo the above steps.
+ */
+ if (create_or_index_quals(root, rel))
+ {
+ check_partial_indexes(root, rel);
+ set_baserel_size_estimates(root, rel);
+ }
+
/*
* Generate paths and add them to the rel's pathlist.
*
/* Consider sequential scan */
add_path(rel, create_seqscan_path(root, rel));
- /* Consider TID scans */
- create_tidscan_paths(root, rel);
-
- /* Consider index paths for both simple and OR index clauses */
+ /* Consider index scans */
create_index_paths(root, rel);
- /* create_index_paths must be done before create_or_index_paths */
- create_or_index_paths(root, rel);
+ /* Consider TID scans */
+ create_tidscan_paths(root, rel);
/* Now find the cheapest of the paths for this rel */
set_cheapest(rel);
}
/*
- * set_inherited_rel_pathlist
- * Build access paths for a inheritance tree rooted at rel
- *
- * inheritlist is a list of RT indexes of all tables in the inheritance tree,
- * including a duplicate of the parent itself. Note we will not come here
- * unless there's at least one child in addition to the parent.
+ * set_append_rel_pathlist
+ * Build access paths for an "append relation"
*
- * NOTE: the passed-in rel and RTE will henceforth represent the appended
- * result of the whole inheritance tree. The members of inheritlist represent
- * the individual tables --- in particular, the inheritlist member that is a
- * duplicate of the parent RTE represents the parent table alone.
- * We will generate plans to scan the individual tables that refer to
- * the inheritlist RTEs, whereas Vars elsewhere in the plan tree that
- * refer to the original RTE are taken to refer to the append output.
- * In particular, this means we have separate RelOptInfos for the parent
- * table and for the append output, which is a good thing because they're
- * not the same size.
+ * The passed-in rel and RTE represent the entire append relation. The
+ * relation's contents are computed by appending together the output of
+ * the individual member relations. Note that in the inheritance case,
+ * the first member relation is actually the same table as is mentioned in
+ * the parent RTE ... but it has a different RTE and RelOptInfo. This is
+ * a good thing because their outputs are not the same size.
*/
static void
-set_inherited_rel_pathlist(Query *root, RelOptInfo *rel,
- Index rti, RangeTblEntry *rte,
- List *inheritlist)
+set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
+ Index rti, RangeTblEntry *rte)
{
int parentRTindex = rti;
- Oid parentOID = rte->relid;
+ List *live_childrels = NIL;
List *subpaths = NIL;
- List *il;
-
- /*
- * XXX for now, can't handle inherited expansion of FOR UPDATE; can we
- * do better?
- */
- if (intMember(parentRTindex, root->rowMarks))
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("SELECT FOR UPDATE is not supported for inheritance queries")));
+ List *all_child_pathkeys = NIL;
+ double parent_rows;
+ double parent_size;
+ double *parent_attrsizes;
+ int nattrs;
+ ListCell *l;
/*
- * The executor will check the parent table's access permissions when
- * it examines the parent's inheritlist entry. There's no need to
- * check twice, so turn off access check bits in the original RTE.
+ * Initialize to compute size estimates for whole append relation.
+ *
+ * We handle width estimates by weighting the widths of different child
+ * rels proportionally to their number of rows. This is sensible because
+ * the use of width estimates is mainly to compute the total relation
+ * "footprint" if we have to sort or hash it. To do this, we sum the
+ * total equivalent size (in "double" arithmetic) and then divide by the
+ * total rowcount estimate. This is done separately for the total rel
+ * width and each attribute.
+ *
+ * Note: if you consider changing this logic, beware that child rels could
+ * have zero rows and/or width, if they were excluded by constraints.
*/
- rte->checkForRead = false;
- rte->checkForWrite = false;
+ parent_rows = 0;
+ parent_size = 0;
+ nattrs = rel->max_attr - rel->min_attr + 1;
+ parent_attrsizes = (double *) palloc0(nattrs * sizeof(double));
/*
- * Initialize to compute size estimates for whole inheritance tree
+ * Generate access paths for each member relation, and pick the cheapest
+ * path for each one.
*/
- rel->rows = 0;
- rel->width = 0;
-
- /*
- * Generate access paths for each table in the tree (parent AND
- * children), and pick the cheapest path for each table.
- */
- foreach(il, inheritlist)
+ foreach(l, root->append_rel_list)
{
- int childRTindex = lfirsti(il);
- RangeTblEntry *childrte;
- Oid childOID;
+ AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
+ int childRTindex;
+ RangeTblEntry *childRTE;
RelOptInfo *childrel;
- List *reltlist;
- List *parentvars;
- List *childvars;
+ List *childquals;
+ Node *childqual;
+ ListCell *lcp;
+ ListCell *parentvars;
+ ListCell *childvars;
+
+ /* append_rel_list contains all append rels; ignore others */
+ if (appinfo->parent_relid != parentRTindex)
+ continue;
- childrte = rt_fetch(childRTindex, root->rtable);
- childOID = childrte->relid;
+ childRTindex = appinfo->child_relid;
+ childRTE = root->simple_rte_array[childRTindex];
/*
- * Make a RelOptInfo for the child so we can do planning. Do NOT
- * attach the RelOptInfo to the query's base_rel_list, however,
- * since the child is not part of the main join tree. Instead,
- * the child RelOptInfo is added to other_rel_list.
+ * The child rel's RelOptInfo was already created during
+ * add_base_rels_to_query.
*/
- childrel = build_other_rel(root, childRTindex);
+ childrel = find_base_rel(root, childRTindex);
+ Assert(childrel->reloptkind == RELOPT_OTHER_MEMBER_REL);
/*
- * Copy the parent's targetlist and restriction quals to the
- * child, with attribute-number adjustment as needed. We don't
- * bother to copy the join quals, since we can't do any joining of
- * the individual tables. Also, we just zap attr_needed rather
- * than trying to adjust it; it won't be looked at in the child.
+ * We have to copy the parent's targetlist and quals to the child,
+ * with appropriate substitution of variables. However, only the
+ * baserestrictinfo quals are needed before we can check for
+ * constraint exclusion; so do that first and then check to see if we
+ * can disregard this child.
+ *
+ * As of 8.4, the child rel's targetlist might contain non-Var
+ * expressions, which means that substitution into the quals could
+ * produce opportunities for const-simplification, and perhaps even
+ * pseudoconstant quals. To deal with this, we strip the RestrictInfo
+ * nodes, do the substitution, do const-simplification, and then
+ * reconstitute the RestrictInfo layer.
*/
- reltlist = FastListValue(&rel->reltargetlist);
- reltlist = (List *)
- adjust_inherited_attrs((Node *) reltlist,
- parentRTindex,
- parentOID,
- childRTindex,
- childOID);
- FastListFromList(&childrel->reltargetlist, reltlist);
- childrel->attr_needed = NULL;
- childrel->baserestrictinfo = (List *)
- adjust_inherited_attrs((Node *) rel->baserestrictinfo,
- parentRTindex,
- parentOID,
- childRTindex,
- childOID);
+ childquals = get_all_actual_clauses(rel->baserestrictinfo);
+ childquals = (List *) adjust_appendrel_attrs((Node *) childquals,
+ appinfo);
+ childqual = eval_const_expressions(root, (Node *)
+ make_ands_explicit(childquals));
+ if (childqual && IsA(childqual, Const) &&
+ (((Const *) childqual)->constisnull ||
+ !DatumGetBool(((Const *) childqual)->constvalue)))
+ {
+ /*
+ * Restriction reduces to constant FALSE or constant NULL after
+ * substitution, so this child need not be scanned.
+ */
+ set_dummy_rel_pathlist(childrel);
+ continue;
+ }
+ childquals = make_ands_implicit((Expr *) childqual);
+ childquals = make_restrictinfos_from_actual_clauses(root,
+ childquals);
+ childrel->baserestrictinfo = childquals;
+
+ if (relation_excluded_by_constraints(root, childrel, childRTE))
+ {
+ /*
+ * This child need not be scanned, so we can omit it from the
+ * appendrel. Mark it with a dummy cheapest-path though, in case
+ * best_appendrel_indexscan() looks at it later.
+ */
+ set_dummy_rel_pathlist(childrel);
+ continue;
+ }
+
+ /* CE failed, so finish copying targetlist and join quals */
+ childrel->joininfo = (List *)
+ adjust_appendrel_attrs((Node *) rel->joininfo,
+ appinfo);
+ childrel->reltargetlist = (List *)
+ adjust_appendrel_attrs((Node *) rel->reltargetlist,
+ appinfo);
+
+ /*
+ * We have to make child entries in the EquivalenceClass data
+ * structures as well. This is needed either if the parent
+ * participates in some eclass joins (because we will want to
+ * consider inner-indexscan joins on the individual children)
+ * or if the parent has useful pathkeys (because we should try
+ * to build MergeAppend paths that produce those sort orderings).
+ */
+ if (rel->has_eclass_joins || has_useful_pathkeys(root, rel))
+ add_child_rel_equivalences(root, appinfo, rel, childrel);
+ childrel->has_eclass_joins = rel->has_eclass_joins;
/*
- * Now compute child access paths, and save the cheapest.
+ * Note: we could compute appropriate attr_needed data for the child's
+ * variables, by transforming the parent's attr_needed through the
+ * translated_vars mapping. However, currently there's no need
+ * because attr_needed is only examined for base relations not
+ * otherrels. So we just leave the child's attr_needed empty.
*/
- set_plain_rel_pathlist(root, childrel, childrte);
- subpaths = lappend(subpaths, childrel->cheapest_total_path);
+ /* Remember which childrels are live, for MergeAppend logic below */
+ live_childrels = lappend(live_childrels, childrel);
/*
- * Propagate size information from the child back to the parent.
- * For simplicity, we use the largest widths from any child as the
- * parent estimates.
+ * Compute the child's access paths, and add the cheapest one to the
+ * Append path we are constructing for the parent.
*/
- rel->rows += childrel->rows;
- if (childrel->width > rel->width)
- rel->width = childrel->width;
+ set_rel_pathlist(root, childrel, childRTindex, childRTE);
- childvars = FastListValue(&childrel->reltargetlist);
- foreach(parentvars, FastListValue(&rel->reltargetlist))
+ subpaths = accumulate_append_subpath(subpaths,
+ childrel->cheapest_total_path);
+
+ /*
+ * Collect a list of all the available path orderings for all the
+ * children. We use this as a heuristic to indicate which sort
+ * orderings we should build MergeAppend paths for.
+ */
+ foreach(lcp, childrel->pathlist)
{
- Var *parentvar = (Var *) lfirst(parentvars);
- Var *childvar = (Var *) lfirst(childvars);
- int parentndx = parentvar->varattno - rel->min_attr;
- int childndx = childvar->varattno - childrel->min_attr;
-
- if (childrel->attr_widths[childndx] > rel->attr_widths[parentndx])
- rel->attr_widths[parentndx] = childrel->attr_widths[childndx];
- childvars = lnext(childvars);
+ Path *childpath = (Path *) lfirst(lcp);
+ List *childkeys = childpath->pathkeys;
+ ListCell *lpk;
+ bool found = false;
+
+ /* Ignore unsorted paths */
+ if (childkeys == NIL)
+ continue;
+
+ /* Have we already seen this ordering? */
+ foreach(lpk, all_child_pathkeys)
+ {
+ List *existing_pathkeys = (List *) lfirst(lpk);
+
+ if (compare_pathkeys(existing_pathkeys,
+ childkeys) == PATHKEYS_EQUAL)
+ {
+ found = true;
+ break;
+ }
+ }
+ if (!found)
+ {
+ /* No, so add it to all_child_pathkeys */
+ all_child_pathkeys = lappend(all_child_pathkeys, childkeys);
+ }
+ }
+
+ /*
+ * Accumulate size information from each child.
+ */
+ if (childrel->rows > 0)
+ {
+ parent_rows += childrel->rows;
+ parent_size += childrel->width * childrel->rows;
+
+ forboth(parentvars, rel->reltargetlist,
+ childvars, childrel->reltargetlist)
+ {
+ Var *parentvar = (Var *) lfirst(parentvars);
+ Var *childvar = (Var *) lfirst(childvars);
+
+ /*
+ * Accumulate per-column estimates too. Whole-row Vars and
+ * PlaceHolderVars can be ignored here.
+ */
+ if (IsA(parentvar, Var) &&
+ IsA(childvar, Var))
+ {
+ int pndx = parentvar->varattno - rel->min_attr;
+ int cndx = childvar->varattno - childrel->min_attr;
+
+ parent_attrsizes[pndx] += childrel->attr_widths[cndx] * childrel->rows;
+ }
+ }
}
}
/*
- * Finally, build Append path and install it as the only access path
- * for the parent rel.
+ * Save the finished size estimates.
+ */
+ rel->rows = parent_rows;
+ if (parent_rows > 0)
+ {
+ int i;
+
+ rel->width = rint(parent_size / parent_rows);
+ for (i = 0; i < nattrs; i++)
+ rel->attr_widths[i] = rint(parent_attrsizes[i] / parent_rows);
+ }
+ else
+ rel->width = 0; /* attr_widths should be zero already */
+
+ /*
+ * Set "raw tuples" count equal to "rows" for the appendrel; needed
+ * because some places assume rel->tuples is valid for any baserel.
+ */
+ rel->tuples = parent_rows;
+
+ pfree(parent_attrsizes);
+
+ /*
+ * Next, build an unordered Append path for the rel. (Note: this is
+ * correct even if we have zero or one live subpath due to constraint
+ * exclusion.)
*/
add_path(rel, (Path *) create_append_path(rel, subpaths));
+ /*
+ * Next, build MergeAppend paths based on the collected list of child
+ * pathkeys. We consider both cheapest-startup and cheapest-total
+ * cases, ie, for each interesting ordering, collect all the cheapest
+ * startup subpaths and all the cheapest total paths, and build a
+ * MergeAppend path for each list.
+ */
+ foreach(l, all_child_pathkeys)
+ {
+ List *pathkeys = (List *) lfirst(l);
+ List *startup_subpaths = NIL;
+ List *total_subpaths = NIL;
+ bool startup_neq_total = false;
+ ListCell *lcr;
+
+ /* Select the child paths for this ordering... */
+ foreach(lcr, live_childrels)
+ {
+ RelOptInfo *childrel = (RelOptInfo *) lfirst(lcr);
+ Path *cheapest_startup,
+ *cheapest_total;
+
+ /* Locate the right paths, if they are available. */
+ cheapest_startup =
+ get_cheapest_path_for_pathkeys(childrel->pathlist,
+ pathkeys,
+ STARTUP_COST);
+ cheapest_total =
+ get_cheapest_path_for_pathkeys(childrel->pathlist,
+ pathkeys,
+ TOTAL_COST);
+
+ /*
+ * If we can't find any paths with the right order just add the
+ * cheapest-total path; we'll have to sort it.
+ */
+ if (cheapest_startup == NULL)
+ cheapest_startup = childrel->cheapest_total_path;
+ if (cheapest_total == NULL)
+ cheapest_total = childrel->cheapest_total_path;
+
+ /*
+ * Notice whether we actually have different paths for the
+ * "cheapest" and "total" cases; frequently there will be no
+ * point in two create_merge_append_path() calls.
+ */
+ if (cheapest_startup != cheapest_total)
+ startup_neq_total = true;
+
+ startup_subpaths =
+ accumulate_append_subpath(startup_subpaths, cheapest_startup);
+ total_subpaths =
+ accumulate_append_subpath(total_subpaths, cheapest_total);
+ }
+
+ /* ... and build the MergeAppend paths */
+ add_path(rel, (Path *) create_merge_append_path(root,
+ rel,
+ startup_subpaths,
+ pathkeys));
+ if (startup_neq_total)
+ add_path(rel, (Path *) create_merge_append_path(root,
+ rel,
+ total_subpaths,
+ pathkeys));
+ }
+
+ /* Select cheapest path */
+ set_cheapest(rel);
+}
+
+/*
+ * accumulate_append_subpath
+ * Add a subpath to the list being built for an Append or MergeAppend
+ *
+ * It's possible that the child is itself an Append path, in which case
+ * we can "cut out the middleman" and just add its child paths to our
+ * own list. (We don't try to do this earlier because we need to
+ * apply both levels of transformation to the quals.)
+ */
+static List *
+accumulate_append_subpath(List *subpaths, Path *path)
+{
+ if (IsA(path, AppendPath))
+ {
+ AppendPath *apath = (AppendPath *) path;
+
+ /* list_copy is important here to avoid sharing list substructure */
+ return list_concat(subpaths, list_copy(apath->subpaths));
+ }
+ else
+ return lappend(subpaths, path);
+}
+
+/*
+ * set_dummy_rel_pathlist
+ * Build a dummy path for a relation that's been excluded by constraints
+ *
+ * Rather than inventing a special "dummy" path type, we represent this as an
+ * AppendPath with no members (see also IS_DUMMY_PATH macro).
+ */
+static void
+set_dummy_rel_pathlist(RelOptInfo *rel)
+{
+ /* Set dummy size estimates --- we leave attr_widths[] as zeroes */
+ rel->rows = 0;
+ rel->width = 0;
+
+ add_path(rel, (Path *) create_append_path(rel, NIL));
+
/* Select cheapest path (pretty easy in this case...) */
set_cheapest(rel);
}
+/* quick-and-dirty test to see if any joining is needed */
+static bool
+has_multiple_baserels(PlannerInfo *root)
+{
+ int num_base_rels = 0;
+ Index rti;
+
+ for (rti = 1; rti < root->simple_rel_array_size; rti++)
+ {
+ RelOptInfo *brel = root->simple_rel_array[rti];
+
+ if (brel == NULL)
+ continue;
+
+ /* ignore RTEs that are "other rels" */
+ if (brel->reloptkind == RELOPT_BASEREL)
+ if (++num_base_rels > 1)
+ return true;
+ }
+ return false;
+}
+
/*
* set_subquery_pathlist
* Build the (single) access path for a subquery RTE
*/
static void
-set_subquery_pathlist(Query *root, RelOptInfo *rel,
+set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
Index rti, RangeTblEntry *rte)
{
+ Query *parse = root->parse;
Query *subquery = rte->subquery;
bool *differentTypes;
+ double tuple_fraction;
+ PlannerInfo *subroot;
List *pathkeys;
+ /*
+ * Must copy the Query so that planning doesn't mess up the RTE contents
+ * (really really need to fix the planner to not scribble on its input,
+ * someday).
+ */
+ subquery = copyObject(subquery);
+
/* We need a workspace for keeping track of set-op type coercions */
differentTypes = (bool *)
- palloc0((length(subquery->targetList) + 1) * sizeof(bool));
+ palloc0((list_length(subquery->targetList) + 1) * sizeof(bool));
/*
* If there are any restriction clauses that have been attached to the
- * subquery relation, consider pushing them down to become HAVING
- * quals of the subquery itself. (Not WHERE clauses, since they may
- * refer to subquery outputs that are aggregate results. But
- * planner.c will transfer them into the subquery's WHERE if they do
- * not.) This transformation is useful because it may allow us to
- * generate a better plan for the subquery than evaluating all the
- * subquery output rows and then filtering them.
+ * subquery relation, consider pushing them down to become WHERE or HAVING
+ * quals of the subquery itself. This transformation is useful because it
+ * may allow us to generate a better plan for the subquery than evaluating
+ * all the subquery output rows and then filtering them.
*
- * There are several cases where we cannot push down clauses.
- * Restrictions involving the subquery are checked by
- * subquery_is_pushdown_safe(). Restrictions on individual clauses
- * are checked by qual_is_pushdown_safe().
+ * There are several cases where we cannot push down clauses. Restrictions
+ * involving the subquery are checked by subquery_is_pushdown_safe().
+ * Restrictions on individual clauses are checked by
+ * qual_is_pushdown_safe(). Also, we don't want to push down
+ * pseudoconstant clauses; better to have the gating node above the
+ * subquery.
*
* Non-pushed-down clauses will get evaluated as qpquals of the
* SubqueryScan node.
{
/* OK to consider pushing down individual quals */
List *upperrestrictlist = NIL;
- List *lst;
+ ListCell *l;
- foreach(lst, rel->baserestrictinfo)
+ foreach(l, rel->baserestrictinfo)
{
- RestrictInfo *rinfo = (RestrictInfo *) lfirst(lst);
+ RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
Node *clause = (Node *) rinfo->clause;
- if (qual_is_pushdown_safe(subquery, rti, clause, differentTypes))
+ if (!rinfo->pseudoconstant &&
+ qual_is_pushdown_safe(subquery, rti, clause, differentTypes))
{
/* Push it down */
- subquery_push_qual(subquery, rti, clause);
+ subquery_push_qual(subquery, rte, rti, clause);
}
else
{
pfree(differentTypes);
- /* Generate the plan for the subquery */
- rel->subplan = subquery_planner(subquery, 0.0 /* default case */ );
+ /*
+ * We can safely pass the outer tuple_fraction down to the subquery if the
+ * outer level has no joining, aggregation, or sorting to do. Otherwise
+ * we'd better tell the subquery to plan for full retrieval. (XXX This
+ * could probably be made more intelligent ...)
+ */
+ if (parse->hasAggs ||
+ parse->groupClause ||
+ parse->havingQual ||
+ parse->distinctClause ||
+ parse->sortClause ||
+ has_multiple_baserels(root))
+ tuple_fraction = 0.0; /* default case */
+ else
+ tuple_fraction = root->tuple_fraction;
- /* Copy number of output rows from subplan */
- rel->tuples = rel->subplan->plan_rows;
+ /* Generate the plan for the subquery */
+ rel->subplan = subquery_planner(root->glob, subquery,
+ root,
+ false, tuple_fraction,
+ &subroot);
+ rel->subrtable = subroot->parse->rtable;
+ rel->subrowmark = subroot->rowMarks;
/* Mark rel with estimated output rows, width, etc */
- set_baserel_size_estimates(root, rel);
+ set_subquery_size_estimates(root, rel, subroot);
/* Convert subquery pathkeys to outer representation */
- pathkeys = build_subquery_pathkeys(root, rel, subquery);
+ pathkeys = convert_subquery_pathkeys(root, rel, subroot->query_pathkeys);
/* Generate appropriate path */
add_path(rel, create_subqueryscan_path(rel, pathkeys));
* Build the (single) access path for a function RTE
*/
static void
-set_function_pathlist(Query *root, RelOptInfo *rel, RangeTblEntry *rte)
+set_function_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
{
/* Mark rel with estimated output rows, width, etc */
set_function_size_estimates(root, rel);
}
/*
- * make_fromexpr_rel
- * Build access paths for a FromExpr jointree node.
+ * set_values_pathlist
+ * Build the (single) access path for a VALUES RTE
*/
-RelOptInfo *
-make_fromexpr_rel(Query *root, FromExpr *from)
+static void
+set_values_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
+{
+ /* Mark rel with estimated output rows, width, etc */
+ set_values_size_estimates(root, rel);
+
+ /* Generate appropriate path */
+ add_path(rel, create_valuesscan_path(root, rel));
+
+ /* Select cheapest path (pretty easy in this case...) */
+ set_cheapest(rel);
+}
+
+/*
+ * set_cte_pathlist
+ * Build the (single) access path for a non-self-reference CTE RTE
+ */
+static void
+set_cte_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
+{
+ Plan *cteplan;
+ PlannerInfo *cteroot;
+ Index levelsup;
+ int ndx;
+ ListCell *lc;
+ int plan_id;
+
+ /*
+ * Find the referenced CTE, and locate the plan previously made for it.
+ */
+ levelsup = rte->ctelevelsup;
+ cteroot = root;
+ while (levelsup-- > 0)
+ {
+ cteroot = cteroot->parent_root;
+ if (!cteroot) /* shouldn't happen */
+ elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
+ }
+
+ /*
+ * Note: cte_plan_ids can be shorter than cteList, if we are still working
+ * on planning the CTEs (ie, this is a side-reference from another CTE).
+ * So we mustn't use forboth here.
+ */
+ ndx = 0;
+ foreach(lc, cteroot->parse->cteList)
+ {
+ CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
+
+ if (strcmp(cte->ctename, rte->ctename) == 0)
+ break;
+ ndx++;
+ }
+ if (lc == NULL) /* shouldn't happen */
+ elog(ERROR, "could not find CTE \"%s\"", rte->ctename);
+ if (ndx >= list_length(cteroot->cte_plan_ids))
+ elog(ERROR, "could not find plan for CTE \"%s\"", rte->ctename);
+ plan_id = list_nth_int(cteroot->cte_plan_ids, ndx);
+ Assert(plan_id > 0);
+ cteplan = (Plan *) list_nth(root->glob->subplans, plan_id - 1);
+
+ /* Mark rel with estimated output rows, width, etc */
+ set_cte_size_estimates(root, rel, cteplan);
+
+ /* Generate appropriate path */
+ add_path(rel, create_ctescan_path(root, rel));
+
+ /* Select cheapest path (pretty easy in this case...) */
+ set_cheapest(rel);
+}
+
+/*
+ * set_worktable_pathlist
+ * Build the (single) access path for a self-reference CTE RTE
+ */
+static void
+set_worktable_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
+{
+ Plan *cteplan;
+ PlannerInfo *cteroot;
+ Index levelsup;
+
+ /*
+ * We need to find the non-recursive term's plan, which is in the plan
+ * level that's processing the recursive UNION, which is one level *below*
+ * where the CTE comes from.
+ */
+ levelsup = rte->ctelevelsup;
+ if (levelsup == 0) /* shouldn't happen */
+ elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
+ levelsup--;
+ cteroot = root;
+ while (levelsup-- > 0)
+ {
+ cteroot = cteroot->parent_root;
+ if (!cteroot) /* shouldn't happen */
+ elog(ERROR, "bad levelsup for CTE \"%s\"", rte->ctename);
+ }
+ cteplan = cteroot->non_recursive_plan;
+ if (!cteplan) /* shouldn't happen */
+ elog(ERROR, "could not find plan for CTE \"%s\"", rte->ctename);
+
+ /* Mark rel with estimated output rows, width, etc */
+ set_cte_size_estimates(root, rel, cteplan);
+
+ /* Generate appropriate path */
+ add_path(rel, create_worktablescan_path(root, rel));
+
+ /* Select cheapest path (pretty easy in this case...) */
+ set_cheapest(rel);
+}
+
+/*
+ * set_foreign_pathlist
+ * Build the (single) access path for a foreign table RTE
+ */
+static void
+set_foreign_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
+{
+ /* Mark rel with estimated output rows, width, etc */
+ set_foreign_size_estimates(root, rel);
+
+ /* Generate appropriate path */
+ add_path(rel, (Path *) create_foreignscan_path(root, rel));
+
+ /* Select cheapest path (pretty easy in this case...) */
+ set_cheapest(rel);
+}
+
+/*
+ * make_rel_from_joinlist
+ * Build access paths using a "joinlist" to guide the join path search.
+ *
+ * See comments for deconstruct_jointree() for definition of the joinlist
+ * data structure.
+ */
+static RelOptInfo *
+make_rel_from_joinlist(PlannerInfo *root, List *joinlist)
{
int levels_needed;
- List *initial_rels = NIL;
- List *jt;
+ List *initial_rels;
+ ListCell *jl;
/*
- * Count the number of child jointree nodes. This is the depth of the
- * dynamic-programming algorithm we must employ to consider all ways
- * of joining the child nodes.
+ * Count the number of child joinlist nodes. This is the depth of the
+ * dynamic-programming algorithm we must employ to consider all ways of
+ * joining the child nodes.
*/
- levels_needed = length(from->fromlist);
+ levels_needed = list_length(joinlist);
if (levels_needed <= 0)
return NULL; /* nothing to do? */
/*
- * Construct a list of rels corresponding to the child jointree nodes.
+ * Construct a list of rels corresponding to the child joinlist nodes.
* This may contain both base rels and rels constructed according to
- * explicit JOIN directives.
+ * sub-joinlists.
*/
- foreach(jt, from->fromlist)
+ initial_rels = NIL;
+ foreach(jl, joinlist)
{
- Node *jtnode = (Node *) lfirst(jt);
+ Node *jlnode = (Node *) lfirst(jl);
+ RelOptInfo *thisrel;
- initial_rels = lappend(initial_rels,
- make_jointree_rel(root, jtnode));
+ if (IsA(jlnode, RangeTblRef))
+ {
+ int varno = ((RangeTblRef *) jlnode)->rtindex;
+
+ thisrel = find_base_rel(root, varno);
+ }
+ else if (IsA(jlnode, List))
+ {
+ /* Recurse to handle subproblem */
+ thisrel = make_rel_from_joinlist(root, (List *) jlnode);
+ }
+ else
+ {
+ elog(ERROR, "unrecognized joinlist node type: %d",
+ (int) nodeTag(jlnode));
+ thisrel = NULL; /* keep compiler quiet */
+ }
+
+ initial_rels = lappend(initial_rels, thisrel);
}
if (levels_needed == 1)
{
/*
- * Single jointree node, so we're done.
+ * Single joinlist node, so we're done.
*/
- return (RelOptInfo *) lfirst(initial_rels);
+ return (RelOptInfo *) linitial(initial_rels);
}
else
{
/*
* Consider the different orders in which we could join the rels,
- * using either GEQO or regular optimizer.
+ * using a plugin, GEQO, or the regular join search code.
+ *
+ * We put the initial_rels list into a PlannerInfo field because
+ * has_legal_joinclause() needs to look at it (ugly :-().
*/
- if (enable_geqo && levels_needed >= geqo_threshold)
+ root->initial_rels = initial_rels;
+
+ if (join_search_hook)
+ return (*join_search_hook) (root, levels_needed, initial_rels);
+ else if (enable_geqo && levels_needed >= geqo_threshold)
return geqo(root, levels_needed, initial_rels);
else
- return make_one_rel_by_joins(root, levels_needed, initial_rels);
+ return standard_join_search(root, levels_needed, initial_rels);
}
}
/*
- * make_one_rel_by_joins
- * Find all possible joinpaths for a query by successively finding ways
+ * standard_join_search
+ * Find possible joinpaths for a query by successively finding ways
* to join component relations into join relations.
*
* 'levels_needed' is the number of iterations needed, ie, the number of
*
* 'initial_rels' is a list of RelOptInfo nodes for each independent
* jointree item. These are the components to be joined together.
+ * Note that levels_needed == list_length(initial_rels).
*
* Returns the final level of join relations, i.e., the relation that is
* the result of joining all the original relations together.
+ * At least one implementation path must be provided for this relation and
+ * all required sub-relations.
+ *
+ * To support loadable plugins that modify planner behavior by changing the
+ * join searching algorithm, we provide a hook variable that lets a plugin
+ * replace or supplement this function. Any such hook must return the same
+ * final join relation as the standard code would, but it might have a
+ * different set of implementation paths attached, and only the sub-joinrels
+ * needed for these paths need have been instantiated.
+ *
+ * Note to plugin authors: the functions invoked during standard_join_search()
+ * modify root->join_rel_list and root->join_rel_hash. If you want to do more
+ * than one join-order search, you'll probably need to save and restore the
+ * original states of those data structures. See geqo_eval() for an example.
*/
-static RelOptInfo *
-make_one_rel_by_joins(Query *root, int levels_needed, List *initial_rels)
+RelOptInfo *
+standard_join_search(PlannerInfo *root, int levels_needed, List *initial_rels)
{
- List **joinitems;
int lev;
RelOptInfo *rel;
/*
- * We employ a simple "dynamic programming" algorithm: we first find
- * all ways to build joins of two jointree items, then all ways to
- * build joins of three items (from two-item joins and single items),
- * then four-item joins, and so on until we have considered all ways
- * to join all the items into one rel.
+ * This function cannot be invoked recursively within any one planning
+ * problem, so join_rel_level[] can't be in use already.
+ */
+ Assert(root->join_rel_level == NULL);
+
+ /*
+ * We employ a simple "dynamic programming" algorithm: we first find all
+ * ways to build joins of two jointree items, then all ways to build joins
+ * of three items (from two-item joins and single items), then four-item
+ * joins, and so on until we have considered all ways to join all the
+ * items into one rel.
*
- * joinitems[j] is a list of all the j-item rels. Initially we set
- * joinitems[1] to represent all the single-jointree-item relations.
+ * root->join_rel_level[j] is a list of all the j-item rels. Initially we
+ * set root->join_rel_level[1] to represent all the single-jointree-item
+ * relations.
*/
- joinitems = (List **) palloc0((levels_needed + 1) * sizeof(List *));
+ root->join_rel_level = (List **) palloc0((levels_needed + 1) * sizeof(List *));
- joinitems[1] = initial_rels;
+ root->join_rel_level[1] = initial_rels;
for (lev = 2; lev <= levels_needed; lev++)
{
- List *x;
+ ListCell *lc;
/*
* Determine all possible pairs of relations to be joined at this
* level, and build paths for making each one from every available
* pair of lower-level relations.
*/
- joinitems[lev] = make_rels_by_joins(root, lev, joinitems);
+ join_search_one_level(root, lev);
/*
* Do cleanup work on each just-processed rel.
*/
- foreach(x, joinitems[lev])
+ foreach(lc, root->join_rel_level[lev])
{
- rel = (RelOptInfo *) lfirst(x);
-
-#ifdef NOT_USED
-
- /*
- * * for each expensive predicate in each path in each
- * distinct rel, * consider doing pullup -- JMH
- */
- if (XfuncMode != XFUNC_NOPULL && XfuncMode != XFUNC_OFF)
- xfunc_trypullup(rel);
-#endif
+ rel = (RelOptInfo *) lfirst(lc);
/* Find and save the cheapest paths for this rel */
set_cheapest(rel);
/*
* We should have a single rel at the final level.
*/
- Assert(length(joinitems[levels_needed]) == 1);
+ if (root->join_rel_level[levels_needed] == NIL)
+ elog(ERROR, "failed to build any %d-way joins", levels_needed);
+ Assert(list_length(root->join_rel_level[levels_needed]) == 1);
- rel = (RelOptInfo *) lfirst(joinitems[levels_needed]);
+ rel = (RelOptInfo *) linitial(root->join_rel_level[levels_needed]);
+
+ root->join_rel_level = NULL;
return rel;
}
* 1. If the subquery has a LIMIT clause, we must not push down any quals,
* since that could change the set of rows returned.
*
- * 2. If the subquery contains EXCEPT or EXCEPT ALL set ops we cannot push
- * quals into it, because that would change the results.
+ * 2. If the subquery contains any window functions, we can't push quals
+ * into it, because that could change the results.
+ *
+ * 3. If the subquery contains EXCEPT or EXCEPT ALL set ops we cannot push
+ * quals into it, because that could change the results.
*
- * 3. For subqueries using UNION/UNION ALL/INTERSECT/INTERSECT ALL, we can
+ * 4. For subqueries using UNION/UNION ALL/INTERSECT/INTERSECT ALL, we can
* push quals into each component query, but the quals can only reference
* subquery columns that suffer no type coercions in the set operation.
* Otherwise there are possible semantic gotchas. So, we check the
if (subquery->limitOffset != NULL || subquery->limitCount != NULL)
return false;
+ /* Check point 2 */
+ if (subquery->hasWindowFuncs)
+ return false;
+
/* Are we at top level, or looking at a setop component? */
if (subquery == topquery)
{
* Compare tlist's datatypes against the list of set-operation result types.
* For any items that are different, mark the appropriate element of
* differentTypes[] to show that this column will have type conversions.
+ *
+ * We don't have to care about typmods here: the only allowed difference
+ * between set-op input and output typmods is input is a specific typmod
+ * and output is -1, and that does not require a coercion.
*/
static void
compare_tlist_datatypes(List *tlist, List *colTypes,
bool *differentTypes)
{
- List *i;
+ ListCell *l;
+ ListCell *colType = list_head(colTypes);
- foreach(i, tlist)
+ foreach(l, tlist)
{
- TargetEntry *tle = (TargetEntry *) lfirst(i);
+ TargetEntry *tle = (TargetEntry *) lfirst(l);
- if (tle->resdom->resjunk)
+ if (tle->resjunk)
continue; /* ignore resjunk columns */
- if (colTypes == NIL)
+ if (colType == NULL)
elog(ERROR, "wrong number of tlist entries");
- if (tle->resdom->restype != lfirsto(colTypes))
- differentTypes[tle->resdom->resno] = true;
- colTypes = lnext(colTypes);
+ if (exprType((Node *) tle->expr) != lfirst_oid(colType))
+ differentTypes[tle->resno] = true;
+ colType = lnext(colType);
}
- if (colTypes != NIL)
+ if (colType != NULL)
elog(ERROR, "wrong number of tlist entries");
}
* it will work correctly: sublinks will already have been transformed into
* subplans in the qual, but not in the subquery).
*
- * 2. The qual must not refer to any subquery output columns that were
+ * 2. The qual must not refer to the whole-row output of the subquery
+ * (since there is no easy way to name that within the subquery itself).
+ *
+ * 3. The qual must not refer to any subquery output columns that were
* found to have inconsistent types across a set operation tree by
* subquery_is_pushdown_safe().
*
- * 3. If the subquery uses DISTINCT ON, we must not push down any quals that
+ * 4. If the subquery uses DISTINCT ON, we must not push down any quals that
* refer to non-DISTINCT output columns, because that could change the set
- * of rows returned. This condition is vacuous for DISTINCT, because then
- * there are no non-DISTINCT output columns, but unfortunately it's fairly
- * expensive to tell the difference between DISTINCT and DISTINCT ON in the
- * parsetree representation. It's cheaper to just make sure all the Vars
- * in the qual refer to DISTINCT columns.
+ * of rows returned. (This condition is vacuous for DISTINCT, because then
+ * there are no non-DISTINCT output columns, so we needn't check. But note
+ * we are assuming that the qual can't distinguish values that the DISTINCT
+ * operator sees as equal. This is a bit shaky but we have no way to test
+ * for the case, and it's unlikely enough that we shouldn't refuse the
+ * optimization just because it could theoretically happen.)
*
- * 4. We must not push down any quals that refer to subselect outputs that
+ * 5. We must not push down any quals that refer to subselect outputs that
* return sets, else we'd introduce functions-returning-sets into the
* subquery's WHERE/HAVING quals.
+ *
+ * 6. We must not push down any quals that refer to subselect outputs that
+ * contain volatile functions, for fear of introducing strange results due
+ * to multiple evaluation of a volatile function.
*/
static bool
qual_is_pushdown_safe(Query *subquery, Index rti, Node *qual,
{
bool safe = true;
List *vars;
- List *vl;
+ ListCell *vl;
Bitmapset *tested = NULL;
/* Refuse subselects (point 1) */
return false;
/*
- * Examine all Vars used in clause; since it's a restriction clause,
- * all such Vars must refer to subselect output columns.
+ * It would be unsafe to push down window function calls, but at least for
+ * the moment we could never see any in a qual anyhow.
+ */
+ Assert(!contain_window_function(qual));
+
+ /*
+ * Examine all Vars used in clause; since it's a restriction clause, all
+ * such Vars must refer to subselect output columns.
*/
- vars = pull_var_clause(qual, false);
+ vars = pull_var_clause(qual, PVC_INCLUDE_PLACEHOLDERS);
foreach(vl, vars)
{
Var *var = (Var *) lfirst(vl);
TargetEntry *tle;
+ /*
+ * XXX Punt if we find any PlaceHolderVars in the restriction clause.
+ * It's not clear whether a PHV could safely be pushed down, and even
+ * less clear whether such a situation could arise in any cases of
+ * practical interest anyway. So for the moment, just refuse to push
+ * down.
+ */
+ if (!IsA(var, Var))
+ {
+ safe = false;
+ break;
+ }
+
Assert(var->varno == rti);
+ /* Check point 2 */
+ if (var->varattno == 0)
+ {
+ safe = false;
+ break;
+ }
+
/*
- * We use a bitmapset to avoid testing the same attno more than
- * once. (NB: this only works because subquery outputs can't have
- * negative attnos.)
+ * We use a bitmapset to avoid testing the same attno more than once.
+ * (NB: this only works because subquery outputs can't have negative
+ * attnos.)
*/
if (bms_is_member(var->varattno, tested))
continue;
tested = bms_add_member(tested, var->varattno);
- /* Check point 2 */
+ /* Check point 3 */
if (differentTypes[var->varattno])
{
safe = false;
/* Must find the tlist element referenced by the Var */
tle = get_tle_by_resno(subquery->targetList, var->varattno);
Assert(tle != NULL);
- Assert(!tle->resdom->resjunk);
+ Assert(!tle->resjunk);
- /* If subquery uses DISTINCT or DISTINCT ON, check point 3 */
- if (subquery->distinctClause != NIL &&
- !targetIsInSortList(tle, subquery->distinctClause))
+ /* If subquery uses DISTINCT ON, check point 4 */
+ if (subquery->hasDistinctOn &&
+ !targetIsInSortList(tle, InvalidOid, subquery->distinctClause))
{
/* non-DISTINCT column, so fail */
safe = false;
break;
}
- /* Refuse functions returning sets (point 4) */
+ /* Refuse functions returning sets (point 5) */
if (expression_returns_set((Node *) tle->expr))
{
safe = false;
break;
}
+
+ /* Refuse volatile functions (point 6) */
+ if (contain_volatile_functions((Node *) tle->expr))
+ {
+ safe = false;
+ break;
+ }
}
- freeList(vars);
+ list_free(vars);
bms_free(tested);
return safe;
* subquery_push_qual - push down a qual that we have determined is safe
*/
static void
-subquery_push_qual(Query *subquery, Index rti, Node *qual)
+subquery_push_qual(Query *subquery, RangeTblEntry *rte, Index rti, Node *qual)
{
if (subquery->setOperations != NULL)
{
/* Recurse to push it separately to each component query */
- recurse_push_qual(subquery->setOperations, subquery, rti, qual);
+ recurse_push_qual(subquery->setOperations, subquery,
+ rte, rti, qual);
}
else
{
/*
- * We need to replace Vars in the qual (which must refer to
- * outputs of the subquery) with copies of the subquery's
- * targetlist expressions. Note that at this point, any uplevel
- * Vars in the qual should have been replaced with Params, so they
- * need no work.
+ * We need to replace Vars in the qual (which must refer to outputs of
+ * the subquery) with copies of the subquery's targetlist expressions.
+ * Note that at this point, any uplevel Vars in the qual should have
+ * been replaced with Params, so they need no work.
*
* This step also ensures that when we are pushing into a setop tree,
* each component query gets its own copy of the qual.
*/
- qual = ResolveNew(qual, rti, 0,
+ qual = ResolveNew(qual, rti, 0, rte,
subquery->targetList,
- CMD_SELECT, 0);
- subquery->havingQual = make_and_qual(subquery->havingQual,
- qual);
+ CMD_SELECT, 0,
+ &subquery->hasSubLinks);
+
+ /*
+ * Now attach the qual to the proper place: normally WHERE, but if the
+ * subquery uses grouping or aggregation, put it in HAVING (since the
+ * qual really refers to the group-result rows).
+ */
+ if (subquery->hasAggs || subquery->groupClause || subquery->havingQual)
+ subquery->havingQual = make_and_qual(subquery->havingQual, qual);
+ else
+ subquery->jointree->quals =
+ make_and_qual(subquery->jointree->quals, qual);
/*
* We need not change the subquery's hasAggs or hasSublinks flags,
- * since we can't be pushing down any aggregates that weren't
- * there before, and we don't push down subselects at all.
+ * since we can't be pushing down any aggregates that weren't there
+ * before, and we don't push down subselects at all.
*/
}
}
*/
static void
recurse_push_qual(Node *setOp, Query *topquery,
- Index rti, Node *qual)
+ RangeTblEntry *rte, Index rti, Node *qual)
{
if (IsA(setOp, RangeTblRef))
{
RangeTblRef *rtr = (RangeTblRef *) setOp;
- RangeTblEntry *rte = rt_fetch(rtr->rtindex, topquery->rtable);
- Query *subquery = rte->subquery;
+ RangeTblEntry *subrte = rt_fetch(rtr->rtindex, topquery->rtable);
+ Query *subquery = subrte->subquery;
Assert(subquery != NULL);
- subquery_push_qual(subquery, rti, qual);
+ subquery_push_qual(subquery, rte, rti, qual);
}
else if (IsA(setOp, SetOperationStmt))
{
SetOperationStmt *op = (SetOperationStmt *) setOp;
- recurse_push_qual(op->larg, topquery, rti, qual);
- recurse_push_qual(op->rarg, topquery, rti, qual);
+ recurse_push_qual(op->larg, topquery, rte, rti, qual);
+ recurse_push_qual(op->rarg, topquery, rte, rti, qual);
}
else
{
}
static void
-print_restrictclauses(Query *root, List *clauses)
+print_restrictclauses(PlannerInfo *root, List *clauses)
{
- List *l;
+ ListCell *l;
foreach(l, clauses)
{
RestrictInfo *c = lfirst(l);
- print_expr((Node *) c->clause, root->rtable);
+ print_expr((Node *) c->clause, root->parse->rtable);
if (lnext(l))
printf(", ");
}
}
static void
-print_path(Query *root, Path *path, int indent)
+print_path(PlannerInfo *root, Path *path, int indent)
{
const char *ptype;
bool join = false;
case T_IndexPath:
ptype = "IdxScan";
break;
+ case T_BitmapHeapPath:
+ ptype = "BitmapHeapScan";
+ break;
+ case T_BitmapAndPath:
+ ptype = "BitmapAndPath";
+ break;
+ case T_BitmapOrPath:
+ ptype = "BitmapOrPath";
+ break;
case T_TidPath:
ptype = "TidScan";
break;
+ case T_ForeignPath:
+ ptype = "ForeignScan";
+ break;
case T_AppendPath:
ptype = "Append";
break;
+ case T_MergeAppendPath:
+ ptype = "MergeAppend";
+ break;
case T_ResultPath:
ptype = "Result";
- subpath = ((ResultPath *) path)->subpath;
break;
case T_MaterialPath:
ptype = "Material";
for (i = 0; i < indent; i++)
printf("\t");
printf(" pathkeys: ");
- print_pathkeys(path->pathkeys, root->rtable);
+ print_pathkeys(path->pathkeys, root->parse->rtable);
}
if (join)
{
MergePath *mp = (MergePath *) path;
- if (mp->outersortkeys || mp->innersortkeys)
- {
- for (i = 0; i < indent; i++)
- printf("\t");
- printf(" sortouter=%d sortinner=%d\n",
- ((mp->outersortkeys) ? 1 : 0),
- ((mp->innersortkeys) ? 1 : 0));
- }
+ for (i = 0; i < indent; i++)
+ printf("\t");
+ printf(" sortouter=%d sortinner=%d materializeinner=%d\n",
+ ((mp->outersortkeys) ? 1 : 0),
+ ((mp->innersortkeys) ? 1 : 0),
+ ((mp->materialize_inner) ? 1 : 0));
}
print_path(root, jp->outerjoinpath, indent + 1);
}
void
-debug_print_rel(Query *root, RelOptInfo *rel)
+debug_print_rel(PlannerInfo *root, RelOptInfo *rel)
{
- List *l;
+ ListCell *l;
printf("RELOPTINFO (");
print_relids(rel->relids);
printf("\n");
}
- foreach(l, rel->joininfo)
+ if (rel->joininfo)
{
- JoinInfo *j = (JoinInfo *) lfirst(l);
-
- printf("\tjoininfo (");
- print_relids(j->unjoined_relids);
- printf("): ");
- print_restrictclauses(root, j->jinfo_restrictinfo);
+ printf("\tjoininfo: ");
+ print_restrictclauses(root, rel->joininfo);
printf("\n");
}
projects / postgresql / blobdiff