#include <math.h>
#include "catalog/pg_class.h"
+#include "foreign/fdwapi.h"
#include "nodes/nodeFuncs.h"
#ifdef OPTIMIZER_DEBUG
#include "nodes/print.h"
join_search_hook_type join_search_hook = NULL;
+static void set_base_rel_sizes(PlannerInfo *root);
static void set_base_rel_pathlists(PlannerInfo *root);
+static void set_rel_size(PlannerInfo *root, RelOptInfo *rel,
+ Index rti, RangeTblEntry *rte);
static void set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
Index rti, RangeTblEntry *rte);
+static void set_plain_rel_size(PlannerInfo *root, RelOptInfo *rel,
+ RangeTblEntry *rte);
static void set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
RangeTblEntry *rte);
+static void set_foreign_size(PlannerInfo *root, RelOptInfo *rel,
+ RangeTblEntry *rte);
+static void set_foreign_pathlist(PlannerInfo *root, RelOptInfo *rel,
+ RangeTblEntry *rte);
+static void set_append_rel_size(PlannerInfo *root, RelOptInfo *rel,
+ Index rti, RangeTblEntry *rte);
static void set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
Index rti, RangeTblEntry *rte);
+static void generate_mergeappend_paths(PlannerInfo *root, RelOptInfo *rel,
+ List *live_childrels,
+ List *all_child_pathkeys);
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,
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);
make_one_rel(PlannerInfo *root, List *joinlist)
{
RelOptInfo *rel;
+ Index rti;
+
+ /*
+ * Construct the all_baserels Relids set.
+ */
+ root->all_baserels = NULL;
+ for (rti = 1; rti < root->simple_rel_array_size; rti++)
+ {
+ RelOptInfo *brel = root->simple_rel_array[rti];
+
+ /* there may be empty slots corresponding to non-baserel RTEs */
+ if (brel == NULL)
+ continue;
+
+ Assert(brel->relid == rti); /* sanity check on array */
+
+ /* ignore RTEs that are "other rels" */
+ if (brel->reloptkind != RELOPT_BASEREL)
+ continue;
+
+ root->all_baserels = bms_add_member(root->all_baserels, brel->relid);
+ }
/*
* Generate access paths for the base rels.
*/
+ set_base_rel_sizes(root);
set_base_rel_pathlists(root);
/*
/*
* The result should join all and only the query's base rels.
*/
-#ifdef USE_ASSERT_CHECKING
- {
- int num_base_rels = 0;
- Index rti;
+ Assert(bms_equal(rel->relids, root->all_baserels));
- for (rti = 1; rti < root->simple_rel_array_size; rti++)
- {
- RelOptInfo *brel = root->simple_rel_array[rti];
+ return rel;
+}
- if (brel == NULL)
- continue;
+/*
+ * set_base_rel_sizes
+ * Set the size estimates (rows and widths) for each base-relation entry.
+ *
+ * We do this in a separate pass over the base rels so that rowcount
+ * estimates are available for parameterized path generation.
+ */
+static void
+set_base_rel_sizes(PlannerInfo *root)
+{
+ Index rti;
- Assert(brel->relid == rti); /* sanity check on array */
+ for (rti = 1; rti < root->simple_rel_array_size; rti++)
+ {
+ RelOptInfo *rel = root->simple_rel_array[rti];
- /* ignore RTEs that are "other rels" */
- if (brel->reloptkind != RELOPT_BASEREL)
- continue;
+ /* there may be empty slots corresponding to non-baserel RTEs */
+ if (rel == NULL)
+ continue;
- Assert(bms_is_member(rti, rel->relids));
- num_base_rels++;
- }
+ Assert(rel->relid == rti); /* sanity check on array */
- Assert(bms_num_members(rel->relids) == num_base_rels);
- }
-#endif
+ /* ignore RTEs that are "other rels" */
+ if (rel->reloptkind != RELOPT_BASEREL)
+ continue;
- return rel;
+ set_rel_size(root, rel, rti, root->simple_rte_array[rti]);
+ }
}
/*
}
/*
- * set_rel_pathlist
- * Build access paths for a base relation
+ * set_rel_size
+ * Set size estimates for a base relation
*/
static void
-set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
- Index rti, RangeTblEntry *rte)
+set_rel_size(PlannerInfo *root, RelOptInfo *rel,
+ Index rti, RangeTblEntry *rte)
{
if (rel->reloptkind == RELOPT_BASEREL &&
relation_excluded_by_constraints(root, rel, rte))
* so set up a single dummy path for it. Here we only check this for
* regular baserels; if it's an otherrel, CE was already checked in
* set_append_rel_pathlist().
+ *
+ * In this case, we go ahead and set up the relation's path right away
+ * instead of leaving it for set_rel_pathlist to do. This is because
+ * we don't have a convention for marking a rel as dummy except by
+ * assigning a dummy path to it.
*/
set_dummy_rel_pathlist(rel);
}
else if (rte->inh)
{
/* It's an "append relation", process accordingly */
- set_append_rel_pathlist(root, rel, rti, rte);
+ set_append_rel_size(root, rel, rti, rte);
}
else
{
if (rte->relkind == RELKIND_FOREIGN_TABLE)
{
/* Foreign table */
- set_foreign_pathlist(root, rel, rte);
+ set_foreign_size(root, rel, rte);
}
else
{
/* Plain relation */
- set_plain_rel_pathlist(root, rel, rte);
+ set_plain_rel_size(root, rel, rte);
}
break;
case RTE_SUBQUERY:
- /* Subquery --- generate a separate plan for it */
+
+ /*
+ * Subqueries don't support making a choice between
+ * parameterized and unparameterized paths, so just go ahead
+ * and build their paths immediately.
+ */
set_subquery_pathlist(root, rel, rti, rte);
break;
case RTE_FUNCTION:
- /* RangeFunction --- generate a suitable path for it */
- set_function_pathlist(root, rel, rte);
+ set_function_size_estimates(root, rel);
break;
case RTE_VALUES:
- /* Values list --- generate a suitable path for it */
- set_values_pathlist(root, rel, rte);
+ set_values_size_estimates(root, rel);
break;
case RTE_CTE:
- /* CTE reference --- generate a suitable path for it */
+
+ /*
+ * CTEs don't support making a choice between parameterized
+ * and unparameterized paths, so just go ahead and build their
+ * paths immediately.
+ */
if (rte->self_reference)
set_worktable_pathlist(root, rel, rte);
else
break;
}
}
+}
+
+/*
+ * set_rel_pathlist
+ * Build access paths for a base relation
+ */
+static void
+set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
+ Index rti, RangeTblEntry *rte)
+{
+ if (IS_DUMMY_REL(rel))
+ {
+ /* We already proved the relation empty, so nothing more to do */
+ }
+ else if (rte->inh)
+ {
+ /* It's an "append relation", process accordingly */
+ set_append_rel_pathlist(root, rel, rti, rte);
+ }
+ else
+ {
+ switch (rel->rtekind)
+ {
+ case RTE_RELATION:
+ if (rte->relkind == RELKIND_FOREIGN_TABLE)
+ {
+ /* Foreign table */
+ set_foreign_pathlist(root, rel, rte);
+ }
+ else
+ {
+ /* Plain relation */
+ set_plain_rel_pathlist(root, rel, rte);
+ }
+ break;
+ case RTE_SUBQUERY:
+ /* Subquery --- fully handled during set_rel_size */
+ break;
+ case RTE_FUNCTION:
+ /* RangeFunction */
+ set_function_pathlist(root, rel, rte);
+ break;
+ case RTE_VALUES:
+ /* Values list */
+ set_values_pathlist(root, rel, rte);
+ break;
+ case RTE_CTE:
+ /* CTE reference --- fully handled during set_rel_size */
+ break;
+ default:
+ elog(ERROR, "unexpected rtekind: %d", (int) rel->rtekind);
+ break;
+ }
+ }
#ifdef OPTIMIZER_DEBUG
debug_print_rel(root, rel);
}
/*
- * set_plain_rel_pathlist
- * Build access paths for a plain relation (no subquery, no inheritance)
+ * set_plain_rel_size
+ * Set size estimates for a plain relation (no subquery, no inheritance)
*/
static void
-set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
+set_plain_rel_size(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
{
/*
* Test any partial indexes of rel for applicability. We must do this
check_partial_indexes(root, rel);
set_baserel_size_estimates(root, rel);
}
+}
+
+/*
+ * set_plain_rel_pathlist
+ * Build access paths for a plain relation (no subquery, no inheritance)
+ */
+static void
+set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
+{
+ Relids required_outer;
/*
- * Generate paths and add them to the rel's pathlist.
- *
- * Note: add_path() will discard any paths that are dominated by another
- * available path, keeping only those paths that are superior along at
- * least one dimension of cost or sortedness.
+ * We don't support pushing join clauses into the quals of a seqscan, but
+ * it could still have required parameterization due to LATERAL refs in
+ * its tlist. (That can only happen if the seqscan is on a relation
+ * pulled up out of a UNION ALL appendrel.)
*/
+ required_outer = rel->lateral_relids;
/* Consider sequential scan */
- add_path(rel, create_seqscan_path(root, rel));
+ add_path(rel, create_seqscan_path(root, rel, required_outer));
/* Consider index scans */
create_index_paths(root, rel);
}
/*
- * set_append_rel_pathlist
- * Build access paths for an "append relation"
+ * set_foreign_size
+ * Set size estimates for a foreign table RTE
+ */
+static void
+set_foreign_size(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
+{
+ /* Mark rel with estimated output rows, width, etc */
+ set_foreign_size_estimates(root, rel);
+
+ /* Get FDW routine pointers for the rel */
+ rel->fdwroutine = GetFdwRoutineByRelId(rte->relid);
+
+ /* Let FDW adjust the size estimates, if it can */
+ rel->fdwroutine->GetForeignRelSize(root, rel, rte->relid);
+}
+
+/*
+ * set_foreign_pathlist
+ * Build access paths for a foreign table RTE
+ */
+static void
+set_foreign_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
+{
+ /* Call the FDW's GetForeignPaths function to generate path(s) */
+ rel->fdwroutine->GetForeignPaths(root, rel, rte->relid);
+
+ /* Select cheapest path */
+ set_cheapest(rel);
+}
+
+/*
+ * set_append_rel_size
+ * Set size estimates for an "append relation"
*
* The passed-in rel and RTE represent the entire append relation. The
* relation's contents are computed by appending together the output of
* a good thing because their outputs are not the same size.
*/
static void
-set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
- Index rti, RangeTblEntry *rte)
+set_append_rel_size(PlannerInfo *root, RelOptInfo *rel,
+ Index rti, RangeTblEntry *rte)
{
int parentRTindex = rti;
- List *live_childrels = NIL;
- List *subpaths = NIL;
- List *all_child_pathkeys = NIL;
double parent_rows;
double parent_size;
double *parent_attrsizes;
nattrs = rel->max_attr - rel->min_attr + 1;
parent_attrsizes = (double *) palloc0(nattrs * sizeof(double));
- /*
- * Generate access paths for each member relation, and pick the cheapest
- * path for each one.
- */
foreach(l, root->append_rel_list)
{
AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
RelOptInfo *childrel;
List *childquals;
Node *childqual;
- ListCell *lcp;
ListCell *parentvars;
ListCell *childvars;
* reconstitute the RestrictInfo layer.
*/
childquals = get_all_actual_clauses(rel->baserestrictinfo);
- childquals = (List *) adjust_appendrel_attrs((Node *) childquals,
+ childquals = (List *) adjust_appendrel_attrs(root,
+ (Node *) childquals,
appinfo);
childqual = eval_const_expressions(root, (Node *)
make_ands_explicit(childquals));
{
/*
* 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.
+ * appendrel.
*/
set_dummy_rel_pathlist(childrel);
continue;
* CE failed, so finish copying/modifying targetlist and join quals.
*
* Note: the resulting childrel->reltargetlist may contain arbitrary
- * expressions, which normally would not occur in a reltargetlist.
- * That is okay because nothing outside of this routine will look at
- * the child rel's reltargetlist. We do have to cope with the case
- * while constructing attr_widths estimates below, though.
+ * expressions, which otherwise would not occur in a reltargetlist.
+ * Code that might be looking at an appendrel child must cope with
+ * such. Note in particular that "arbitrary expression" can include
+ * "Var belonging to another relation", due to LATERAL references.
*/
childrel->joininfo = (List *)
- adjust_appendrel_attrs((Node *) rel->joininfo,
+ adjust_appendrel_attrs(root,
+ (Node *) rel->joininfo,
appinfo);
childrel->reltargetlist = (List *)
- adjust_appendrel_attrs((Node *) rel->reltargetlist,
+ adjust_appendrel_attrs(root,
+ (Node *) rel->reltargetlist,
appinfo);
/*
*/
/*
- * Compute the child's access paths.
+ * Compute the child's size.
*/
- set_rel_pathlist(root, childrel, childRTindex, childRTE);
+ set_rel_size(root, childrel, childRTindex, childRTE);
/*
* It is possible that constraint exclusion detected a contradiction
- * within a child subquery, even though we didn't prove one above.
- * If what we got back was a dummy path, we can skip this child.
+ * within a child subquery, even though we didn't prove one above. If
+ * so, we can skip this child.
*/
- if (IS_DUMMY_PATH(childrel->cheapest_total_path))
+ if (IS_DUMMY_REL(childrel))
continue;
/*
- * Child is live, so add its cheapest access path to the Append path
- * we are constructing for the parent.
- */
- subpaths = accumulate_append_subpath(subpaths,
- childrel->cheapest_total_path);
-
- /* Remember which childrels are live, for MergeAppend logic below */
- live_childrels = lappend(live_childrels, childrel);
-
- /*
- * 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)
- {
- 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.
+ * Accumulate size information from each live child.
*/
if (childrel->rows > 0)
{
/*
* Accumulate per-column estimates too. We need not do anything
- * for PlaceHolderVars in the parent list. If child expression
+ * for PlaceHolderVars in the parent list. If child expression
* isn't a Var, or we didn't record a width estimate for it, we
* have to fall back on a datatype-based estimate.
*
int pndx = parentvar->varattno - rel->min_attr;
int32 child_width = 0;
- if (IsA(childvar, Var))
+ if (IsA(childvar, Var) &&
+ ((Var *) childvar)->varno == childrel->relid)
{
- int cndx = ((Var *) childvar)->varattno - childrel->min_attr;
+ int cndx = ((Var *) childvar)->varattno - childrel->min_attr;
child_width = childrel->attr_widths[cndx];
}
rel->tuples = parent_rows;
pfree(parent_attrsizes);
+}
+
+/*
+ * set_append_rel_pathlist
+ * Build access paths for an "append relation"
+ */
+static void
+set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
+ Index rti, RangeTblEntry *rte)
+{
+ int parentRTindex = rti;
+ List *live_childrels = NIL;
+ List *subpaths = NIL;
+ bool subpaths_valid = true;
+ List *all_child_pathkeys = NIL;
+ List *all_child_outers = NIL;
+ ListCell *l;
/*
- * 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.)
+ * Generate access paths for each member relation, and remember the
+ * cheapest path for each one. Also, identify all pathkeys (orderings)
+ * and parameterizations (required_outer sets) available for the member
+ * relations.
*/
- add_path(rel, (Path *) create_append_path(rel, subpaths));
+ foreach(l, root->append_rel_list)
+ {
+ AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
+ int childRTindex;
+ RangeTblEntry *childRTE;
+ RelOptInfo *childrel;
+ ListCell *lcp;
+
+ /* append_rel_list contains all append rels; ignore others */
+ if (appinfo->parent_relid != parentRTindex)
+ continue;
+
+ /* Re-locate the child RTE and RelOptInfo */
+ childRTindex = appinfo->child_relid;
+ childRTE = root->simple_rte_array[childRTindex];
+ childrel = root->simple_rel_array[childRTindex];
+
+ /*
+ * Compute the child's access paths.
+ */
+ set_rel_pathlist(root, childrel, childRTindex, childRTE);
+
+ /*
+ * If child is dummy, ignore it.
+ */
+ if (IS_DUMMY_REL(childrel))
+ continue;
+
+ /*
+ * Child is live, so add it to the live_childrels list for use below.
+ */
+ live_childrels = lappend(live_childrels, childrel);
+
+ /*
+ * If child has an unparameterized cheapest-total path, add that to
+ * the unparameterized Append path we are constructing for the parent.
+ * If not, there's no workable unparameterized path.
+ */
+ if (childrel->cheapest_total_path->param_info == NULL)
+ subpaths = accumulate_append_subpath(subpaths,
+ childrel->cheapest_total_path);
+ else
+ subpaths_valid = false;
+
+ /*
+ * Collect lists of all the available path orderings and
+ * parameterizations for all the children. We use these as a
+ * heuristic to indicate which sort orderings and parameterizations we
+ * should build Append and MergeAppend paths for.
+ */
+ foreach(lcp, childrel->pathlist)
+ {
+ Path *childpath = (Path *) lfirst(lcp);
+ List *childkeys = childpath->pathkeys;
+ Relids childouter = PATH_REQ_OUTER(childpath);
+
+ /* Unsorted paths don't contribute to pathkey list */
+ if (childkeys != NIL)
+ {
+ ListCell *lpk;
+ bool found = false;
+
+ /* 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);
+ }
+ }
+
+ /* Unparameterized paths don't contribute to param-set list */
+ if (childouter)
+ {
+ ListCell *lco;
+ bool found = false;
+
+ /* Have we already seen this param set? */
+ foreach(lco, all_child_outers)
+ {
+ Relids existing_outers = (Relids) lfirst(lco);
+
+ if (bms_equal(existing_outers, childouter))
+ {
+ found = true;
+ break;
+ }
+ }
+ if (!found)
+ {
+ /* No, so add it to all_child_outers */
+ all_child_outers = lappend(all_child_outers,
+ childouter);
+ }
+ }
+ }
+ }
/*
- * 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.
+ * If we found unparameterized paths for all children, build an unordered,
+ * unparameterized Append path for the rel. (Note: this is correct even
+ * if we have zero or one live subpath due to constraint exclusion.)
*/
- foreach(l, all_child_pathkeys)
+ if (subpaths_valid)
+ add_path(rel, (Path *) create_append_path(rel, subpaths, NULL));
+
+ /*
+ * Also build unparameterized MergeAppend paths based on the collected
+ * list of child pathkeys.
+ */
+ if (subpaths_valid)
+ generate_mergeappend_paths(root, rel, live_childrels,
+ all_child_pathkeys);
+
+ /*
+ * Build Append paths for each parameterization seen among the child rels.
+ * (This may look pretty expensive, but in most cases of practical
+ * interest, the child rels will expose mostly the same parameterizations,
+ * so that not that many cases actually get considered here.)
+ *
+ * The Append node itself cannot enforce quals, so all qual checking must
+ * be done in the child paths. This means that to have a parameterized
+ * Append path, we must have the exact same parameterization for each
+ * child path; otherwise some children might be failing to check the
+ * moved-down quals. To make them match up, we can try to increase the
+ * parameterization of lesser-parameterized paths.
+ */
+ foreach(l, all_child_outers)
{
- List *pathkeys = (List *) lfirst(l);
+ Relids required_outer = (Relids) lfirst(l);
+ ListCell *lcr;
+
+ /* Select the child paths for an Append with this parameterization */
+ subpaths = NIL;
+ subpaths_valid = true;
+ foreach(lcr, live_childrels)
+ {
+ RelOptInfo *childrel = (RelOptInfo *) lfirst(lcr);
+ Path *cheapest_total;
+
+ cheapest_total =
+ get_cheapest_path_for_pathkeys(childrel->pathlist,
+ NIL,
+ required_outer,
+ TOTAL_COST);
+ Assert(cheapest_total != NULL);
+
+ /* Children must have exactly the desired parameterization */
+ if (!bms_equal(PATH_REQ_OUTER(cheapest_total), required_outer))
+ {
+ cheapest_total = reparameterize_path(root, cheapest_total,
+ required_outer, 1.0);
+ if (cheapest_total == NULL)
+ {
+ subpaths_valid = false;
+ break;
+ }
+ }
+
+ subpaths = accumulate_append_subpath(subpaths, cheapest_total);
+ }
+
+ if (subpaths_valid)
+ add_path(rel, (Path *)
+ create_append_path(rel, subpaths, required_outer));
+ }
+
+ /* Select cheapest paths */
+ set_cheapest(rel);
+}
+
+/*
+ * generate_mergeappend_paths
+ * Generate MergeAppend paths for an append relation
+ *
+ * Generate a path for each ordering (pathkey list) appearing in
+ * all_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 case.
+ *
+ * We don't currently generate any parameterized MergeAppend paths. While
+ * it would not take much more code here to do so, it's very unclear that it
+ * is worth the planning cycles to investigate such paths: there's little
+ * use for an ordered path on the inside of a nestloop. In fact, it's likely
+ * that the current coding of add_path would reject such paths out of hand,
+ * because add_path gives no credit for sort ordering of parameterized paths,
+ * and a parameterized MergeAppend is going to be more expensive than the
+ * corresponding parameterized Append path. If we ever try harder to support
+ * parameterized mergejoin plans, it might be worth adding support for
+ * parameterized MergeAppends to feed such joins. (See notes in
+ * optimizer/README for why that might not ever happen, though.)
+ */
+static void
+generate_mergeappend_paths(PlannerInfo *root, RelOptInfo *rel,
+ List *live_childrels,
+ List *all_child_pathkeys)
+{
+ ListCell *lcp;
+
+ foreach(lcp, all_child_pathkeys)
+ {
+ List *pathkeys = (List *) lfirst(lcp);
List *startup_subpaths = NIL;
List *total_subpaths = NIL;
bool startup_neq_total = false;
cheapest_startup =
get_cheapest_path_for_pathkeys(childrel->pathlist,
pathkeys,
+ NULL,
STARTUP_COST);
cheapest_total =
get_cheapest_path_for_pathkeys(childrel->pathlist,
pathkeys,
+ NULL,
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 we can't find any paths with the right order just use the
+ * cheapest-total path; we'll have to sort it later.
*/
- if (cheapest_startup == NULL)
- cheapest_startup = childrel->cheapest_total_path;
- if (cheapest_total == NULL)
- cheapest_total = childrel->cheapest_total_path;
+ if (cheapest_startup == NULL || cheapest_total == NULL)
+ {
+ cheapest_startup = cheapest_total =
+ childrel->cheapest_total_path;
+ /* Assert we do have an unparameterized path for this child */
+ Assert(cheapest_total->param_info == NULL);
+ }
/*
* Notice whether we actually have different paths for the
add_path(rel, (Path *) create_merge_append_path(root,
rel,
startup_subpaths,
- pathkeys));
+ pathkeys,
+ NULL));
if (startup_neq_total)
add_path(rel, (Path *) create_merge_append_path(root,
rel,
total_subpaths,
- pathkeys));
+ pathkeys,
+ NULL));
}
-
- /* Select cheapest path */
- set_cheapest(rel);
}
/*
* 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).
+ * AppendPath with no members (see also IS_DUMMY_PATH/IS_DUMMY_REL macros).
*/
static void
set_dummy_rel_pathlist(RelOptInfo *rel)
rel->rows = 0;
rel->width = 0;
- add_path(rel, (Path *) create_append_path(rel, NIL));
+ /* Discard any pre-existing paths; no further need for them */
+ rel->pathlist = NIL;
+
+ add_path(rel, (Path *) create_append_path(rel, NIL, NULL));
/* Select cheapest path (pretty easy in this case...) */
set_cheapest(rel);
/*
* set_subquery_pathlist
* Build the (single) access path for a subquery RTE
+ *
+ * We don't currently support generating parameterized paths for subqueries
+ * by pushing join clauses down into them; it seems too expensive to re-plan
+ * the subquery multiple times to consider different alternatives. So the
+ * subquery will have exactly one path. (The path will be parameterized
+ * if the subquery contains LATERAL references, otherwise not.) Since there's
+ * no freedom of action here, there's no need for a separate set_subquery_size
+ * phase: we just make the path right away.
*/
static void
set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
{
Query *parse = root->parse;
Query *subquery = rte->subquery;
+ Relids required_outer;
bool *differentTypes;
double tuple_fraction;
PlannerInfo *subroot;
*/
subquery = copyObject(subquery);
+ /*
+ * If it's a LATERAL subquery, it might contain some Vars of the current
+ * query level, requiring it to be treated as parameterized, even though
+ * we don't support pushing down join quals into subqueries.
+ */
+ required_outer = rel->lateral_relids;
+
/* We need a workspace for keeping track of set-op type coercions */
differentTypes = (bool *)
palloc0((list_length(subquery->targetList) + 1) * sizeof(bool));
* pseudoconstant clauses; better to have the gating node above the
* subquery.
*
- * Also, if the sub-query has "security_barrier" flag, it means the
+ * Also, if the sub-query has the "security_barrier" flag, it means the
* sub-query originated from a view that must enforce row-level security.
- * We must not push down quals in order to avoid information leaks, either
- * via side-effects or error output.
+ * Then we must not push down quals that contain leaky functions.
*
* Non-pushed-down clauses will get evaluated as qpquals of the
* SubqueryScan node.
RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
Node *clause = (Node *) rinfo->clause;
- /*
- * XXX. You might wonder why we're testing rte->security_barrier
- * qual-by-qual here rather than hoisting the test up into the
- * surrounding if statement; after all, the answer will be the
- * same for all quals. The answer is that we expect to shortly
- * change this logic to allow pushing down some quals that use only
- * "leakproof" operators even through a security barrier.
- */
if (!rinfo->pseudoconstant &&
- !rte->security_barrier &&
+ (!rte->security_barrier ||
+ !contain_leaky_functions(clause)) &&
qual_is_pushdown_safe(subquery, rti, clause, differentTypes))
{
/* Push it down */
else
tuple_fraction = root->tuple_fraction;
+ /* plan_params should not be in use in current query level */
+ Assert(root->plan_params == NIL);
+
/* Generate the plan for the subquery */
rel->subplan = subquery_planner(root->glob, subquery,
root,
&subroot);
rel->subroot = subroot;
+ /* Isolate the params needed by this specific subplan */
+ rel->subplan_params = root->plan_params;
+ root->plan_params = NIL;
+
/*
- * It's possible that constraint exclusion proved the subquery empty.
- * If so, it's convenient to turn it back into a dummy path so that we
- * will recognize appropriate optimizations at this level.
+ * It's possible that constraint exclusion proved the subquery empty. If
+ * so, it's convenient to turn it back into a dummy path so that we will
+ * recognize appropriate optimizations at this level.
*/
if (is_dummy_plan(rel->subplan))
{
pathkeys = convert_subquery_pathkeys(root, rel, subroot->query_pathkeys);
/* Generate appropriate path */
- add_path(rel, create_subqueryscan_path(rel, pathkeys));
+ add_path(rel, create_subqueryscan_path(root, rel, pathkeys, required_outer));
/* Select cheapest path (pretty easy in this case...) */
set_cheapest(rel);
static void
set_function_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
{
- /* Mark rel with estimated output rows, width, etc */
- set_function_size_estimates(root, rel);
+ Relids required_outer;
+
+ /*
+ * We don't support pushing join clauses into the quals of a function
+ * scan, but it could still have required parameterization due to LATERAL
+ * refs in the function expression.
+ */
+ required_outer = rel->lateral_relids;
/* Generate appropriate path */
- add_path(rel, create_functionscan_path(root, rel));
+ add_path(rel, create_functionscan_path(root, rel, required_outer));
/* Select cheapest path (pretty easy in this case...) */
set_cheapest(rel);
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);
+ Relids required_outer;
+
+ /*
+ * We don't support pushing join clauses into the quals of a values scan,
+ * but it could still have required parameterization due to LATERAL refs
+ * in the values expressions.
+ */
+ required_outer = rel->lateral_relids;
/* Generate appropriate path */
- add_path(rel, create_valuesscan_path(root, rel));
+ add_path(rel, create_valuesscan_path(root, rel, required_outer));
/* 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
+ *
+ * There's no need for a separate set_cte_size phase, since we don't
+ * support join-qual-parameterized paths for CTEs.
*/
static void
set_cte_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
int ndx;
ListCell *lc;
int plan_id;
+ Relids required_outer;
/*
* Find the referenced CTE, and locate the plan previously made for it.
/* Mark rel with estimated output rows, width, etc */
set_cte_size_estimates(root, rel, cteplan);
+ /*
+ * We don't support pushing join clauses into the quals of a CTE scan, but
+ * it could still have required parameterization due to LATERAL refs in
+ * its tlist. (That can only happen if the CTE scan is on a relation
+ * pulled up out of a UNION ALL appendrel.)
+ */
+ required_outer = rel->lateral_relids;
+
/* Generate appropriate path */
- add_path(rel, create_ctescan_path(root, rel));
+ add_path(rel, create_ctescan_path(root, rel, required_outer));
/* 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
+ *
+ * There's no need for a separate set_worktable_size phase, since we don't
+ * support join-qual-parameterized paths for CTEs.
*/
static void
set_worktable_pathlist(PlannerInfo *root, RelOptInfo *rel, RangeTblEntry *rte)
Plan *cteplan;
PlannerInfo *cteroot;
Index levelsup;
+ Relids required_outer;
/*
* We need to find the non-recursive term's plan, which is in the plan
/* 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);
+ /*
+ * We don't support pushing join clauses into the quals of a worktable
+ * scan, but it could still have required parameterization due to LATERAL
+ * refs in its tlist. (That can only happen if the worktable scan is on a
+ * relation pulled up out of a UNION ALL appendrel. I'm not sure this is
+ * actually possible given the restrictions on recursive references, but
+ * it's easy enough to support.)
+ */
+ required_outer = rel->lateral_relids;
/* Generate appropriate path */
- add_path(rel, (Path *) create_foreignscan_path(root, rel));
+ add_path(rel, create_worktablescan_path(root, rel, required_outer));
/* Select cheapest path (pretty easy in this case...) */
set_cheapest(rel);
/*
* 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. (The same applies
+ * the moment we could never see any in a qual anyhow. (The same applies
* to aggregates, which we check for in pull_var_clause below.)
*/
Assert(!contain_window_function(qual));
printf("\tpath list:\n");
foreach(l, rel->pathlist)
print_path(root, lfirst(l), 1);
- printf("\n\tcheapest startup path:\n");
- print_path(root, rel->cheapest_startup_path, 1);
- printf("\n\tcheapest total path:\n");
- print_path(root, rel->cheapest_total_path, 1);
+ if (rel->cheapest_startup_path)
+ {
+ printf("\n\tcheapest startup path:\n");
+ print_path(root, rel->cheapest_startup_path, 1);
+ }
+ if (rel->cheapest_total_path)
+ {
+ printf("\n\tcheapest total path:\n");
+ print_path(root, rel->cheapest_total_path, 1);
+ }
printf("\n");
fflush(stdout);
}
projects / postgresql / blobdiff