* planner.c
* The query optimizer external interface.
*
- * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.243 2008/09/09 18:58:08 tgl Exp $
+ * src/backend/optimizer/plan/planner.c
*
*-------------------------------------------------------------------------
*/
#include <limits.h>
-#include "catalog/pg_operator.h"
+#include "access/htup_details.h"
#include "executor/executor.h"
#include "executor/nodeAgg.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
+#ifdef OPTIMIZER_DEBUG
+#include "nodes/print.h"
+#endif
#include "optimizer/clauses.h"
#include "optimizer/cost.h"
#include "optimizer/pathnode.h"
#include "optimizer/paths.h"
+#include "optimizer/plancat.h"
#include "optimizer/planmain.h"
#include "optimizer/planner.h"
#include "optimizer/prep.h"
#include "optimizer/subselect.h"
#include "optimizer/tlist.h"
-#include "optimizer/var.h"
-#ifdef OPTIMIZER_DEBUG
-#include "nodes/print.h"
-#endif
-#include "parser/parse_expr.h"
-#include "parser/parse_oper.h"
+#include "parser/analyze.h"
#include "parser/parsetree.h"
-#include "utils/lsyscache.h"
-#include "utils/syscache.h"
+#include "rewrite/rewriteManip.h"
+#include "utils/rel.h"
/* GUC parameter */
-double cursor_tuple_fraction = DEFAULT_CURSOR_TUPLE_FRACTION;
+double cursor_tuple_fraction = DEFAULT_CURSOR_TUPLE_FRACTION;
/* Hook for plugins to get control in planner() */
planner_hook_type planner_hook = NULL;
/* Expression kind codes for preprocess_expression */
-#define EXPRKIND_QUAL 0
-#define EXPRKIND_TARGET 1
-#define EXPRKIND_RTFUNC 2
-#define EXPRKIND_VALUES 3
-#define EXPRKIND_LIMIT 4
-#define EXPRKIND_APPINFO 5
+#define EXPRKIND_QUAL 0
+#define EXPRKIND_TARGET 1
+#define EXPRKIND_RTFUNC 2
+#define EXPRKIND_RTFUNC_LATERAL 3
+#define EXPRKIND_VALUES 4
+#define EXPRKIND_VALUES_LATERAL 5
+#define EXPRKIND_LIMIT 6
+#define EXPRKIND_APPINFO 7
+#define EXPRKIND_PHV 8
static Node *preprocess_expression(PlannerInfo *root, Node *expr, int kind);
static void preprocess_qual_conditions(PlannerInfo *root, Node *jtnode);
static Plan *inheritance_planner(PlannerInfo *root);
static Plan *grouping_planner(PlannerInfo *root, double tuple_fraction);
-static bool is_dummy_plan(Plan *plan);
+static void preprocess_rowmarks(PlannerInfo *root);
static double preprocess_limit(PlannerInfo *root,
double tuple_fraction,
int64 *offset_est, int64 *count_est);
static void preprocess_groupclause(PlannerInfo *root);
static bool choose_hashed_grouping(PlannerInfo *root,
double tuple_fraction, double limit_tuples,
+ double path_rows, int path_width,
Path *cheapest_path, Path *sorted_path,
- double dNumGroups, AggClauseCounts *agg_counts);
+ double dNumGroups, AggClauseCosts *agg_costs);
static bool choose_hashed_distinct(PlannerInfo *root,
- Plan *input_plan, List *input_pathkeys,
double tuple_fraction, double limit_tuples,
+ double path_rows, int path_width,
+ Cost cheapest_startup_cost, Cost cheapest_total_cost,
+ Cost sorted_startup_cost, Cost sorted_total_cost,
+ List *sorted_pathkeys,
double dNumDistinctRows);
static List *make_subplanTargetList(PlannerInfo *root, List *tlist,
AttrNumber **groupColIdx, bool *need_tlist_eval);
+static int get_grouping_column_index(Query *parse, TargetEntry *tle);
static void locate_grouping_columns(PlannerInfo *root,
List *tlist,
List *sub_tlist,
AttrNumber *groupColIdx);
static List *postprocess_setop_tlist(List *new_tlist, List *orig_tlist);
+static List *select_active_windows(PlannerInfo *root, WindowFuncLists *wflists);
+static List *add_volatile_sort_exprs(List *window_tlist, List *tlist,
+ List *activeWindows);
+static List *make_pathkeys_for_window(PlannerInfo *root, WindowClause *wc,
+ List *tlist, bool canonicalize);
+static void get_column_info_for_window(PlannerInfo *root, WindowClause *wc,
+ List *tlist,
+ int numSortCols, AttrNumber *sortColIdx,
+ int *partNumCols,
+ AttrNumber **partColIdx,
+ Oid **partOperators,
+ int *ordNumCols,
+ AttrNumber **ordColIdx,
+ Oid **ordOperators);
/*****************************************************************************
glob = makeNode(PlannerGlobal);
glob->boundParams = boundParams;
- glob->paramlist = NIL;
glob->subplans = NIL;
- glob->subrtables = NIL;
+ glob->subroots = NIL;
glob->rewindPlanIDs = NULL;
glob->finalrtable = NIL;
+ glob->finalrowmarks = NIL;
+ glob->resultRelations = NIL;
glob->relationOids = NIL;
glob->invalItems = NIL;
+ glob->nParamExec = 0;
+ glob->lastPHId = 0;
+ glob->lastRowMarkId = 0;
glob->transientPlan = false;
/* Determine what fraction of the plan is likely to be scanned */
tuple_fraction = cursor_tuple_fraction;
/*
- * We document cursor_tuple_fraction as simply being a fraction,
- * which means the edge cases 0 and 1 have to be treated specially
- * here. We convert 1 to 0 ("all the tuples") and 0 to a very small
- * fraction.
+ * We document cursor_tuple_fraction as simply being a fraction, which
+ * means the edge cases 0 and 1 have to be treated specially here. We
+ * convert 1 to 0 ("all the tuples") and 0 to a very small fraction.
*/
if (tuple_fraction >= 1.0)
tuple_fraction = 0.0;
}
/* primary planning entry point (may recurse for subqueries) */
- top_plan = subquery_planner(glob, parse, 1, tuple_fraction, &root);
+ top_plan = subquery_planner(glob, parse, NULL,
+ false, tuple_fraction, &root);
/*
* If creating a plan for a scrollable cursor, make sure it can run
/* final cleanup of the plan */
Assert(glob->finalrtable == NIL);
- top_plan = set_plan_references(glob, top_plan, root->parse->rtable);
+ Assert(glob->finalrowmarks == NIL);
+ Assert(glob->resultRelations == NIL);
+ top_plan = set_plan_references(root, top_plan);
/* ... and the subplans (both regular subplans and initplans) */
- Assert(list_length(glob->subplans) == list_length(glob->subrtables));
- forboth(lp, glob->subplans, lr, glob->subrtables)
+ Assert(list_length(glob->subplans) == list_length(glob->subroots));
+ forboth(lp, glob->subplans, lr, glob->subroots)
{
Plan *subplan = (Plan *) lfirst(lp);
- List *subrtable = (List *) lfirst(lr);
+ PlannerInfo *subroot = (PlannerInfo *) lfirst(lr);
- lfirst(lp) = set_plan_references(glob, subplan, subrtable);
+ lfirst(lp) = set_plan_references(subroot, subplan);
}
/* build the PlannedStmt result */
result = makeNode(PlannedStmt);
result->commandType = parse->commandType;
+ result->queryId = parse->queryId;
+ result->hasReturning = (parse->returningList != NIL);
+ result->hasModifyingCTE = parse->hasModifyingCTE;
result->canSetTag = parse->canSetTag;
result->transientPlan = glob->transientPlan;
result->planTree = top_plan;
result->rtable = glob->finalrtable;
- result->resultRelations = root->resultRelations;
+ result->resultRelations = glob->resultRelations;
result->utilityStmt = parse->utilityStmt;
- result->intoClause = parse->intoClause;
result->subplans = glob->subplans;
result->rewindPlanIDs = glob->rewindPlanIDs;
- result->returningLists = root->returningLists;
- result->rowMarks = parse->rowMarks;
+ result->rowMarks = glob->finalrowmarks;
result->relationOids = glob->relationOids;
result->invalItems = glob->invalItems;
- result->nParamExec = list_length(glob->paramlist);
+ result->nParamExec = glob->nParamExec;
return result;
}
*
* glob is the global state for the current planner run.
* parse is the querytree produced by the parser & rewriter.
- * level is the current recursion depth (1 at the top-level Query).
+ * parent_root is the immediate parent Query's info (NULL at the top level).
+ * hasRecursion is true if this is a recursive WITH query.
* tuple_fraction is the fraction of tuples we expect will be retrieved.
* tuple_fraction is interpreted as explained for grouping_planner, below.
*
*/
Plan *
subquery_planner(PlannerGlobal *glob, Query *parse,
- Index level, double tuple_fraction,
+ PlannerInfo *parent_root,
+ bool hasRecursion, double tuple_fraction,
PlannerInfo **subroot)
{
int num_old_subplans = list_length(glob->subplans);
root = makeNode(PlannerInfo);
root->parse = parse;
root->glob = glob;
- root->query_level = level;
+ root->query_level = parent_root ? parent_root->query_level + 1 : 1;
+ root->parent_root = parent_root;
+ root->plan_params = NIL;
root->planner_cxt = CurrentMemoryContext;
root->init_plans = NIL;
+ root->cte_plan_ids = NIL;
root->eq_classes = NIL;
root->append_rel_list = NIL;
+ root->rowMarks = NIL;
+ root->hasInheritedTarget = false;
+
+ root->hasRecursion = hasRecursion;
+ if (hasRecursion)
+ root->wt_param_id = SS_assign_special_param(root);
+ else
+ root->wt_param_id = -1;
+ root->non_recursive_plan = NULL;
+
+ /*
+ * If there is a WITH list, process each WITH query and build an initplan
+ * SubPlan structure for it.
+ */
+ if (parse->cteList)
+ SS_process_ctes(root);
/*
* Look for ANY and EXISTS SubLinks in WHERE and JOIN/ON clauses, and try
pull_up_sublinks(root);
/*
- * Scan the rangetable for set-returning functions, and inline them
- * if possible (producing subqueries that might get pulled up next).
+ * Scan the rangetable for set-returning functions, and inline them if
+ * possible (producing subqueries that might get pulled up next).
* Recursion issues here are handled in the same way as for SubLinks.
*/
inline_set_returning_functions(root);
/*
- * Check to see if any subqueries in the rangetable can be merged into
- * this query.
+ * Check to see if any subqueries in the jointree can be merged into this
+ * query.
*/
parse->jointree = (FromExpr *)
- pull_up_subqueries(root, (Node *) parse->jointree, false, false);
+ pull_up_subqueries(root, (Node *) parse->jointree);
+
+ /*
+ * If this is a simple UNION ALL query, flatten it into an appendrel. We
+ * do this now because it requires applying pull_up_subqueries to the leaf
+ * queries of the UNION ALL, which weren't touched above because they
+ * weren't referenced by the jointree (they will be after we do this).
+ */
+ if (parse->setOperations)
+ flatten_simple_union_all(root);
/*
* Detect whether any rangetable entries are RTE_JOIN kind; if not, we can
* avoid the expense of doing flatten_join_alias_vars(). Also check for
- * outer joins --- if none, we can skip reduce_outer_joins().
- * This must be done after we have done pull_up_subqueries, of course.
+ * outer joins --- if none, we can skip reduce_outer_joins(). And check
+ * for LATERAL RTEs, too. This must be done after we have done
+ * pull_up_subqueries(), of course.
*/
root->hasJoinRTEs = false;
+ root->hasLateralRTEs = false;
hasOuterJoins = false;
foreach(l, parse->rtable)
{
{
root->hasJoinRTEs = true;
if (IS_OUTER_JOIN(rte->jointype))
- {
hasOuterJoins = true;
- /* Can quit scanning once we find an outer join */
- break;
- }
}
+ if (rte->lateral)
+ root->hasLateralRTEs = true;
}
+ /*
+ * Preprocess RowMark information. We need to do this after subquery
+ * pullup (so that all non-inherited RTEs are present) and before
+ * inheritance expansion (so that the info is available for
+ * expand_inherited_tables to examine and modify).
+ */
+ preprocess_rowmarks(root);
+
/*
* Expand any rangetable entries that are inheritance sets into "append
* relations". This can add entries to the rangetable, but they must be
root->hasPseudoConstantQuals = false;
/*
- * Do expression preprocessing on targetlist and quals.
+ * Do expression preprocessing on targetlist and quals, as well as other
+ * random expressions in the querytree. Note that we do not need to
+ * handle sort/group expressions explicitly, because they are actually
+ * part of the targetlist.
*/
parse->targetList = (List *)
preprocess_expression(root, (Node *) parse->targetList,
parse->havingQual = preprocess_expression(root, parse->havingQual,
EXPRKIND_QUAL);
+ foreach(l, parse->windowClause)
+ {
+ WindowClause *wc = (WindowClause *) lfirst(l);
+
+ /* partitionClause/orderClause are sort/group expressions */
+ wc->startOffset = preprocess_expression(root, wc->startOffset,
+ EXPRKIND_LIMIT);
+ wc->endOffset = preprocess_expression(root, wc->endOffset,
+ EXPRKIND_LIMIT);
+ }
+
parse->limitOffset = preprocess_expression(root, parse->limitOffset,
EXPRKIND_LIMIT);
parse->limitCount = preprocess_expression(root, parse->limitCount,
preprocess_expression(root, (Node *) root->append_rel_list,
EXPRKIND_APPINFO);
- /* Also need to preprocess expressions for function and values RTEs */
+ /* Also need to preprocess expressions within RTEs */
foreach(l, parse->rtable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
+ int kind;
- if (rte->rtekind == RTE_FUNCTION)
- rte->funcexpr = preprocess_expression(root, rte->funcexpr,
- EXPRKIND_RTFUNC);
+ if (rte->rtekind == RTE_SUBQUERY)
+ {
+ /*
+ * We don't want to do all preprocessing yet on the subquery's
+ * expressions, since that will happen when we plan it. But if it
+ * contains any join aliases of our level, those have to get
+ * expanded now, because planning of the subquery won't do it.
+ * That's only possible if the subquery is LATERAL.
+ */
+ if (rte->lateral && root->hasJoinRTEs)
+ rte->subquery = (Query *)
+ flatten_join_alias_vars(root, (Node *) rte->subquery);
+ }
+ else if (rte->rtekind == RTE_FUNCTION)
+ {
+ /* Preprocess the function expression fully */
+ kind = rte->lateral ? EXPRKIND_RTFUNC_LATERAL : EXPRKIND_RTFUNC;
+ rte->funcexpr = preprocess_expression(root, rte->funcexpr, kind);
+ }
else if (rte->rtekind == RTE_VALUES)
+ {
+ /* Preprocess the values lists fully */
+ kind = rte->lateral ? EXPRKIND_VALUES_LATERAL : EXPRKIND_VALUES;
rte->values_lists = (List *)
- preprocess_expression(root, (Node *) rte->values_lists,
- EXPRKIND_VALUES);
+ preprocess_expression(root, (Node *) rte->values_lists, kind);
+ }
}
/*
rt_fetch(parse->resultRelation, parse->rtable)->inh)
plan = inheritance_planner(root);
else
+ {
plan = grouping_planner(root, tuple_fraction);
+ /* If it's not SELECT, we need a ModifyTable node */
+ if (parse->commandType != CMD_SELECT)
+ {
+ List *returningLists;
+ List *rowMarks;
+
+ /*
+ * Set up the RETURNING list-of-lists, if needed.
+ */
+ if (parse->returningList)
+ returningLists = list_make1(parse->returningList);
+ else
+ returningLists = NIL;
+
+ /*
+ * If there was a FOR UPDATE/SHARE clause, the LockRows node will
+ * have dealt with fetching non-locked marked rows, else we need
+ * to have ModifyTable do that.
+ */
+ if (parse->rowMarks)
+ rowMarks = NIL;
+ else
+ rowMarks = root->rowMarks;
+
+ plan = (Plan *) make_modifytable(parse->commandType,
+ parse->canSetTag,
+ list_make1_int(parse->resultRelation),
+ list_make1(plan),
+ returningLists,
+ rowMarks,
+ SS_assign_special_param(root));
+ }
+ }
/*
- * If any subplans were generated, or if we're inside a subplan, build
- * initPlan list and extParam/allParam sets for plan nodes, and attach the
- * initPlans to the top plan node.
+ * If any subplans were generated, or if there are any parameters to worry
+ * about, build initPlan list and extParam/allParam sets for plan nodes,
+ * and attach the initPlans to the top plan node.
*/
if (list_length(glob->subplans) != num_old_subplans ||
- root->query_level > 1)
+ root->glob->nParamExec > 0)
SS_finalize_plan(root, plan, true);
/* Return internal info if caller wants it */
* preprocess_expression
* Do subquery_planner's preprocessing work for an expression,
* which can be a targetlist, a WHERE clause (including JOIN/ON
- * conditions), or a HAVING clause.
+ * conditions), a HAVING clause, or a few other things.
*/
static Node *
preprocess_expression(PlannerInfo *root, Node *expr, int kind)
/*
* If the query has any join RTEs, replace join alias variables with
- * base-relation variables. We must do this before sublink processing,
- * else sublinks expanded out from join aliases wouldn't get processed. We
- * can skip it in VALUES lists, however, since they can't contain any Vars
- * at all.
+ * base-relation variables. We must do this before sublink processing,
+ * else sublinks expanded out from join aliases would not get processed.
+ * We can skip it in non-lateral RTE functions and VALUES lists, however,
+ * since they can't contain any Vars of the current query level.
*/
- if (root->hasJoinRTEs && kind != EXPRKIND_VALUES)
+ if (root->hasJoinRTEs &&
+ !(kind == EXPRKIND_RTFUNC || kind == EXPRKIND_VALUES))
expr = flatten_join_alias_vars(root, expr);
/*
* Simplify constant expressions.
*
+ * Note: an essential effect of this is to convert named-argument function
+ * calls to positional notation and insert the current actual values of
+ * any default arguments for functions. To ensure that happens, we *must*
+ * process all expressions here. Previous PG versions sometimes skipped
+ * const-simplification if it didn't seem worth the trouble, but we can't
+ * do that anymore.
+ *
* Note: this also flattens nested AND and OR expressions into N-argument
* form. All processing of a qual expression after this point must be
* careful to maintain AND/OR flatness --- that is, do not generate a tree
* with AND directly under AND, nor OR directly under OR.
- *
- * Because this is a relatively expensive process, we skip it when the
- * query is trivial, such as "SELECT 2+2;" or "INSERT ... VALUES()". The
- * expression will only be evaluated once anyway, so no point in
- * pre-simplifying; we can't execute it any faster than the executor can,
- * and we will waste cycles copying the tree. Notice however that we
- * still must do it for quals (to get AND/OR flatness); and if we are in a
- * subquery we should not assume it will be done only once.
- *
- * For VALUES lists we never do this at all, again on the grounds that we
- * should optimize for one-time evaluation.
*/
- if (kind != EXPRKIND_VALUES &&
- (root->parse->jointree->fromlist != NIL ||
- kind == EXPRKIND_QUAL ||
- root->query_level > 1))
- expr = eval_const_expressions(root, expr);
+ expr = eval_const_expressions(root, expr);
/*
* If it's a qual or havingQual, canonicalize it.
(int) nodeTag(jtnode));
}
+/*
+ * preprocess_phv_expression
+ * Do preprocessing on a PlaceHolderVar expression that's been pulled up.
+ *
+ * If a LATERAL subquery references an output of another subquery, and that
+ * output must be wrapped in a PlaceHolderVar because of an intermediate outer
+ * join, then we'll push the PlaceHolderVar expression down into the subquery
+ * and later pull it back up during find_lateral_references, which runs after
+ * subquery_planner has preprocessed all the expressions that were in the
+ * current query level to start with. So we need to preprocess it then.
+ */
+Expr *
+preprocess_phv_expression(PlannerInfo *root, Expr *expr)
+{
+ return (Expr *) preprocess_expression(root, (Node *) expr, EXPRKIND_PHV);
+}
+
/*
* inheritance_planner
* Generate a plan in the case where the result relation is an
* is an inheritance set. Source inheritance is expanded at the bottom of the
* plan tree (see allpaths.c), but target inheritance has to be expanded at
* the top. The reason is that for UPDATE, each target relation needs a
- * different targetlist matching its own column set. Also, for both UPDATE
- * and DELETE, the executor needs the Append plan node at the top, else it
- * can't keep track of which table is the current target table. Fortunately,
+ * different targetlist matching its own column set. Fortunately,
* the UPDATE/DELETE target can never be the nullable side of an outer join,
* so it's OK to generate the plan this way.
*
{
Query *parse = root->parse;
int parentRTindex = parse->resultRelation;
+ List *final_rtable = NIL;
+ int save_rel_array_size = 0;
+ RelOptInfo **save_rel_array = NULL;
List *subplans = NIL;
List *resultRelations = NIL;
List *returningLists = NIL;
- List *rtable = NIL;
- List *tlist = NIL;
- PlannerInfo subroot;
- ListCell *l;
+ List *rowMarks;
+ ListCell *lc;
- foreach(l, root->append_rel_list)
+ /*
+ * We generate a modified instance of the original Query for each target
+ * relation, plan that, and put all the plans into a list that will be
+ * controlled by a single ModifyTable node. All the instances share the
+ * same rangetable, but each instance must have its own set of subquery
+ * RTEs within the finished rangetable because (1) they are likely to get
+ * scribbled on during planning, and (2) it's not inconceivable that
+ * subqueries could get planned differently in different cases. We need
+ * not create duplicate copies of other RTE kinds, in particular not the
+ * target relations, because they don't have either of those issues. Not
+ * having to duplicate the target relations is important because doing so
+ * (1) would result in a rangetable of length O(N^2) for N targets, with
+ * at least O(N^3) work expended here; and (2) would greatly complicate
+ * management of the rowMarks list.
+ */
+ foreach(lc, root->append_rel_list)
{
- AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
+ AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(lc);
+ PlannerInfo subroot;
Plan *subplan;
+ Index rti;
/* append_rel_list contains all append rels; ignore others */
if (appinfo->parent_relid != parentRTindex)
continue;
/*
- * Generate modified query with this rel as target.
+ * We need a working copy of the PlannerInfo so that we can control
+ * propagation of information back to the main copy.
*/
memcpy(&subroot, root, sizeof(PlannerInfo));
+
+ /*
+ * Generate modified query with this rel as target. We first apply
+ * adjust_appendrel_attrs, which copies the Query and changes
+ * references to the parent RTE to refer to the current child RTE,
+ * then fool around with subquery RTEs.
+ */
subroot.parse = (Query *)
- adjust_appendrel_attrs((Node *) parse,
+ adjust_appendrel_attrs(root,
+ (Node *) parse,
appinfo);
- subroot.init_plans = NIL;
- /* There shouldn't be any OJ info to translate, as yet */
+
+ /*
+ * The rowMarks list might contain references to subquery RTEs, so
+ * make a copy that we can apply ChangeVarNodes to. (Fortunately, the
+ * executor doesn't need to see the modified copies --- we can just
+ * pass it the original rowMarks list.)
+ */
+ subroot.rowMarks = (List *) copyObject(root->rowMarks);
+
+ /*
+ * Add placeholders to the child Query's rangetable list to fill the
+ * RT indexes already reserved for subqueries in previous children.
+ * These won't be referenced, so there's no need to make them very
+ * valid-looking.
+ */
+ while (list_length(subroot.parse->rtable) < list_length(final_rtable))
+ subroot.parse->rtable = lappend(subroot.parse->rtable,
+ makeNode(RangeTblEntry));
+
+ /*
+ * If this isn't the first child Query, generate duplicates of all
+ * subquery RTEs, and adjust Var numbering to reference the
+ * duplicates. To simplify the loop logic, we scan the original rtable
+ * not the copy just made by adjust_appendrel_attrs; that should be OK
+ * since subquery RTEs couldn't contain any references to the target
+ * rel.
+ */
+ if (final_rtable != NIL)
+ {
+ ListCell *lr;
+
+ rti = 1;
+ foreach(lr, parse->rtable)
+ {
+ RangeTblEntry *rte = (RangeTblEntry *) lfirst(lr);
+
+ if (rte->rtekind == RTE_SUBQUERY)
+ {
+ Index newrti;
+
+ /*
+ * The RTE can't contain any references to its own RT
+ * index, so we can save a few cycles by applying
+ * ChangeVarNodes before we append the RTE to the
+ * rangetable.
+ */
+ newrti = list_length(subroot.parse->rtable) + 1;
+ ChangeVarNodes((Node *) subroot.parse, rti, newrti, 0);
+ ChangeVarNodes((Node *) subroot.rowMarks, rti, newrti, 0);
+ rte = copyObject(rte);
+ subroot.parse->rtable = lappend(subroot.parse->rtable,
+ rte);
+ }
+ rti++;
+ }
+ }
+
+ /* We needn't modify the child's append_rel_list */
+ /* There shouldn't be any OJ or LATERAL info to translate, as yet */
Assert(subroot.join_info_list == NIL);
+ Assert(subroot.lateral_info_list == NIL);
+ /* and we haven't created PlaceHolderInfos, either */
+ Assert(subroot.placeholder_list == NIL);
+ /* hack to mark target relation as an inheritance partition */
+ subroot.hasInheritedTarget = true;
/* Generate plan */
subplan = grouping_planner(&subroot, 0.0 /* retrieve all tuples */ );
/*
* If this child rel was excluded by constraint exclusion, exclude it
- * from the plan.
+ * from the result plan.
*/
if (is_dummy_plan(subplan))
continue;
- /* Save rtable and tlist from first rel for use below */
- if (subplans == NIL)
+ subplans = lappend(subplans, subplan);
+
+ /*
+ * If this is the first non-excluded child, its post-planning rtable
+ * becomes the initial contents of final_rtable; otherwise, append
+ * just its modified subquery RTEs to final_rtable.
+ */
+ if (final_rtable == NIL)
+ final_rtable = subroot.parse->rtable;
+ else
+ final_rtable = list_concat(final_rtable,
+ list_copy_tail(subroot.parse->rtable,
+ list_length(final_rtable)));
+
+ /*
+ * We need to collect all the RelOptInfos from all child plans into
+ * the main PlannerInfo, since setrefs.c will need them. We use the
+ * last child's simple_rel_array (previous ones are too short), so we
+ * have to propagate forward the RelOptInfos that were already built
+ * in previous children.
+ */
+ Assert(subroot.simple_rel_array_size >= save_rel_array_size);
+ for (rti = 1; rti < save_rel_array_size; rti++)
{
- rtable = subroot.parse->rtable;
- tlist = subplan->targetlist;
- }
+ RelOptInfo *brel = save_rel_array[rti];
- subplans = lappend(subplans, subplan);
+ if (brel)
+ subroot.simple_rel_array[rti] = brel;
+ }
+ save_rel_array_size = subroot.simple_rel_array_size;
+ save_rel_array = subroot.simple_rel_array;
/* Make sure any initplans from this rel get into the outer list */
- root->init_plans = list_concat(root->init_plans, subroot.init_plans);
+ root->init_plans = subroot.init_plans;
- /* Build target-relations list for the executor */
+ /* Build list of target-relation RT indexes */
resultRelations = lappend_int(resultRelations, appinfo->child_relid);
/* Build list of per-relation RETURNING targetlists */
if (parse->returningList)
- {
- Assert(list_length(subroot.returningLists) == 1);
- returningLists = list_concat(returningLists,
- subroot.returningLists);
- }
+ returningLists = lappend(returningLists,
+ subroot.parse->returningList);
}
- root->resultRelations = resultRelations;
- root->returningLists = returningLists;
-
/* Mark result as unordered (probably unnecessary) */
root->query_pathkeys = NIL;
/*
- * If we managed to exclude every child rel, return a dummy plan
+ * If we managed to exclude every child rel, return a dummy plan; it
+ * doesn't even need a ModifyTable node.
*/
if (subplans == NIL)
{
- root->resultRelations = list_make1_int(parentRTindex);
/* although dummy, it must have a valid tlist for executor */
+ List *tlist;
+
tlist = preprocess_targetlist(root, parse->targetList);
return (Plan *) make_result(root,
tlist,
}
/*
- * Planning might have modified the rangetable, due to changes of the
- * Query structures inside subquery RTEs. We have to ensure that this
- * gets propagated back to the master copy. But can't do this until we
- * are done planning, because all the calls to grouping_planner need
- * virgin sub-Queries to work from. (We are effectively assuming that
- * sub-Queries will get planned identically each time, or at least that
- * the impacts on their rangetables will be the same each time.)
- *
- * XXX should clean this up someday
+ * Put back the final adjusted rtable into the master copy of the Query.
*/
- parse->rtable = rtable;
+ parse->rtable = final_rtable;
+ root->simple_rel_array_size = save_rel_array_size;
+ root->simple_rel_array = save_rel_array;
- /* Suppress Append if there's only one surviving child rel */
- if (list_length(subplans) == 1)
- return (Plan *) linitial(subplans);
-
- return (Plan *) make_append(subplans, true, tlist);
+ /*
+ * If there was a FOR UPDATE/SHARE clause, the LockRows node will have
+ * dealt with fetching non-locked marked rows, else we need to have
+ * ModifyTable do that.
+ */
+ if (parse->rowMarks)
+ rowMarks = NIL;
+ else
+ rowMarks = root->rowMarks;
+
+ /* And last, tack on a ModifyTable node to do the UPDATE/DELETE work */
+ return (Plan *) make_modifytable(parse->commandType,
+ parse->canSetTag,
+ resultRelations,
+ subplans,
+ returningLists,
+ rowMarks,
+ SS_assign_special_param(root));
}
/*--------------------
Plan *result_plan;
List *current_pathkeys;
double dNumGroups = 0;
+ bool use_hashed_distinct = false;
+ bool tested_hashed_distinct = false;
/* Tweak caller-supplied tuple_fraction if have LIMIT/OFFSET */
if (parse->limitCount || parse->limitOffset)
/*
* If there's a top-level ORDER BY, assume we have to fetch all the
* tuples. This might be too simplistic given all the hackery below
- * to possibly avoid the sort; but the odds of accurate estimates
- * here are pretty low anyway.
+ * to possibly avoid the sort; but the odds of accurate estimates here
+ * are pretty low anyway.
*/
if (parse->sortClause)
tuple_fraction = 0.0;
/*
* Construct the plan for set operations. The result will not need
- * any work except perhaps a top-level sort and/or LIMIT.
+ * any work except perhaps a top-level sort and/or LIMIT. Note that
+ * any special work for recursive unions is the responsibility of
+ * plan_set_operations.
*/
result_plan = plan_set_operations(root, tuple_fraction,
&set_sortclauses);
{
/* No set operations, do regular planning */
List *sub_tlist;
+ double sub_limit_tuples;
AttrNumber *groupColIdx = NULL;
bool need_tlist_eval = true;
- QualCost tlist_cost;
Path *cheapest_path;
Path *sorted_path;
Path *best_path;
long numGroups = 0;
- AggClauseCounts agg_counts;
+ AggClauseCosts agg_costs;
int numGroupCols;
+ double path_rows;
+ int path_width;
bool use_hashed_grouping = false;
+ WindowFuncLists *wflists = NULL;
+ List *activeWindows = NIL;
- MemSet(&agg_counts, 0, sizeof(AggClauseCounts));
+ MemSet(&agg_costs, 0, sizeof(AggClauseCosts));
+
+ /* A recursive query should always have setOperations */
+ Assert(!root->hasRecursion);
/* Preprocess GROUP BY clause, if any */
if (parse->groupClause)
/* Preprocess targetlist */
tlist = preprocess_targetlist(root, tlist);
+ /*
+ * Locate any window functions in the tlist. (We don't need to look
+ * anywhere else, since expressions used in ORDER BY will be in there
+ * too.) Note that they could all have been eliminated by constant
+ * folding, in which case we don't need to do any more work.
+ */
+ if (parse->hasWindowFuncs)
+ {
+ wflists = find_window_functions((Node *) tlist,
+ list_length(parse->windowClause));
+ if (wflists->numWindowFuncs > 0)
+ activeWindows = select_active_windows(root, wflists);
+ else
+ parse->hasWindowFuncs = false;
+ }
+
/*
* Generate appropriate target list for subplan; may be different from
* tlist if grouping or aggregation is needed.
sub_tlist = make_subplanTargetList(root, tlist,
&groupColIdx, &need_tlist_eval);
+ /*
+ * Do aggregate preprocessing, if the query has any aggs.
+ *
+ * Note: think not that we can turn off hasAggs if we find no aggs. It
+ * is possible for constant-expression simplification to remove all
+ * explicit references to aggs, but we still have to follow the
+ * aggregate semantics (eg, producing only one output row).
+ */
+ if (parse->hasAggs)
+ {
+ /*
+ * Collect statistics about aggregates for estimating costs. Note:
+ * we do not attempt to detect duplicate aggregates here; a
+ * somewhat-overestimated cost is okay for our present purposes.
+ */
+ count_agg_clauses(root, (Node *) tlist, &agg_costs);
+ count_agg_clauses(root, parse->havingQual, &agg_costs);
+
+ /*
+ * Preprocess MIN/MAX aggregates, if any. Note: be careful about
+ * adding logic between here and the optimize_minmax_aggregates
+ * call. Anything that is needed in MIN/MAX-optimizable cases
+ * will have to be duplicated in planagg.c.
+ */
+ preprocess_minmax_aggregates(root, tlist);
+ }
+
/*
* Calculate pathkeys that represent grouping/ordering requirements.
* Stash them in PlannerInfo so that query_planner can canonicalize
- * them after EquivalenceClasses have been formed. The sortClause
- * is certainly sort-able, but GROUP BY and DISTINCT might not be,
- * in which case we just leave their pathkeys empty.
+ * them after EquivalenceClasses have been formed. The sortClause is
+ * certainly sort-able, but GROUP BY and DISTINCT might not be, in
+ * which case we just leave their pathkeys empty.
*/
if (parse->groupClause &&
grouping_is_sortable(parse->groupClause))
else
root->group_pathkeys = NIL;
+ /* We consider only the first (bottom) window in pathkeys logic */
+ if (activeWindows != NIL)
+ {
+ WindowClause *wc = (WindowClause *) linitial(activeWindows);
+
+ root->window_pathkeys = make_pathkeys_for_window(root,
+ wc,
+ tlist,
+ false);
+ }
+ else
+ root->window_pathkeys = NIL;
+
if (parse->distinctClause &&
grouping_is_sortable(parse->distinctClause))
root->distinct_pathkeys =
tlist,
false);
- /*
- * Will need actual number of aggregates for estimating costs.
- *
- * Note: we do not attempt to detect duplicate aggregates here; a
- * somewhat-overestimated count is okay for our present purposes.
- *
- * Note: think not that we can turn off hasAggs if we find no aggs. It
- * is possible for constant-expression simplification to remove all
- * explicit references to aggs, but we still have to follow the
- * aggregate semantics (eg, producing only one output row).
- */
- if (parse->hasAggs)
- {
- count_agg_clauses((Node *) tlist, &agg_counts);
- count_agg_clauses(parse->havingQual, &agg_counts);
- }
-
/*
* Figure out whether we want a sorted result from query_planner.
*
* If we have a sortable GROUP BY clause, then we want a result sorted
- * properly for grouping. Otherwise, if there's a sortable DISTINCT
- * clause that's more rigorous than the ORDER BY clause, we try to
- * produce output that's sufficiently well sorted for the DISTINCT.
- * Otherwise, if there is an ORDER BY clause, we want to sort by the
- * ORDER BY clause.
+ * properly for grouping. Otherwise, if we have window functions to
+ * evaluate, we try to sort for the first window. Otherwise, if
+ * there's a sortable DISTINCT clause that's more rigorous than the
+ * ORDER BY clause, we try to produce output that's sufficiently well
+ * sorted for the DISTINCT. Otherwise, if there is an ORDER BY
+ * clause, we want to sort by the ORDER BY clause.
*
* Note: if we have both ORDER BY and GROUP BY, and ORDER BY is a
* superset of GROUP BY, it would be tempting to request sort by ORDER
* BY --- but that might just leave us failing to exploit an available
- * sort order at all. Needs more thought. The choice for DISTINCT
+ * sort order at all. Needs more thought. The choice for DISTINCT
* versus ORDER BY is much easier, since we know that the parser
* ensured that one is a superset of the other.
*/
if (root->group_pathkeys)
root->query_pathkeys = root->group_pathkeys;
+ else if (root->window_pathkeys)
+ root->query_pathkeys = root->window_pathkeys;
else if (list_length(root->distinct_pathkeys) >
list_length(root->sort_pathkeys))
root->query_pathkeys = root->distinct_pathkeys;
else
root->query_pathkeys = NIL;
+ /*
+ * Figure out whether there's a hard limit on the number of rows that
+ * query_planner's result subplan needs to return. Even if we know a
+ * hard limit overall, it doesn't apply if the query has any
+ * grouping/aggregation operations.
+ */
+ if (parse->groupClause ||
+ parse->distinctClause ||
+ parse->hasAggs ||
+ parse->hasWindowFuncs ||
+ root->hasHavingQual)
+ sub_limit_tuples = -1.0;
+ else
+ sub_limit_tuples = limit_tuples;
+
/*
* Generate the best unsorted and presorted paths for this Query (but
* note there may not be any presorted path). query_planner will also
* estimate the number of groups in the query, and canonicalize all
* the pathkeys.
*/
- query_planner(root, sub_tlist, tuple_fraction, limit_tuples,
+ query_planner(root, sub_tlist, tuple_fraction, sub_limit_tuples,
&cheapest_path, &sorted_path, &dNumGroups);
/*
- * If grouping, decide whether to use sorted or hashed grouping.
+ * Extract rowcount and width estimates for possible use in grouping
+ * decisions. Beware here of the possibility that
+ * cheapest_path->parent is NULL (ie, there is no FROM clause).
*/
- if (parse->groupClause)
+ if (cheapest_path->parent)
+ {
+ path_rows = cheapest_path->parent->rows;
+ path_width = cheapest_path->parent->width;
+ }
+ else
{
- bool can_hash;
- bool can_sort;
+ path_rows = 1; /* assume non-set result */
+ path_width = 100; /* arbitrary */
+ }
+ if (parse->groupClause)
+ {
/*
- * Executor doesn't support hashed aggregation with DISTINCT
- * aggregates. (Doing so would imply storing *all* the input
- * values in the hash table, which seems like a certain loser.)
+ * If grouping, decide whether to use sorted or hashed grouping.
*/
- can_hash = (agg_counts.numDistinctAggs == 0 &&
- grouping_is_hashable(parse->groupClause));
- can_sort = grouping_is_sortable(parse->groupClause);
- if (can_hash && can_sort)
- {
- /* we have a meaningful choice to make ... */
- use_hashed_grouping =
- choose_hashed_grouping(root,
- tuple_fraction, limit_tuples,
- cheapest_path, sorted_path,
- dNumGroups, &agg_counts);
- }
- else if (can_hash)
- use_hashed_grouping = true;
- else if (can_sort)
- use_hashed_grouping = false;
- else
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("could not implement GROUP BY"),
- errdetail("Some of the datatypes only support hashing, while others only support sorting.")));
-
+ use_hashed_grouping =
+ choose_hashed_grouping(root,
+ tuple_fraction, limit_tuples,
+ path_rows, path_width,
+ cheapest_path, sorted_path,
+ dNumGroups, &agg_costs);
/* Also convert # groups to long int --- but 'ware overflow! */
numGroups = (long) Min(dNumGroups, (double) LONG_MAX);
}
+ else if (parse->distinctClause && sorted_path &&
+ !root->hasHavingQual && !parse->hasAggs && !activeWindows)
+ {
+ /*
+ * We'll reach the DISTINCT stage without any intermediate
+ * processing, so figure out whether we will want to hash or not
+ * so we can choose whether to use cheapest or sorted path.
+ */
+ use_hashed_distinct =
+ choose_hashed_distinct(root,
+ tuple_fraction, limit_tuples,
+ path_rows, path_width,
+ cheapest_path->startup_cost,
+ cheapest_path->total_cost,
+ sorted_path->startup_cost,
+ sorted_path->total_cost,
+ sorted_path->pathkeys,
+ dNumGroups);
+ tested_hashed_distinct = true;
+ }
/*
* Select the best path. If we are doing hashed grouping, we will
* always read all the input tuples, so use the cheapest-total path.
* Otherwise, trust query_planner's decision about which to use.
*/
- if (use_hashed_grouping || !sorted_path)
+ if (use_hashed_grouping || use_hashed_distinct || !sorted_path)
best_path = cheapest_path;
else
best_path = sorted_path;
*/
result_plan = optimize_minmax_aggregates(root,
tlist,
+ &agg_costs,
best_path);
if (result_plan != NULL)
{
* Normal case --- create a plan according to query_planner's
* results.
*/
- bool need_sort_for_grouping = false;
+ bool need_sort_for_grouping = false;
result_plan = create_plan(root, best_path);
current_pathkeys = best_path->pathkeys;
/* Detect if we'll need an explicit sort for grouping */
if (parse->groupClause && !use_hashed_grouping &&
- !pathkeys_contained_in(root->group_pathkeys, current_pathkeys))
+ !pathkeys_contained_in(root->group_pathkeys, current_pathkeys))
{
need_sort_for_grouping = true;
+
/*
- * Always override query_planner's tlist, so that we don't
- * sort useless data from a "physical" tlist.
+ * Always override create_plan's tlist, so that we don't sort
+ * useless data from a "physical" tlist.
*/
need_tlist_eval = true;
}
/*
- * create_plan() returns a plan with just a "flat" tlist of
- * required Vars. Usually we need to insert the sub_tlist as the
- * tlist of the top plan node. However, we can skip that if we
- * determined that whatever query_planner chose to return will be
- * good enough.
+ * create_plan returns a plan with just a "flat" tlist of required
+ * Vars. Usually we need to insert the sub_tlist as the tlist of
+ * the top plan node. However, we can skip that if we determined
+ * that whatever create_plan chose to return will be good enough.
*/
if (need_tlist_eval)
{
/*
* Also, account for the cost of evaluation of the sub_tlist.
- *
- * Up to now, we have only been dealing with "flat" tlists,
- * containing just Vars. So their evaluation cost is zero
- * according to the model used by cost_qual_eval() (or if you
- * prefer, the cost is factored into cpu_tuple_cost). Thus we
- * can avoid accounting for tlist cost throughout
- * query_planner() and subroutines. But now we've inserted a
- * tlist that might contain actual operators, sub-selects, etc
- * --- so we'd better account for its cost.
- *
- * Below this point, any tlist eval cost for added-on nodes
- * should be accounted for as we create those nodes.
- * Presently, of the node types we can add on, only Agg and
- * Group project new tlists (the rest just copy their input
- * tuples) --- so make_agg() and make_group() are responsible
- * for computing the added cost.
+ * See comments for add_tlist_costs_to_plan() for more info.
*/
- cost_qual_eval(&tlist_cost, sub_tlist, root);
- result_plan->startup_cost += tlist_cost.startup;
- result_plan->total_cost += tlist_cost.startup +
- tlist_cost.per_tuple * result_plan->plan_rows;
+ add_tlist_costs_to_plan(root, result_plan, sub_tlist);
}
else
{
/*
- * Since we're using query_planner's tlist and not the one
+ * Since we're using create_plan's tlist and not the one
* make_subplanTargetList calculated, we have to refigure any
* grouping-column indexes make_subplanTargetList computed.
*/
tlist,
(List *) parse->havingQual,
AGG_HASHED,
+ &agg_costs,
numGroupCols,
groupColIdx,
extract_grouping_ops(parse->groupClause),
numGroups,
- agg_counts.numAggs,
result_plan);
/* Hashed aggregation produces randomly-ordered results */
current_pathkeys = NIL;
tlist,
(List *) parse->havingQual,
aggstrategy,
+ &agg_costs,
numGroupCols,
groupColIdx,
extract_grouping_ops(parse->groupClause),
numGroups,
- agg_counts.numAggs,
result_plan);
}
else if (parse->groupClause)
NULL);
}
} /* end of non-minmax-aggregate case */
+
+ /*
+ * Since each window function could require a different sort order, we
+ * stack up a WindowAgg node for each window, with sort steps between
+ * them as needed.
+ */
+ if (activeWindows)
+ {
+ List *window_tlist;
+ ListCell *l;
+
+ /*
+ * If the top-level plan node is one that cannot do expression
+ * evaluation, we must insert a Result node to project the desired
+ * tlist. (In some cases this might not really be required, but
+ * it's not worth trying to avoid it.) Note that on second and
+ * subsequent passes through the following loop, the top-level
+ * node will be a WindowAgg which we know can project; so we only
+ * need to check once.
+ */
+ if (!is_projection_capable_plan(result_plan))
+ {
+ result_plan = (Plan *) make_result(root,
+ NIL,
+ NULL,
+ result_plan);
+ }
+
+ /*
+ * The "base" targetlist for all steps of the windowing process is
+ * a flat tlist of all Vars and Aggs needed in the result. (In
+ * some cases we wouldn't need to propagate all of these all the
+ * way to the top, since they might only be needed as inputs to
+ * WindowFuncs. It's probably not worth trying to optimize that
+ * though.) We also need any volatile sort expressions, because
+ * make_sort_from_pathkeys won't add those on its own, and anyway
+ * we want them evaluated only once at the bottom of the stack. As
+ * we climb up the stack, we add outputs for the WindowFuncs
+ * computed at each level. Also, each input tlist has to present
+ * all the columns needed to sort the data for the next WindowAgg
+ * step. That's handled internally by make_sort_from_pathkeys,
+ * but we need the copyObject steps here to ensure that each plan
+ * node has a separately modifiable tlist.
+ *
+ * Note: it's essential here to use PVC_INCLUDE_AGGREGATES so that
+ * Vars mentioned only in aggregate expressions aren't pulled out
+ * as separate targetlist entries. Otherwise we could be putting
+ * ungrouped Vars directly into an Agg node's tlist, resulting in
+ * undefined behavior.
+ */
+ window_tlist = flatten_tlist(tlist,
+ PVC_INCLUDE_AGGREGATES,
+ PVC_INCLUDE_PLACEHOLDERS);
+ window_tlist = add_volatile_sort_exprs(window_tlist, tlist,
+ activeWindows);
+ result_plan->targetlist = (List *) copyObject(window_tlist);
+
+ foreach(l, activeWindows)
+ {
+ WindowClause *wc = (WindowClause *) lfirst(l);
+ List *window_pathkeys;
+ int partNumCols;
+ AttrNumber *partColIdx;
+ Oid *partOperators;
+ int ordNumCols;
+ AttrNumber *ordColIdx;
+ Oid *ordOperators;
+
+ window_pathkeys = make_pathkeys_for_window(root,
+ wc,
+ tlist,
+ true);
+
+ /*
+ * This is a bit tricky: we build a sort node even if we don't
+ * really have to sort. Even when no explicit sort is needed,
+ * we need to have suitable resjunk items added to the input
+ * plan's tlist for any partitioning or ordering columns that
+ * aren't plain Vars. Furthermore, this way we can use
+ * existing infrastructure to identify which input columns are
+ * the interesting ones.
+ */
+ if (window_pathkeys)
+ {
+ Sort *sort_plan;
+
+ sort_plan = make_sort_from_pathkeys(root,
+ result_plan,
+ window_pathkeys,
+ -1.0);
+ if (!pathkeys_contained_in(window_pathkeys,
+ current_pathkeys))
+ {
+ /* we do indeed need to sort */
+ result_plan = (Plan *) sort_plan;
+ current_pathkeys = window_pathkeys;
+ }
+ /* In either case, extract the per-column information */
+ get_column_info_for_window(root, wc, tlist,
+ sort_plan->numCols,
+ sort_plan->sortColIdx,
+ &partNumCols,
+ &partColIdx,
+ &partOperators,
+ &ordNumCols,
+ &ordColIdx,
+ &ordOperators);
+ }
+ else
+ {
+ /* empty window specification, nothing to sort */
+ partNumCols = 0;
+ partColIdx = NULL;
+ partOperators = NULL;
+ ordNumCols = 0;
+ ordColIdx = NULL;
+ ordOperators = NULL;
+ }
+
+ if (lnext(l))
+ {
+ /* Add the current WindowFuncs to the running tlist */
+ window_tlist = add_to_flat_tlist(window_tlist,
+ wflists->windowFuncs[wc->winref]);
+ }
+ else
+ {
+ /* Install the original tlist in the topmost WindowAgg */
+ window_tlist = tlist;
+ }
+
+ /* ... and make the WindowAgg plan node */
+ result_plan = (Plan *)
+ make_windowagg(root,
+ (List *) copyObject(window_tlist),
+ wflists->windowFuncs[wc->winref],
+ wc->winref,
+ partNumCols,
+ partColIdx,
+ partOperators,
+ ordNumCols,
+ ordColIdx,
+ ordOperators,
+ wc->frameOptions,
+ wc->startOffset,
+ wc->endOffset,
+ result_plan);
+ }
+ }
} /* end of if (setOperations) */
/*
*/
if (parse->distinctClause)
{
- double dNumDistinctRows;
- long numDistinctRows;
- bool use_hashed_distinct;
- bool can_sort;
- bool can_hash;
+ double dNumDistinctRows;
+ long numDistinctRows;
/*
* If there was grouping or aggregation, use the current number of
/* Also convert to long int --- but 'ware overflow! */
numDistinctRows = (long) Min(dNumDistinctRows, (double) LONG_MAX);
- /*
- * If we have a sortable DISTINCT ON clause, we always use sorting.
- * This enforces the expected behavior of DISTINCT ON.
- */
- can_sort = grouping_is_sortable(parse->distinctClause);
- if (can_sort && parse->hasDistinctOn)
- use_hashed_distinct = false;
- else
+ /* Choose implementation method if we didn't already */
+ if (!tested_hashed_distinct)
{
- can_hash = grouping_is_hashable(parse->distinctClause);
- if (can_hash && can_sort)
- {
- /* we have a meaningful choice to make ... */
- use_hashed_distinct =
- choose_hashed_distinct(root,
- result_plan, current_pathkeys,
- tuple_fraction, limit_tuples,
- dNumDistinctRows);
- }
- else if (can_hash)
- use_hashed_distinct = true;
- else if (can_sort)
- use_hashed_distinct = false;
- else
- {
- ereport(ERROR,
- (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
- errmsg("could not implement DISTINCT"),
- errdetail("Some of the datatypes only support hashing, while others only support sorting.")));
- use_hashed_distinct = false; /* keep compiler quiet */
- }
+ /*
+ * At this point, either hashed or sorted grouping will have to
+ * work from result_plan, so we pass that as both "cheapest" and
+ * "sorted".
+ */
+ use_hashed_distinct =
+ choose_hashed_distinct(root,
+ tuple_fraction, limit_tuples,
+ result_plan->plan_rows,
+ result_plan->plan_width,
+ result_plan->startup_cost,
+ result_plan->total_cost,
+ result_plan->startup_cost,
+ result_plan->total_cost,
+ current_pathkeys,
+ dNumDistinctRows);
}
if (use_hashed_distinct)
result_plan->targetlist,
NIL,
AGG_HASHED,
- list_length(parse->distinctClause),
- extract_grouping_cols(parse->distinctClause,
- result_plan->targetlist),
- extract_grouping_ops(parse->distinctClause),
+ NULL,
+ list_length(parse->distinctClause),
+ extract_grouping_cols(parse->distinctClause,
+ result_plan->targetlist),
+ extract_grouping_ops(parse->distinctClause),
numDistinctRows,
- 0,
result_plan);
/* Hashed aggregation produces randomly-ordered results */
current_pathkeys = NIL;
* rigorous of DISTINCT and ORDER BY, to avoid a second sort
* below. However, for regular DISTINCT, don't sort now if we
* don't have to --- sorting afterwards will likely be cheaper,
- * and also has the possibility of optimizing via LIMIT. But
- * for DISTINCT ON, we *must* force the final sort now, else
- * it won't have the desired behavior.
+ * and also has the possibility of optimizing via LIMIT. But for
+ * DISTINCT ON, we *must* force the final sort now, else it won't
+ * have the desired behavior.
*/
- List *needed_pathkeys;
+ List *needed_pathkeys;
if (parse->hasDistinctOn &&
list_length(root->distinct_pathkeys) <
result_plan = (Plan *) make_sort_from_pathkeys(root,
result_plan,
- current_pathkeys,
+ current_pathkeys,
-1.0);
}
{
result_plan = (Plan *) make_sort_from_pathkeys(root,
result_plan,
- root->sort_pathkeys,
+ root->sort_pathkeys,
limit_tuples);
current_pathkeys = root->sort_pathkeys;
}
}
+ /*
+ * If there is a FOR UPDATE/SHARE clause, add the LockRows node. (Note: we
+ * intentionally test parse->rowMarks not root->rowMarks here. If there
+ * are only non-locking rowmarks, they should be handled by the
+ * ModifyTable node instead.)
+ */
+ if (parse->rowMarks)
+ {
+ result_plan = (Plan *) make_lockrows(result_plan,
+ root->rowMarks,
+ SS_assign_special_param(root));
+
+ /*
+ * The result can no longer be assumed sorted, since locking might
+ * cause the sort key columns to be replaced with new values.
+ */
+ current_pathkeys = NIL;
+ }
+
/*
* Finally, if there is a LIMIT/OFFSET clause, add the LIMIT node.
*/
count_est);
}
- /*
- * Deal with the RETURNING clause if any. It's convenient to pass the
- * returningList through setrefs.c now rather than at top level (if we
- * waited, handling inherited UPDATE/DELETE would be much harder).
- */
- if (parse->returningList)
- {
- List *rlist;
-
- Assert(parse->resultRelation);
- rlist = set_returning_clause_references(root->glob,
- parse->returningList,
- result_plan,
- parse->resultRelation);
- root->returningLists = list_make1(rlist);
- }
- else
- root->returningLists = NIL;
-
- /* Compute result-relations list if needed */
- if (parse->resultRelation)
- root->resultRelations = list_make1_int(parse->resultRelation);
- else
- root->resultRelations = NIL;
-
/*
* Return the actual output ordering in query_pathkeys for possible use by
* an outer query level.
return result_plan;
}
+/*
+ * add_tlist_costs_to_plan
+ *
+ * Estimate the execution costs associated with evaluating the targetlist
+ * expressions, and add them to the cost estimates for the Plan node.
+ *
+ * If the tlist contains set-returning functions, also inflate the Plan's cost
+ * and plan_rows estimates accordingly. (Hence, this must be called *after*
+ * any logic that uses plan_rows to, eg, estimate qual evaluation costs.)
+ *
+ * Note: during initial stages of planning, we mostly consider plan nodes with
+ * "flat" tlists, containing just Vars. So their evaluation cost is zero
+ * according to the model used by cost_qual_eval() (or if you prefer, the cost
+ * is factored into cpu_tuple_cost). Thus we can avoid accounting for tlist
+ * cost throughout query_planner() and subroutines. But once we apply a
+ * tlist that might contain actual operators, sub-selects, etc, we'd better
+ * account for its cost. Any set-returning functions in the tlist must also
+ * affect the estimated rowcount.
+ *
+ * Once grouping_planner() has applied a general tlist to the topmost
+ * scan/join plan node, any tlist eval cost for added-on nodes should be
+ * accounted for as we create those nodes. Presently, of the node types we
+ * can add on later, only Agg, WindowAgg, and Group project new tlists (the
+ * rest just copy their input tuples) --- so make_agg(), make_windowagg() and
+ * make_group() are responsible for calling this function to account for their
+ * tlist costs.
+ */
+void
+add_tlist_costs_to_plan(PlannerInfo *root, Plan *plan, List *tlist)
+{
+ QualCost tlist_cost;
+ double tlist_rows;
+
+ cost_qual_eval(&tlist_cost, tlist, root);
+ plan->startup_cost += tlist_cost.startup;
+ plan->total_cost += tlist_cost.startup +
+ tlist_cost.per_tuple * plan->plan_rows;
+
+ tlist_rows = tlist_returns_set_rows(tlist);
+ if (tlist_rows > 1)
+ {
+ /*
+ * We assume that execution costs of the tlist proper were all
+ * accounted for by cost_qual_eval. However, it still seems
+ * appropriate to charge something more for the executor's general
+ * costs of processing the added tuples. The cost is probably less
+ * than cpu_tuple_cost, though, so we arbitrarily use half of that.
+ */
+ plan->total_cost += plan->plan_rows * (tlist_rows - 1) *
+ cpu_tuple_cost / 2;
+
+ plan->plan_rows *= tlist_rows;
+ }
+}
+
/*
* Detect whether a plan node is a "dummy" plan created when a relation
* is deemed not to need scanning due to constraint exclusion.
*
* Currently, such dummy plans are Result nodes with constant FALSE
- * filter quals.
+ * filter quals (see set_dummy_rel_pathlist and create_append_plan).
+ *
+ * XXX this probably ought to be somewhere else, but not clear where.
*/
-static bool
+bool
is_dummy_plan(Plan *plan)
{
if (IsA(plan, Result))
}
/*
- * preprocess_limit - do pre-estimation for LIMIT and/or OFFSET clauses
- *
- * We try to estimate the values of the LIMIT/OFFSET clauses, and pass the
- * results back in *count_est and *offset_est. These variables are set to
- * 0 if the corresponding clause is not present, and -1 if it's present
- * but we couldn't estimate the value for it. (The "0" convention is OK
- * for OFFSET but a little bit bogus for LIMIT: effectively we estimate
- * LIMIT 0 as though it were LIMIT 1. But this is in line with the planner's
- * usual practice of never estimating less than one row.) These values will
- * be passed to make_limit, which see if you change this code.
+ * Create a bitmapset of the RT indexes of live base relations
*
- * The return value is the suitably adjusted tuple_fraction to use for
- * planning the query. This adjustment is not overridable, since it reflects
- * plan actions that grouping_planner() will certainly take, not assumptions
+ * Helper for preprocess_rowmarks ... at this point in the proceedings,
+ * the only good way to distinguish baserels from appendrel children
+ * is to see what is in the join tree.
+ */
+static Bitmapset *
+get_base_rel_indexes(Node *jtnode)
+{
+ Bitmapset *result;
+
+ if (jtnode == NULL)
+ return NULL;
+ if (IsA(jtnode, RangeTblRef))
+ {
+ int varno = ((RangeTblRef *) jtnode)->rtindex;
+
+ result = bms_make_singleton(varno);
+ }
+ else if (IsA(jtnode, FromExpr))
+ {
+ FromExpr *f = (FromExpr *) jtnode;
+ ListCell *l;
+
+ result = NULL;
+ foreach(l, f->fromlist)
+ result = bms_join(result,
+ get_base_rel_indexes(lfirst(l)));
+ }
+ else if (IsA(jtnode, JoinExpr))
+ {
+ JoinExpr *j = (JoinExpr *) jtnode;
+
+ result = bms_join(get_base_rel_indexes(j->larg),
+ get_base_rel_indexes(j->rarg));
+ }
+ else
+ {
+ elog(ERROR, "unrecognized node type: %d",
+ (int) nodeTag(jtnode));
+ result = NULL; /* keep compiler quiet */
+ }
+ return result;
+}
+
+/*
+ * preprocess_rowmarks - set up PlanRowMarks if needed
+ */
+static void
+preprocess_rowmarks(PlannerInfo *root)
+{
+ Query *parse = root->parse;
+ Bitmapset *rels;
+ List *prowmarks;
+ ListCell *l;
+ int i;
+
+ if (parse->rowMarks)
+ {
+ /*
+ * We've got trouble if FOR UPDATE/SHARE appears inside grouping,
+ * since grouping renders a reference to individual tuple CTIDs
+ * invalid. This is also checked at parse time, but that's
+ * insufficient because of rule substitution, query pullup, etc.
+ */
+ CheckSelectLocking(parse);
+ }
+ else
+ {
+ /*
+ * We only need rowmarks for UPDATE, DELETE, or FOR UPDATE/SHARE.
+ */
+ if (parse->commandType != CMD_UPDATE &&
+ parse->commandType != CMD_DELETE)
+ return;
+ }
+
+ /*
+ * We need to have rowmarks for all base relations except the target. We
+ * make a bitmapset of all base rels and then remove the items we don't
+ * need or have FOR UPDATE/SHARE marks for.
+ */
+ rels = get_base_rel_indexes((Node *) parse->jointree);
+ if (parse->resultRelation)
+ rels = bms_del_member(rels, parse->resultRelation);
+
+ /*
+ * Convert RowMarkClauses to PlanRowMark representation.
+ */
+ prowmarks = NIL;
+ foreach(l, parse->rowMarks)
+ {
+ RowMarkClause *rc = (RowMarkClause *) lfirst(l);
+ RangeTblEntry *rte = rt_fetch(rc->rti, parse->rtable);
+ PlanRowMark *newrc;
+
+ /*
+ * Currently, it is syntactically impossible to have FOR UPDATE
+ * applied to an update/delete target rel. If that ever becomes
+ * possible, we should drop the target from the PlanRowMark list.
+ */
+ Assert(rc->rti != parse->resultRelation);
+
+ /*
+ * Ignore RowMarkClauses for subqueries; they aren't real tables and
+ * can't support true locking. Subqueries that got flattened into the
+ * main query should be ignored completely. Any that didn't will get
+ * ROW_MARK_COPY items in the next loop.
+ */
+ if (rte->rtekind != RTE_RELATION)
+ continue;
+
+ rels = bms_del_member(rels, rc->rti);
+
+ newrc = makeNode(PlanRowMark);
+ newrc->rti = newrc->prti = rc->rti;
+ newrc->rowmarkId = ++(root->glob->lastRowMarkId);
+ if (rc->forUpdate)
+ newrc->markType = ROW_MARK_EXCLUSIVE;
+ else
+ newrc->markType = ROW_MARK_SHARE;
+ newrc->noWait = rc->noWait;
+ newrc->isParent = false;
+
+ prowmarks = lappend(prowmarks, newrc);
+ }
+
+ /*
+ * Now, add rowmarks for any non-target, non-locked base relations.
+ */
+ i = 0;
+ foreach(l, parse->rtable)
+ {
+ RangeTblEntry *rte = (RangeTblEntry *) lfirst(l);
+ PlanRowMark *newrc;
+
+ i++;
+ if (!bms_is_member(i, rels))
+ continue;
+
+ newrc = makeNode(PlanRowMark);
+ newrc->rti = newrc->prti = i;
+ newrc->rowmarkId = ++(root->glob->lastRowMarkId);
+ /* real tables support REFERENCE, anything else needs COPY */
+ if (rte->rtekind == RTE_RELATION &&
+ rte->relkind != RELKIND_FOREIGN_TABLE)
+ newrc->markType = ROW_MARK_REFERENCE;
+ else
+ newrc->markType = ROW_MARK_COPY;
+ newrc->noWait = false; /* doesn't matter */
+ newrc->isParent = false;
+
+ prowmarks = lappend(prowmarks, newrc);
+ }
+
+ root->rowMarks = prowmarks;
+}
+
+/*
+ * preprocess_limit - do pre-estimation for LIMIT and/or OFFSET clauses
+ *
+ * We try to estimate the values of the LIMIT/OFFSET clauses, and pass the
+ * results back in *count_est and *offset_est. These variables are set to
+ * 0 if the corresponding clause is not present, and -1 if it's present
+ * but we couldn't estimate the value for it. (The "0" convention is OK
+ * for OFFSET but a little bit bogus for LIMIT: effectively we estimate
+ * LIMIT 0 as though it were LIMIT 1. But this is in line with the planner's
+ * usual practice of never estimating less than one row.) These values will
+ * be passed to make_limit, which see if you change this code.
+ *
+ * The return value is the suitably adjusted tuple_fraction to use for
+ * planning the query. This adjustment is not overridable, since it reflects
+ * plan actions that grouping_planner() will certainly take, not assumptions
* about context.
*/
static double
return;
/*
- * Add any remaining GROUP BY items to the new list, but only if we
- * were able to make a complete match. In other words, we only
- * rearrange the GROUP BY list if the result is that one list is a
- * prefix of the other --- otherwise there's no possibility of a
- * common sort. Also, give up if there are any non-sortable GROUP BY
- * items, since then there's no hope anyway.
+ * Add any remaining GROUP BY items to the new list, but only if we were
+ * able to make a complete match. In other words, we only rearrange the
+ * GROUP BY list if the result is that one list is a prefix of the other
+ * --- otherwise there's no possibility of a common sort. Also, give up
+ * if there are any non-sortable GROUP BY items, since then there's no
+ * hope anyway.
*/
foreach(gl, parse->groupClause)
{
/*
* choose_hashed_grouping - should we use hashed grouping?
*
- * Note: this is only applied when both alternatives are actually feasible.
+ * Returns TRUE to select hashing, FALSE to select sorting.
*/
static bool
choose_hashed_grouping(PlannerInfo *root,
double tuple_fraction, double limit_tuples,
+ double path_rows, int path_width,
Path *cheapest_path, Path *sorted_path,
- double dNumGroups, AggClauseCounts *agg_counts)
+ double dNumGroups, AggClauseCosts *agg_costs)
{
- int numGroupCols = list_length(root->parse->groupClause);
- double cheapest_path_rows;
- int cheapest_path_width;
+ Query *parse = root->parse;
+ int numGroupCols = list_length(parse->groupClause);
+ bool can_hash;
+ bool can_sort;
Size hashentrysize;
List *target_pathkeys;
List *current_pathkeys;
Path hashed_p;
Path sorted_p;
+ /*
+ * Executor doesn't support hashed aggregation with DISTINCT or ORDER BY
+ * aggregates. (Doing so would imply storing *all* the input values in
+ * the hash table, and/or running many sorts in parallel, either of which
+ * seems like a certain loser.)
+ */
+ can_hash = (agg_costs->numOrderedAggs == 0 &&
+ grouping_is_hashable(parse->groupClause));
+ can_sort = grouping_is_sortable(parse->groupClause);
+
+ /* Quick out if only one choice is workable */
+ if (!(can_hash && can_sort))
+ {
+ if (can_hash)
+ return true;
+ else if (can_sort)
+ return false;
+ else
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("could not implement GROUP BY"),
+ errdetail("Some of the datatypes only support hashing, while others only support sorting.")));
+ }
+
/* Prefer sorting when enable_hashagg is off */
if (!enable_hashagg)
return false;
/*
* Don't do it if it doesn't look like the hashtable will fit into
* work_mem.
- *
- * Beware here of the possibility that cheapest_path->parent is NULL. This
- * could happen if user does something silly like SELECT 'foo' GROUP BY 1;
*/
- if (cheapest_path->parent)
- {
- cheapest_path_rows = cheapest_path->parent->rows;
- cheapest_path_width = cheapest_path->parent->width;
- }
- else
- {
- cheapest_path_rows = 1; /* assume non-set result */
- cheapest_path_width = 100; /* arbitrary */
- }
/* Estimate per-hash-entry space at tuple width... */
- hashentrysize = MAXALIGN(cheapest_path_width) + MAXALIGN(sizeof(MinimalTupleData));
+ hashentrysize = MAXALIGN(path_width) + MAXALIGN(sizeof(MinimalTupleData));
/* plus space for pass-by-ref transition values... */
- hashentrysize += agg_counts->transitionSpace;
+ hashentrysize += agg_costs->transitionSpace;
/* plus the per-hash-entry overhead */
- hashentrysize += hash_agg_entry_size(agg_counts->numAggs);
+ hashentrysize += hash_agg_entry_size(agg_costs->numAggs);
if (hashentrysize * dNumGroups > work_mem * 1024L)
return false;
/*
* When we have both GROUP BY and DISTINCT, use the more-rigorous of
- * DISTINCT and ORDER BY as the assumed required output sort order.
- * This is an oversimplification because the DISTINCT might get
- * implemented via hashing, but it's not clear that the case is common
- * enough (or that our estimates are good enough) to justify trying to
- * solve it exactly.
+ * DISTINCT and ORDER BY as the assumed required output sort order. This
+ * is an oversimplification because the DISTINCT might get implemented via
+ * hashing, but it's not clear that the case is common enough (or that our
+ * estimates are good enough) to justify trying to solve it exactly.
*/
if (list_length(root->distinct_pathkeys) >
list_length(root->sort_pathkeys))
* These path variables are dummies that just hold cost fields; we don't
* make actual Paths for these steps.
*/
- cost_agg(&hashed_p, root, AGG_HASHED, agg_counts->numAggs,
+ cost_agg(&hashed_p, root, AGG_HASHED, agg_costs,
numGroupCols, dNumGroups,
cheapest_path->startup_cost, cheapest_path->total_cost,
- cheapest_path_rows);
+ path_rows);
/* Result of hashed agg is always unsorted */
if (target_pathkeys)
cost_sort(&hashed_p, root, target_pathkeys, hashed_p.total_cost,
- dNumGroups, cheapest_path_width, limit_tuples);
+ dNumGroups, path_width,
+ 0.0, work_mem, limit_tuples);
if (sorted_path)
{
if (!pathkeys_contained_in(root->group_pathkeys, current_pathkeys))
{
cost_sort(&sorted_p, root, root->group_pathkeys, sorted_p.total_cost,
- cheapest_path_rows, cheapest_path_width, -1.0);
+ path_rows, path_width,
+ 0.0, work_mem, -1.0);
current_pathkeys = root->group_pathkeys;
}
- if (root->parse->hasAggs)
- cost_agg(&sorted_p, root, AGG_SORTED, agg_counts->numAggs,
+ if (parse->hasAggs)
+ cost_agg(&sorted_p, root, AGG_SORTED, agg_costs,
numGroupCols, dNumGroups,
sorted_p.startup_cost, sorted_p.total_cost,
- cheapest_path_rows);
+ path_rows);
else
cost_group(&sorted_p, root, numGroupCols, dNumGroups,
sorted_p.startup_cost, sorted_p.total_cost,
- cheapest_path_rows);
+ path_rows);
/* The Agg or Group node will preserve ordering */
if (target_pathkeys &&
!pathkeys_contained_in(target_pathkeys, current_pathkeys))
cost_sort(&sorted_p, root, target_pathkeys, sorted_p.total_cost,
- dNumGroups, cheapest_path_width, limit_tuples);
+ dNumGroups, path_width,
+ 0.0, work_mem, limit_tuples);
/*
* Now make the decision using the top-level tuple fraction. First we
*
* This is fairly similar to choose_hashed_grouping, but there are enough
* differences that it doesn't seem worth trying to unify the two functions.
+ * (One difference is that we sometimes apply this after forming a Plan,
+ * so the input alternatives can't be represented as Paths --- instead we
+ * pass in the costs as individual variables.)
*
* But note that making the two choices independently is a bit bogus in
- * itself. If the two could be combined into a single choice operation
+ * itself. If the two could be combined into a single choice operation
* it'd probably be better, but that seems far too unwieldy to be practical,
* especially considering that the combination of GROUP BY and DISTINCT
* isn't very common in real queries. By separating them, we are giving
* extra preference to using a sorting implementation when a common sort key
* is available ... and that's not necessarily wrong anyway.
*
- * Note: this is only applied when both alternatives are actually feasible.
+ * Returns TRUE to select hashing, FALSE to select sorting.
*/
static bool
choose_hashed_distinct(PlannerInfo *root,
- Plan *input_plan, List *input_pathkeys,
double tuple_fraction, double limit_tuples,
+ double path_rows, int path_width,
+ Cost cheapest_startup_cost, Cost cheapest_total_cost,
+ Cost sorted_startup_cost, Cost sorted_total_cost,
+ List *sorted_pathkeys,
double dNumDistinctRows)
{
- int numDistinctCols = list_length(root->parse->distinctClause);
+ Query *parse = root->parse;
+ int numDistinctCols = list_length(parse->distinctClause);
+ bool can_sort;
+ bool can_hash;
Size hashentrysize;
List *current_pathkeys;
List *needed_pathkeys;
Path hashed_p;
Path sorted_p;
+ /*
+ * If we have a sortable DISTINCT ON clause, we always use sorting. This
+ * enforces the expected behavior of DISTINCT ON.
+ */
+ can_sort = grouping_is_sortable(parse->distinctClause);
+ if (can_sort && parse->hasDistinctOn)
+ return false;
+
+ can_hash = grouping_is_hashable(parse->distinctClause);
+
+ /* Quick out if only one choice is workable */
+ if (!(can_hash && can_sort))
+ {
+ if (can_hash)
+ return true;
+ else if (can_sort)
+ return false;
+ else
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("could not implement DISTINCT"),
+ errdetail("Some of the datatypes only support hashing, while others only support sorting.")));
+ }
+
/* Prefer sorting when enable_hashagg is off */
if (!enable_hashagg)
return false;
* Don't do it if it doesn't look like the hashtable will fit into
* work_mem.
*/
- hashentrysize = MAXALIGN(input_plan->plan_width) + MAXALIGN(sizeof(MinimalTupleData));
+ hashentrysize = MAXALIGN(path_width) + MAXALIGN(sizeof(MinimalTupleData));
if (hashentrysize * dNumDistinctRows > work_mem * 1024L)
return false;
* output won't be sorted may be a loss; so we need to do an actual cost
* comparison.
*
- * We need to consider input_plan + hashagg [+ final sort] versus
- * input_plan [+ sort] + group [+ final sort] where brackets indicate
- * a step that may not be needed.
+ * We need to consider cheapest_path + hashagg [+ final sort] versus
+ * sorted_path [+ sort] + group [+ final sort] where brackets indicate a
+ * step that may not be needed.
*
* These path variables are dummies that just hold cost fields; we don't
* make actual Paths for these steps.
*/
- cost_agg(&hashed_p, root, AGG_HASHED, 0,
+ cost_agg(&hashed_p, root, AGG_HASHED, NULL,
numDistinctCols, dNumDistinctRows,
- input_plan->startup_cost, input_plan->total_cost,
- input_plan->plan_rows);
+ cheapest_startup_cost, cheapest_total_cost,
+ path_rows);
+
/*
- * Result of hashed agg is always unsorted, so if ORDER BY is present
- * we need to charge for the final sort.
+ * Result of hashed agg is always unsorted, so if ORDER BY is present we
+ * need to charge for the final sort.
*/
- if (root->parse->sortClause)
+ if (parse->sortClause)
cost_sort(&hashed_p, root, root->sort_pathkeys, hashed_p.total_cost,
- dNumDistinctRows, input_plan->plan_width, limit_tuples);
+ dNumDistinctRows, path_width,
+ 0.0, work_mem, limit_tuples);
/*
- * Now for the GROUP case. See comments in grouping_planner about the
+ * Now for the GROUP case. See comments in grouping_planner about the
* sorting choices here --- this code should match that code.
*/
- sorted_p.startup_cost = input_plan->startup_cost;
- sorted_p.total_cost = input_plan->total_cost;
- current_pathkeys = input_pathkeys;
- if (root->parse->hasDistinctOn &&
+ sorted_p.startup_cost = sorted_startup_cost;
+ sorted_p.total_cost = sorted_total_cost;
+ current_pathkeys = sorted_pathkeys;
+ if (parse->hasDistinctOn &&
list_length(root->distinct_pathkeys) <
list_length(root->sort_pathkeys))
needed_pathkeys = root->sort_pathkeys;
else
current_pathkeys = root->sort_pathkeys;
cost_sort(&sorted_p, root, current_pathkeys, sorted_p.total_cost,
- input_plan->plan_rows, input_plan->plan_width, -1.0);
+ path_rows, path_width,
+ 0.0, work_mem, -1.0);
}
cost_group(&sorted_p, root, numDistinctCols, dNumDistinctRows,
sorted_p.startup_cost, sorted_p.total_cost,
- input_plan->plan_rows);
- if (root->parse->sortClause &&
+ path_rows);
+ if (parse->sortClause &&
!pathkeys_contained_in(root->sort_pathkeys, current_pathkeys))
cost_sort(&sorted_p, root, root->sort_pathkeys, sorted_p.total_cost,
- dNumDistinctRows, input_plan->plan_width, limit_tuples);
+ dNumDistinctRows, path_width,
+ 0.0, work_mem, limit_tuples);
/*
* Now make the decision using the top-level tuple fraction. First we
return false;
}
-/*---------------
+/*
* make_subplanTargetList
* Generate appropriate target list when grouping is required.
*
- * When grouping_planner inserts Aggregate, Group, or Result plan nodes
- * above the result of query_planner, we typically want to pass a different
- * target list to query_planner than the outer plan nodes should have.
- * This routine generates the correct target list for the subplan.
+ * When grouping_planner inserts grouping or aggregation plan nodes
+ * above the scan/join plan constructed by query_planner+create_plan,
+ * we typically want the scan/join plan to emit a different target list
+ * than the outer plan nodes should have. This routine generates the
+ * correct target list for the scan/join subplan.
*
* The initial target list passed from the parser already contains entries
* for all ORDER BY and GROUP BY expressions, but it will not have entries
* For example, given a query like
* SELECT a+b,SUM(c+d) FROM table GROUP BY a+b;
* we want to pass this targetlist to the subplan:
- * a,b,c,d,a+b
+ * a+b,c,d
* where the a+b target will be used by the Sort/Group steps, and the
- * other targets will be used for computing the final results. (In the
- * above example we could theoretically suppress the a and b targets and
- * pass down only c,d,a+b, but it's not really worth the trouble to
- * eliminate simple var references from the subplan. We will avoid doing
- * the extra computation to recompute a+b at the outer level; see
- * fix_upper_expr() in setrefs.c.)
+ * other targets will be used for computing the final results.
*
* If we are grouping or aggregating, *and* there are no non-Var grouping
* expressions, then the returned tlist is effectively dummy; we do not
* need to force it to be evaluated, because all the Vars it contains
- * should be present in the output of query_planner anyway.
+ * should be present in the "flat" tlist generated by create_plan, though
+ * possibly in a different order. In that case we'll use create_plan's tlist,
+ * and the tlist made here is only needed as input to query_planner to tell
+ * it which Vars are needed in the output of the scan/join plan.
*
* 'tlist' is the query's target list.
* 'groupColIdx' receives an array of column numbers for the GROUP BY
- * expressions (if there are any) in the subplan's target list.
+ * expressions (if there are any) in the returned target list.
* 'need_tlist_eval' is set true if we really need to evaluate the
- * result tlist.
+ * returned tlist as-is.
*
- * The result is the targetlist to be passed to the subplan.
- *---------------
+ * The result is the targetlist to be passed to query_planner.
*/
static List *
make_subplanTargetList(PlannerInfo *root,
{
Query *parse = root->parse;
List *sub_tlist;
- List *extravars;
+ List *non_group_cols;
+ List *non_group_vars;
int numCols;
*groupColIdx = NULL;
* If we're not grouping or aggregating, there's nothing to do here;
* query_planner should receive the unmodified target list.
*/
- if (!parse->hasAggs && !parse->groupClause && !root->hasHavingQual)
+ if (!parse->hasAggs && !parse->groupClause && !root->hasHavingQual &&
+ !parse->hasWindowFuncs)
{
*need_tlist_eval = true;
return tlist;
}
/*
- * Otherwise, start with a "flattened" tlist (having just the vars
- * mentioned in the targetlist and HAVING qual --- but not upper-level
- * Vars; they will be replaced by Params later on).
+ * Otherwise, we must build a tlist containing all grouping columns, plus
+ * any other Vars mentioned in the targetlist and HAVING qual.
*/
- sub_tlist = flatten_tlist(tlist);
- extravars = pull_var_clause(parse->havingQual, false);
- sub_tlist = add_to_flat_tlist(sub_tlist, extravars);
- list_free(extravars);
+ sub_tlist = NIL;
+ non_group_cols = NIL;
*need_tlist_eval = false; /* only eval if not flat tlist */
- /*
- * If grouping, create sub_tlist entries for all GROUP BY expressions
- * (GROUP BY items that are simple Vars should be in the list already),
- * and make an array showing where the group columns are in the sub_tlist.
- */
numCols = list_length(parse->groupClause);
if (numCols > 0)
{
- int keyno = 0;
+ /*
+ * If grouping, create sub_tlist entries for all GROUP BY columns, and
+ * make an array showing where the group columns are in the sub_tlist.
+ *
+ * Note: with this implementation, the array entries will always be
+ * 1..N, but we don't want callers to assume that.
+ */
AttrNumber *grpColIdx;
- ListCell *gl;
+ ListCell *tl;
- grpColIdx = (AttrNumber *) palloc(sizeof(AttrNumber) * numCols);
+ grpColIdx = (AttrNumber *) palloc0(sizeof(AttrNumber) * numCols);
*groupColIdx = grpColIdx;
- foreach(gl, parse->groupClause)
+ foreach(tl, tlist)
{
- SortGroupClause *grpcl = (SortGroupClause *) lfirst(gl);
- Node *groupexpr = get_sortgroupclause_expr(grpcl, tlist);
- TargetEntry *te = NULL;
+ TargetEntry *tle = (TargetEntry *) lfirst(tl);
+ int colno;
- /*
- * Find or make a matching sub_tlist entry. If the groupexpr
- * isn't a Var, no point in searching. (Note that the parser
- * won't make multiple groupClause entries for the same TLE.)
- */
- if (groupexpr && IsA(groupexpr, Var))
+ colno = get_grouping_column_index(parse, tle);
+ if (colno >= 0)
{
- ListCell *sl;
+ /*
+ * It's a grouping column, so add it to the result tlist and
+ * remember its resno in grpColIdx[].
+ */
+ TargetEntry *newtle;
- foreach(sl, sub_tlist)
- {
- TargetEntry *lte = (TargetEntry *) lfirst(sl);
+ newtle = makeTargetEntry(tle->expr,
+ list_length(sub_tlist) + 1,
+ NULL,
+ false);
+ sub_tlist = lappend(sub_tlist, newtle);
- if (equal(groupexpr, lte->expr))
- {
- te = lte;
- break;
- }
- }
+ Assert(grpColIdx[colno] == 0); /* no dups expected */
+ grpColIdx[colno] = newtle->resno;
+
+ if (!(newtle->expr && IsA(newtle->expr, Var)))
+ *need_tlist_eval = true; /* tlist contains non Vars */
}
- if (!te)
+ else
{
- te = makeTargetEntry((Expr *) groupexpr,
- list_length(sub_tlist) + 1,
- NULL,
- false);
- sub_tlist = lappend(sub_tlist, te);
- *need_tlist_eval = true; /* it's not flat anymore */
+ /*
+ * Non-grouping column, so just remember the expression for
+ * later call to pull_var_clause. There's no need for
+ * pull_var_clause to examine the TargetEntry node itself.
+ */
+ non_group_cols = lappend(non_group_cols, tle->expr);
}
-
- /* and save its resno */
- grpColIdx[keyno++] = te->resno;
}
}
+ else
+ {
+ /*
+ * With no grouping columns, just pass whole tlist to pull_var_clause.
+ * Need (shallow) copy to avoid damaging input tlist below.
+ */
+ non_group_cols = list_copy(tlist);
+ }
+
+ /*
+ * If there's a HAVING clause, we'll need the Vars it uses, too.
+ */
+ if (parse->havingQual)
+ non_group_cols = lappend(non_group_cols, parse->havingQual);
+
+ /*
+ * Pull out all the Vars mentioned in non-group cols (plus HAVING), and
+ * add them to the result tlist if not already present. (A Var used
+ * directly as a GROUP BY item will be present already.) Note this
+ * includes Vars used in resjunk items, so we are covering the needs of
+ * ORDER BY and window specifications. Vars used within Aggrefs will be
+ * pulled out here, too.
+ */
+ non_group_vars = pull_var_clause((Node *) non_group_cols,
+ PVC_RECURSE_AGGREGATES,
+ PVC_INCLUDE_PLACEHOLDERS);
+ sub_tlist = add_to_flat_tlist(sub_tlist, non_group_vars);
+
+ /* clean up cruft */
+ list_free(non_group_vars);
+ list_free(non_group_cols);
return sub_tlist;
}
+/*
+ * get_grouping_column_index
+ * Get the GROUP BY column position, if any, of a targetlist entry.
+ *
+ * Returns the index (counting from 0) of the TLE in the GROUP BY list, or -1
+ * if it's not a grouping column. Note: the result is unique because the
+ * parser won't make multiple groupClause entries for the same TLE.
+ */
+static int
+get_grouping_column_index(Query *parse, TargetEntry *tle)
+{
+ int colno = 0;
+ Index ressortgroupref = tle->ressortgroupref;
+ ListCell *gl;
+
+ /* No need to search groupClause if TLE hasn't got a sortgroupref */
+ if (ressortgroupref == 0)
+ return -1;
+
+ foreach(gl, parse->groupClause)
+ {
+ SortGroupClause *grpcl = (SortGroupClause *) lfirst(gl);
+
+ if (grpcl->tleSortGroupRef == ressortgroupref)
+ return colno;
+ colno++;
+ }
+
+ return -1;
+}
+
/*
* locate_grouping_columns
- * Locate grouping columns in the tlist chosen by query_planner.
+ * Locate grouping columns in the tlist chosen by create_plan.
*
* This is only needed if we don't use the sub_tlist chosen by
* make_subplanTargetList. We have to forget the column indexes found
- * by that routine and re-locate the grouping vars in the real sub_tlist.
+ * by that routine and re-locate the grouping exprs in the real sub_tlist.
*/
static void
locate_grouping_columns(PlannerInfo *root,
{
SortGroupClause *grpcl = (SortGroupClause *) lfirst(gl);
Node *groupexpr = get_sortgroupclause_expr(grpcl, tlist);
- TargetEntry *te = NULL;
- ListCell *sl;
+ TargetEntry *te = tlist_member(groupexpr, sub_tlist);
- foreach(sl, sub_tlist)
- {
- te = (TargetEntry *) lfirst(sl);
- if (equal(groupexpr, te->expr))
- break;
- }
- if (!sl)
+ if (!te)
elog(ERROR, "failed to locate grouping columns");
-
groupColIdx[keyno++] = te->resno;
}
}
elog(ERROR, "resjunk output columns are not implemented");
return new_tlist;
}
+
+/*
+ * select_active_windows
+ * Create a list of the "active" window clauses (ie, those referenced
+ * by non-deleted WindowFuncs) in the order they are to be executed.
+ */
+static List *
+select_active_windows(PlannerInfo *root, WindowFuncLists *wflists)
+{
+ List *result;
+ List *actives;
+ ListCell *lc;
+
+ /* First, make a list of the active windows */
+ actives = NIL;
+ foreach(lc, root->parse->windowClause)
+ {
+ WindowClause *wc = (WindowClause *) lfirst(lc);
+
+ /* It's only active if wflists shows some related WindowFuncs */
+ Assert(wc->winref <= wflists->maxWinRef);
+ if (wflists->windowFuncs[wc->winref] != NIL)
+ actives = lappend(actives, wc);
+ }
+
+ /*
+ * Now, ensure that windows with identical partitioning/ordering clauses
+ * are adjacent in the list. This is required by the SQL standard, which
+ * says that only one sort is to be used for such windows, even if they
+ * are otherwise distinct (eg, different names or framing clauses).
+ *
+ * There is room to be much smarter here, for example detecting whether
+ * one window's sort keys are a prefix of another's (so that sorting for
+ * the latter would do for the former), or putting windows first that
+ * match a sort order available for the underlying query. For the moment
+ * we are content with meeting the spec.
+ */
+ result = NIL;
+ while (actives != NIL)
+ {
+ WindowClause *wc = (WindowClause *) linitial(actives);
+ ListCell *prev;
+ ListCell *next;
+
+ /* Move wc from actives to result */
+ actives = list_delete_first(actives);
+ result = lappend(result, wc);
+
+ /* Now move any matching windows from actives to result */
+ prev = NULL;
+ for (lc = list_head(actives); lc; lc = next)
+ {
+ WindowClause *wc2 = (WindowClause *) lfirst(lc);
+
+ next = lnext(lc);
+ /* framing options are NOT to be compared here! */
+ if (equal(wc->partitionClause, wc2->partitionClause) &&
+ equal(wc->orderClause, wc2->orderClause))
+ {
+ actives = list_delete_cell(actives, lc, prev);
+ result = lappend(result, wc2);
+ }
+ else
+ prev = lc;
+ }
+ }
+
+ return result;
+}
+
+/*
+ * add_volatile_sort_exprs
+ * Identify any volatile sort/group expressions used by the active
+ * windows, and add them to window_tlist if not already present.
+ * Return the modified window_tlist.
+ */
+static List *
+add_volatile_sort_exprs(List *window_tlist, List *tlist, List *activeWindows)
+{
+ Bitmapset *sgrefs = NULL;
+ ListCell *lc;
+
+ /* First, collect the sortgrouprefs of the windows into a bitmapset */
+ foreach(lc, activeWindows)
+ {
+ WindowClause *wc = (WindowClause *) lfirst(lc);
+ ListCell *lc2;
+
+ foreach(lc2, wc->partitionClause)
+ {
+ SortGroupClause *sortcl = (SortGroupClause *) lfirst(lc2);
+
+ sgrefs = bms_add_member(sgrefs, sortcl->tleSortGroupRef);
+ }
+ foreach(lc2, wc->orderClause)
+ {
+ SortGroupClause *sortcl = (SortGroupClause *) lfirst(lc2);
+
+ sgrefs = bms_add_member(sgrefs, sortcl->tleSortGroupRef);
+ }
+ }
+
+ /*
+ * Now scan the original tlist to find the referenced expressions. Any
+ * that are volatile must be added to window_tlist.
+ *
+ * Note: we know that the input window_tlist contains no items marked with
+ * ressortgrouprefs, so we don't have to worry about collisions of the
+ * reference numbers.
+ */
+ foreach(lc, tlist)
+ {
+ TargetEntry *tle = (TargetEntry *) lfirst(lc);
+
+ if (tle->ressortgroupref != 0 &&
+ bms_is_member(tle->ressortgroupref, sgrefs) &&
+ contain_volatile_functions((Node *) tle->expr))
+ {
+ TargetEntry *newtle;
+
+ newtle = makeTargetEntry(tle->expr,
+ list_length(window_tlist) + 1,
+ NULL,
+ false);
+ newtle->ressortgroupref = tle->ressortgroupref;
+ window_tlist = lappend(window_tlist, newtle);
+ }
+ }
+
+ return window_tlist;
+}
+
+/*
+ * make_pathkeys_for_window
+ * Create a pathkeys list describing the required input ordering
+ * for the given WindowClause.
+ *
+ * The required ordering is first the PARTITION keys, then the ORDER keys.
+ * In the future we might try to implement windowing using hashing, in which
+ * case the ordering could be relaxed, but for now we always sort.
+ */
+static List *
+make_pathkeys_for_window(PlannerInfo *root, WindowClause *wc,
+ List *tlist, bool canonicalize)
+{
+ List *window_pathkeys;
+ List *window_sortclauses;
+
+ /* Throw error if can't sort */
+ if (!grouping_is_sortable(wc->partitionClause))
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("could not implement window PARTITION BY"),
+ errdetail("Window partitioning columns must be of sortable datatypes.")));
+ if (!grouping_is_sortable(wc->orderClause))
+ ereport(ERROR,
+ (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+ errmsg("could not implement window ORDER BY"),
+ errdetail("Window ordering columns must be of sortable datatypes.")));
+
+ /* Okay, make the combined pathkeys */
+ window_sortclauses = list_concat(list_copy(wc->partitionClause),
+ list_copy(wc->orderClause));
+ window_pathkeys = make_pathkeys_for_sortclauses(root,
+ window_sortclauses,
+ tlist,
+ canonicalize);
+ list_free(window_sortclauses);
+ return window_pathkeys;
+}
+
+/*----------
+ * get_column_info_for_window
+ * Get the partitioning/ordering column numbers and equality operators
+ * for a WindowAgg node.
+ *
+ * This depends on the behavior of make_pathkeys_for_window()!
+ *
+ * We are given the target WindowClause and an array of the input column
+ * numbers associated with the resulting pathkeys. In the easy case, there
+ * are the same number of pathkey columns as partitioning + ordering columns
+ * and we just have to copy some data around. However, it's possible that
+ * some of the original partitioning + ordering columns were eliminated as
+ * redundant during the transformation to pathkeys. (This can happen even
+ * though the parser gets rid of obvious duplicates. A typical scenario is a
+ * window specification "PARTITION BY x ORDER BY y" coupled with a clause
+ * "WHERE x = y" that causes the two sort columns to be recognized as
+ * redundant.) In that unusual case, we have to work a lot harder to
+ * determine which keys are significant.
+ *
+ * The method used here is a bit brute-force: add the sort columns to a list
+ * one at a time and note when the resulting pathkey list gets longer. But
+ * it's a sufficiently uncommon case that a faster way doesn't seem worth
+ * the amount of code refactoring that'd be needed.
+ *----------
+ */
+static void
+get_column_info_for_window(PlannerInfo *root, WindowClause *wc, List *tlist,
+ int numSortCols, AttrNumber *sortColIdx,
+ int *partNumCols,
+ AttrNumber **partColIdx,
+ Oid **partOperators,
+ int *ordNumCols,
+ AttrNumber **ordColIdx,
+ Oid **ordOperators)
+{
+ int numPart = list_length(wc->partitionClause);
+ int numOrder = list_length(wc->orderClause);
+
+ if (numSortCols == numPart + numOrder)
+ {
+ /* easy case */
+ *partNumCols = numPart;
+ *partColIdx = sortColIdx;
+ *partOperators = extract_grouping_ops(wc->partitionClause);
+ *ordNumCols = numOrder;
+ *ordColIdx = sortColIdx + numPart;
+ *ordOperators = extract_grouping_ops(wc->orderClause);
+ }
+ else
+ {
+ List *sortclauses;
+ List *pathkeys;
+ int scidx;
+ ListCell *lc;
+
+ /* first, allocate what's certainly enough space for the arrays */
+ *partNumCols = 0;
+ *partColIdx = (AttrNumber *) palloc(numPart * sizeof(AttrNumber));
+ *partOperators = (Oid *) palloc(numPart * sizeof(Oid));
+ *ordNumCols = 0;
+ *ordColIdx = (AttrNumber *) palloc(numOrder * sizeof(AttrNumber));
+ *ordOperators = (Oid *) palloc(numOrder * sizeof(Oid));
+ sortclauses = NIL;
+ pathkeys = NIL;
+ scidx = 0;
+ foreach(lc, wc->partitionClause)
+ {
+ SortGroupClause *sgc = (SortGroupClause *) lfirst(lc);
+ List *new_pathkeys;
+
+ sortclauses = lappend(sortclauses, sgc);
+ new_pathkeys = make_pathkeys_for_sortclauses(root,
+ sortclauses,
+ tlist,
+ true);
+ if (list_length(new_pathkeys) > list_length(pathkeys))
+ {
+ /* this sort clause is actually significant */
+ (*partColIdx)[*partNumCols] = sortColIdx[scidx++];
+ (*partOperators)[*partNumCols] = sgc->eqop;
+ (*partNumCols)++;
+ pathkeys = new_pathkeys;
+ }
+ }
+ foreach(lc, wc->orderClause)
+ {
+ SortGroupClause *sgc = (SortGroupClause *) lfirst(lc);
+ List *new_pathkeys;
+
+ sortclauses = lappend(sortclauses, sgc);
+ new_pathkeys = make_pathkeys_for_sortclauses(root,
+ sortclauses,
+ tlist,
+ true);
+ if (list_length(new_pathkeys) > list_length(pathkeys))
+ {
+ /* this sort clause is actually significant */
+ (*ordColIdx)[*ordNumCols] = sortColIdx[scidx++];
+ (*ordOperators)[*ordNumCols] = sgc->eqop;
+ (*ordNumCols)++;
+ pathkeys = new_pathkeys;
+ }
+ }
+ /* complain if we didn't eat exactly the right number of sort cols */
+ if (scidx != numSortCols)
+ elog(ERROR, "failed to deconstruct sort operators into partitioning/ordering operators");
+ }
+}
+
+
+/*
+ * expression_planner
+ * Perform planner's transformations on a standalone expression.
+ *
+ * Various utility commands need to evaluate expressions that are not part
+ * of a plannable query. They can do so using the executor's regular
+ * expression-execution machinery, but first the expression has to be fed
+ * through here to transform it from parser output to something executable.
+ *
+ * Currently, we disallow sublinks in standalone expressions, so there's no
+ * real "planning" involved here. (That might not always be true though.)
+ * What we must do is run eval_const_expressions to ensure that any function
+ * calls are converted to positional notation and function default arguments
+ * get inserted. The fact that constant subexpressions get simplified is a
+ * side-effect that is useful when the expression will get evaluated more than
+ * once. Also, we must fix operator function IDs.
+ *
+ * Note: this must not make any damaging changes to the passed-in expression
+ * tree. (It would actually be okay to apply fix_opfuncids to it, but since
+ * we first do an expression_tree_mutator-based walk, what is returned will
+ * be a new node tree.)
+ */
+Expr *
+expression_planner(Expr *expr)
+{
+ Node *result;
+
+ /*
+ * Convert named-argument function calls, insert default arguments and
+ * simplify constant subexprs
+ */
+ result = eval_const_expressions(NULL, (Node *) expr);
+
+ /* Fill in opfuncid values if missing */
+ fix_opfuncids(result);
+
+ return (Expr *) result;
+}
+
+
+/*
+ * plan_cluster_use_sort
+ * Use the planner to decide how CLUSTER should implement sorting
+ *
+ * tableOid is the OID of a table to be clustered on its index indexOid
+ * (which is already known to be a btree index). Decide whether it's
+ * cheaper to do an indexscan or a seqscan-plus-sort to execute the CLUSTER.
+ * Return TRUE to use sorting, FALSE to use an indexscan.
+ *
+ * Note: caller had better already hold some type of lock on the table.
+ */
+bool
+plan_cluster_use_sort(Oid tableOid, Oid indexOid)
+{
+ PlannerInfo *root;
+ Query *query;
+ PlannerGlobal *glob;
+ RangeTblEntry *rte;
+ RelOptInfo *rel;
+ IndexOptInfo *indexInfo;
+ QualCost indexExprCost;
+ Cost comparisonCost;
+ Path *seqScanPath;
+ Path seqScanAndSortPath;
+ IndexPath *indexScanPath;
+ ListCell *lc;
+
+ /* Set up mostly-dummy planner state */
+ query = makeNode(Query);
+ query->commandType = CMD_SELECT;
+
+ glob = makeNode(PlannerGlobal);
+
+ root = makeNode(PlannerInfo);
+ root->parse = query;
+ root->glob = glob;
+ root->query_level = 1;
+ root->planner_cxt = CurrentMemoryContext;
+ root->wt_param_id = -1;
+
+ /* Build a minimal RTE for the rel */
+ rte = makeNode(RangeTblEntry);
+ rte->rtekind = RTE_RELATION;
+ rte->relid = tableOid;
+ rte->relkind = RELKIND_RELATION;
+ rte->lateral = false;
+ rte->inh = false;
+ rte->inFromCl = true;
+ query->rtable = list_make1(rte);
+
+ /* Set up RTE/RelOptInfo arrays */
+ setup_simple_rel_arrays(root);
+
+ /* Build RelOptInfo */
+ rel = build_simple_rel(root, 1, RELOPT_BASEREL);
+
+ /* Locate IndexOptInfo for the target index */
+ indexInfo = NULL;
+ foreach(lc, rel->indexlist)
+ {
+ indexInfo = (IndexOptInfo *) lfirst(lc);
+ if (indexInfo->indexoid == indexOid)
+ break;
+ }
+
+ /*
+ * It's possible that get_relation_info did not generate an IndexOptInfo
+ * for the desired index; this could happen if it's not yet reached its
+ * indcheckxmin usability horizon, or if it's a system index and we're
+ * ignoring system indexes. In such cases we should tell CLUSTER to not
+ * trust the index contents but use seqscan-and-sort.
+ */
+ if (lc == NULL) /* not in the list? */
+ return true; /* use sort */
+
+ /*
+ * Rather than doing all the pushups that would be needed to use
+ * set_baserel_size_estimates, just do a quick hack for rows and width.
+ */
+ rel->rows = rel->tuples;
+ rel->width = get_relation_data_width(tableOid, NULL);
+
+ root->total_table_pages = rel->pages;
+
+ /*
+ * Determine eval cost of the index expressions, if any. We need to
+ * charge twice that amount for each tuple comparison that happens during
+ * the sort, since tuplesort.c will have to re-evaluate the index
+ * expressions each time. (XXX that's pretty inefficient...)
+ */
+ cost_qual_eval(&indexExprCost, indexInfo->indexprs, root);
+ comparisonCost = 2.0 * (indexExprCost.startup + indexExprCost.per_tuple);
+
+ /* Estimate the cost of seq scan + sort */
+ seqScanPath = create_seqscan_path(root, rel, NULL);
+ cost_sort(&seqScanAndSortPath, root, NIL,
+ seqScanPath->total_cost, rel->tuples, rel->width,
+ comparisonCost, maintenance_work_mem, -1.0);
+
+ /* Estimate the cost of index scan */
+ indexScanPath = create_index_path(root, indexInfo,
+ NIL, NIL, NIL, NIL, NIL,
+ ForwardScanDirection, false,
+ NULL, 1.0);
+
+ return (seqScanAndSortPath.total_cost < indexScanPath->path.total_cost);
+}
projects / postgresql / blobdiff