*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.136 2002/12/19 23:25:01 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planner.c,v 1.152 2003/03/13 16:58:35 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "catalog/pg_operator.h"
#include "catalog/pg_type.h"
+#include "executor/executor.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#ifdef OPTIMIZER_DEBUG
#include "parser/parsetree.h"
#include "parser/parse_expr.h"
#include "parser/parse_oper.h"
-#include "rewrite/rewriteManip.h"
-#include "utils/lsyscache.h"
#include "utils/selfuncs.h"
#include "utils/syscache.h"
/* Expression kind codes for preprocess_expression */
-#define EXPRKIND_TARGET 0
-#define EXPRKIND_WHERE 1
-#define EXPRKIND_HAVING 2
+#define EXPRKIND_QUAL 0
+#define EXPRKIND_TARGET 1
+#define EXPRKIND_RTFUNC 2
+#define EXPRKIND_ININFO 3
-static Node *pull_up_subqueries(Query *parse, Node *jtnode,
- bool below_outer_join);
-static bool is_simple_subquery(Query *subquery);
-static bool has_nullable_targetlist(Query *subquery);
-static void resolvenew_in_jointree(Node *jtnode, int varno, List *subtlist);
-static Node *preprocess_jointree(Query *parse, Node *jtnode);
static Node *preprocess_expression(Query *parse, Node *expr, int kind);
static void preprocess_qual_conditions(Query *parse, Node *jtnode);
static Plan *inheritance_planner(Query *parse, List *inheritlist);
static Plan *grouping_planner(Query *parse, double tuple_fraction);
static bool hash_safe_grouping(Query *parse);
static List *make_subplanTargetList(Query *parse, List *tlist,
- AttrNumber **groupColIdx);
+ AttrNumber **groupColIdx, bool *need_tlist_eval);
+static void locate_grouping_columns(Query *parse,
+ List *tlist,
+ List *sub_tlist,
+ AttrNumber *groupColIdx);
static Plan *make_groupsortplan(Query *parse,
List *groupClause,
AttrNumber *grpColIdx,
*
*****************************************************************************/
Plan *
-planner(Query *parse)
+planner(Query *parse, bool isCursor, int cursorOptions)
{
+ double tuple_fraction;
Plan *result_plan;
Index save_PlannerQueryLevel;
List *save_PlannerParamVar;
PlannerQueryLevel = 0; /* will be 1 in top-level subquery_planner */
PlannerParamVar = NIL;
+ /* Determine what fraction of the plan is likely to be scanned */
+ if (isCursor)
+ {
+ /*
+ * We have no real idea how many tuples the user will ultimately
+ * FETCH from a cursor, but it seems a good bet that he
+ * doesn't want 'em all. Optimize for 10% retrieval (you
+ * gotta better number? Should this be a SETtable parameter?)
+ */
+ tuple_fraction = 0.10;
+ }
+ else
+ {
+ /* Default assumption is we need all the tuples */
+ tuple_fraction = 0.0;
+ }
+
/* primary planning entry point (may recurse for subqueries) */
- result_plan = subquery_planner(parse, -1.0 /* default case */ );
+ result_plan = subquery_planner(parse, tuple_fraction);
Assert(PlannerQueryLevel == 0);
+ /*
+ * If creating a plan for a scrollable cursor, make sure it can
+ * run backwards on demand. Add a Material node at the top at need.
+ */
+ if (isCursor && (cursorOptions & CURSOR_OPT_SCROLL))
+ {
+ if (!ExecSupportsBackwardScan(result_plan))
+ result_plan = materialize_finished_plan(result_plan);
+ }
+
/* executor wants to know total number of Params used overall */
result_plan->nParamExec = length(PlannerParamVar);
{
List *saved_initplan = PlannerInitPlan;
int saved_planid = PlannerPlanId;
+ bool hasOuterJoins;
Plan *plan;
List *newHaving;
List *lst;
PlannerInitPlan = NIL;
/*
- * Check to see if any subqueries in the rangetable can be merged into
- * this query.
+ * Look for IN clauses at the top level of WHERE, and transform them
+ * into joins. Note that this step only handles IN clauses originally
+ * at top level of WHERE; if we pull up any subqueries in the next step,
+ * their INs are processed just before pulling them up.
*/
- parse->jointree = (FromExpr *)
- pull_up_subqueries(parse, (Node *) parse->jointree, false);
+ parse->in_info_list = NIL;
+ if (parse->hasSubLinks)
+ parse->jointree->quals = pull_up_IN_clauses(parse,
+ parse->jointree->quals);
/*
- * If so, we may have created opportunities to simplify the jointree.
+ * Check to see if any subqueries in the rangetable can be merged into
+ * this query.
*/
parse->jointree = (FromExpr *)
- preprocess_jointree(parse, (Node *) parse->jointree);
+ pull_up_subqueries(parse, (Node *) parse->jointree, false);
/*
* Detect whether any rangetable entries are RTE_JOIN kind; if not,
- * we can avoid the expense of doing flatten_join_alias_vars().
+ * 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.
*/
parse->hasJoinRTEs = false;
+ hasOuterJoins = false;
foreach(lst, parse->rtable)
{
RangeTblEntry *rte = (RangeTblEntry *) lfirst(lst);
if (rte->rtekind == RTE_JOIN)
{
parse->hasJoinRTEs = true;
- break;
+ if (IS_OUTER_JOIN(rte->jointype))
+ {
+ hasOuterJoins = true;
+ /* Can quit scanning once we find an outer join */
+ break;
+ }
}
}
preprocess_qual_conditions(parse, (Node *) parse->jointree);
parse->havingQual = preprocess_expression(parse, parse->havingQual,
- EXPRKIND_HAVING);
+ EXPRKIND_QUAL);
+
+ parse->in_info_list = (List *)
+ preprocess_expression(parse, (Node *) parse->in_info_list,
+ EXPRKIND_ININFO);
/* Also need to preprocess expressions for function RTEs */
foreach(lst, parse->rtable)
if (rte->rtekind == RTE_FUNCTION)
rte->funcexpr = preprocess_expression(parse, rte->funcexpr,
- EXPRKIND_TARGET);
- /* These are not targetlist items, but close enough... */
+ EXPRKIND_RTFUNC);
}
- /*
- * Check for ungrouped variables passed to subplans in targetlist and
- * HAVING clause (but not in WHERE or JOIN/ON clauses, since those are
- * evaluated before grouping). We can't do this any earlier because
- * we must use the preprocessed targetlist for comparisons of grouped
- * expressions.
- */
- if (parse->hasSubLinks &&
- (parse->groupClause != NIL || parse->hasAggs))
- check_subplans_for_ungrouped_vars(parse);
-
/*
* A HAVING clause without aggregates is equivalent to a WHERE clause
* (except it can only refer to grouped fields). Transfer any
}
parse->havingQual = (Node *) newHaving;
+ /*
+ * If we have any outer joins, try to reduce them to plain inner joins.
+ * This step is most easily done after we've done expression preprocessing.
+ */
+ if (hasOuterJoins)
+ reduce_outer_joins(parse);
+
+ /*
+ * See if we can simplify the jointree; opportunities for this may come
+ * from having pulled up subqueries, or from flattening explicit JOIN
+ * syntax. We must do this after flattening JOIN alias variables, since
+ * eliminating explicit JOIN nodes from the jointree will cause
+ * get_relids_for_join() to fail. But it should happen after
+ * reduce_outer_joins, anyway.
+ */
+ parse->jointree = (FromExpr *)
+ simplify_jointree(parse, (Node *) parse->jointree);
+
/*
* Do the main planning. If we have an inherited target relation,
* that needs special processing, else go straight to
* grouping_planner.
*/
if (parse->resultRelation &&
- (lst = expand_inherted_rtentry(parse, parse->resultRelation, false))
- != NIL)
+ (lst = expand_inherited_rtentry(parse, parse->resultRelation,
+ false)) != NIL)
plan = inheritance_planner(parse, lst);
else
plan = grouping_planner(parse, tuple_fraction);
/*
* If any subplans were generated, or if we're inside a subplan, build
- * initPlan, extParam and locParam lists for plan nodes.
+ * initPlan list and extParam/allParam sets for plan nodes.
*/
if (PlannerPlanId != saved_planid || PlannerQueryLevel > 1)
{
Cost initplan_cost = 0;
- /* Prepare extParam/locParam data for all nodes in tree */
- (void) SS_finalize_plan(plan, parse->rtable);
+ /* Prepare extParam/allParam sets for all nodes in tree */
+ SS_finalize_plan(plan, parse->rtable);
/*
* SS_finalize_plan doesn't handle initPlans, so we have to manually
{
SubPlan *initplan = (SubPlan *) lfirst(lst);
- plan->extParam = set_unioni(plan->extParam,
- initplan->plan->extParam);
+ plan->extParam = bms_add_members(plan->extParam,
+ initplan->plan->extParam);
initplan_cost += initplan->plan->total_cost;
}
return plan;
}
-/*
- * pull_up_subqueries
- * Look for subqueries in the rangetable that can be pulled up into
- * the parent query. If the subquery has no special features like
- * grouping/aggregation then we can merge it into the parent's jointree.
- *
- * below_outer_join is true if this jointree node is within the nullable
- * side of an outer join. This restricts what we can do.
- *
- * A tricky aspect of this code is that if we pull up a subquery we have
- * to replace Vars that reference the subquery's outputs throughout the
- * parent query, including quals attached to jointree nodes above the one
- * we are currently processing! We handle this by being careful not to
- * change the jointree structure while recursing: no nodes other than
- * subquery RangeTblRef entries will be replaced. Also, we can't turn
- * ResolveNew loose on the whole jointree, because it'll return a mutated
- * copy of the tree; we have to invoke it just on the quals, instead.
- */
-static Node *
-pull_up_subqueries(Query *parse, Node *jtnode, bool below_outer_join)
-{
- if (jtnode == NULL)
- return NULL;
- if (IsA(jtnode, RangeTblRef))
- {
- int varno = ((RangeTblRef *) jtnode)->rtindex;
- RangeTblEntry *rte = rt_fetch(varno, parse->rtable);
- Query *subquery = rte->subquery;
-
- /*
- * Is this a subquery RTE, and if so, is the subquery simple
- * enough to pull up? (If not, do nothing at this node.)
- *
- * If we are inside an outer join, only pull up subqueries whose
- * targetlists are nullable --- otherwise substituting their tlist
- * entries for upper Var references would do the wrong thing (the
- * results wouldn't become NULL when they're supposed to). XXX
- * This could be improved by generating pseudo-variables for such
- * expressions; we'd have to figure out how to get the pseudo-
- * variables evaluated at the right place in the modified plan
- * tree. Fix it someday.
- *
- * Note: even if the subquery itself is simple enough, we can't pull
- * it up if there is a reference to its whole tuple result.
- * Perhaps a pseudo-variable is the answer here too.
- */
- if (rte->rtekind == RTE_SUBQUERY && is_simple_subquery(subquery) &&
- (!below_outer_join || has_nullable_targetlist(subquery)) &&
- !contain_whole_tuple_var((Node *) parse, varno, 0))
- {
- int rtoffset;
- List *subtlist;
- List *rt;
-
- /*
- * First, recursively pull up the subquery's subqueries, so
- * that this routine's processing is complete for its jointree
- * and rangetable. NB: if the same subquery is referenced
- * from multiple jointree items (which can't happen normally,
- * but might after rule rewriting), then we will invoke this
- * processing multiple times on that subquery. OK because
- * nothing will happen after the first time. We do have to be
- * careful to copy everything we pull up, however, or risk
- * having chunks of structure multiply linked.
- *
- * Note: 'false' is correct here even if we are within an outer
- * join in the upper query; the lower query starts with a clean
- * slate for outer-join semantics.
- */
- subquery->jointree = (FromExpr *)
- pull_up_subqueries(subquery, (Node *) subquery->jointree,
- false);
-
- /*
- * Now make a modifiable copy of the subquery that we can run
- * OffsetVarNodes and IncrementVarSublevelsUp on.
- */
- subquery = copyObject(subquery);
-
- /*
- * Adjust level-0 varnos in subquery so that we can append its
- * rangetable to upper query's.
- */
- rtoffset = length(parse->rtable);
- OffsetVarNodes((Node *) subquery, rtoffset, 0);
-
- /*
- * Upper-level vars in subquery are now one level closer to their
- * parent than before.
- */
- IncrementVarSublevelsUp((Node *) subquery, -1, 1);
-
- /*
- * Replace all of the top query's references to the subquery's
- * outputs with copies of the adjusted subtlist items, being
- * careful not to replace any of the jointree structure.
- * (This'd be a lot cleaner if we could use
- * query_tree_mutator.)
- */
- subtlist = subquery->targetList;
- parse->targetList = (List *)
- ResolveNew((Node *) parse->targetList,
- varno, 0, subtlist, CMD_SELECT, 0);
- resolvenew_in_jointree((Node *) parse->jointree, varno, subtlist);
- Assert(parse->setOperations == NULL);
- parse->havingQual =
- ResolveNew(parse->havingQual,
- varno, 0, subtlist, CMD_SELECT, 0);
-
- foreach(rt, parse->rtable)
- {
- RangeTblEntry *rte = (RangeTblEntry *) lfirst(rt);
-
- if (rte->rtekind == RTE_JOIN)
- rte->joinaliasvars = (List *)
- ResolveNew((Node *) rte->joinaliasvars,
- varno, 0, subtlist, CMD_SELECT, 0);
- }
-
- /*
- * Now append the adjusted rtable entries to upper query. (We
- * hold off until after fixing the upper rtable entries; no
- * point in running that code on the subquery ones too.)
- */
- parse->rtable = nconc(parse->rtable, subquery->rtable);
-
- /*
- * Pull up any FOR UPDATE markers, too. (OffsetVarNodes
- * already adjusted the marker values, so just nconc the
- * list.)
- */
- parse->rowMarks = nconc(parse->rowMarks, subquery->rowMarks);
-
- /*
- * Miscellaneous housekeeping.
- */
- parse->hasSubLinks |= subquery->hasSubLinks;
- /* subquery won't be pulled up if it hasAggs, so no work there */
-
- /*
- * Return the adjusted subquery jointree to replace the
- * RangeTblRef entry in my jointree.
- */
- return (Node *) subquery->jointree;
- }
- }
- else if (IsA(jtnode, FromExpr))
- {
- FromExpr *f = (FromExpr *) jtnode;
- List *l;
-
- foreach(l, f->fromlist)
- lfirst(l) = pull_up_subqueries(parse, lfirst(l),
- below_outer_join);
- }
- else if (IsA(jtnode, JoinExpr))
- {
- JoinExpr *j = (JoinExpr *) jtnode;
-
- /* Recurse, being careful to tell myself when inside outer join */
- switch (j->jointype)
- {
- case JOIN_INNER:
- j->larg = pull_up_subqueries(parse, j->larg,
- below_outer_join);
- j->rarg = pull_up_subqueries(parse, j->rarg,
- below_outer_join);
- break;
- case JOIN_LEFT:
- j->larg = pull_up_subqueries(parse, j->larg,
- below_outer_join);
- j->rarg = pull_up_subqueries(parse, j->rarg,
- true);
- break;
- case JOIN_FULL:
- j->larg = pull_up_subqueries(parse, j->larg,
- true);
- j->rarg = pull_up_subqueries(parse, j->rarg,
- true);
- break;
- case JOIN_RIGHT:
- j->larg = pull_up_subqueries(parse, j->larg,
- true);
- j->rarg = pull_up_subqueries(parse, j->rarg,
- below_outer_join);
- break;
- case JOIN_UNION:
-
- /*
- * This is where we fail if upper levels of planner
- * haven't rewritten UNION JOIN as an Append ...
- */
- elog(ERROR, "UNION JOIN is not implemented yet");
- break;
- default:
- elog(ERROR, "pull_up_subqueries: unexpected join type %d",
- j->jointype);
- break;
- }
- }
- else
- elog(ERROR, "pull_up_subqueries: unexpected node type %d",
- nodeTag(jtnode));
- return jtnode;
-}
-
-/*
- * is_simple_subquery
- * Check a subquery in the range table to see if it's simple enough
- * to pull up into the parent query.
- */
-static bool
-is_simple_subquery(Query *subquery)
-{
- /*
- * Let's just make sure it's a valid subselect ...
- */
- if (!IsA(subquery, Query) ||
- subquery->commandType != CMD_SELECT ||
- subquery->resultRelation != 0 ||
- subquery->into != NULL ||
- subquery->isPortal)
- elog(ERROR, "is_simple_subquery: subquery is bogus");
-
- /*
- * Can't currently pull up a query with setops. Maybe after querytree
- * redesign...
- */
- if (subquery->setOperations)
- return false;
-
- /*
- * Can't pull up a subquery involving grouping, aggregation, sorting,
- * or limiting.
- */
- if (subquery->hasAggs ||
- subquery->groupClause ||
- subquery->havingQual ||
- subquery->sortClause ||
- subquery->distinctClause ||
- subquery->limitOffset ||
- subquery->limitCount)
- return false;
-
- /*
- * Don't pull up a subquery that has any set-returning functions in
- * its targetlist. Otherwise we might well wind up inserting
- * set-returning functions into places where they mustn't go, such as
- * quals of higher queries.
- */
- if (expression_returns_set((Node *) subquery->targetList))
- return false;
-
- /*
- * Don't pull up a subquery that has any sublinks in its targetlist,
- * either. As of PG 7.3 this creates problems because the pulled-up
- * expressions may go into join alias lists, and the sublinks would
- * not get fixed because we do flatten_join_alias_vars() too late.
- * Eventually we should do a complete flatten_join_alias_vars as the
- * first step of preprocess_expression, and then we could probably
- * support this. (BUT: it might be a bad idea anyway, due to possibly
- * causing multiple evaluations of an expensive sublink.)
- */
- if (subquery->hasSubLinks &&
- contain_subplans((Node *) subquery->targetList))
- return false;
-
- /*
- * Hack: don't try to pull up a subquery with an empty jointree.
- * query_planner() will correctly generate a Result plan for a
- * jointree that's totally empty, but I don't think the right things
- * happen if an empty FromExpr appears lower down in a jointree. Not
- * worth working hard on this, just to collapse SubqueryScan/Result
- * into Result...
- */
- if (subquery->jointree->fromlist == NIL)
- return false;
-
- return true;
-}
-
-/*
- * has_nullable_targetlist
- * Check a subquery in the range table to see if all the non-junk
- * targetlist items are simple variables (and, hence, will correctly
- * go to NULL when examined above the point of an outer join).
- *
- * A possible future extension is to accept strict functions of simple
- * variables, eg, "x + 1".
- */
-static bool
-has_nullable_targetlist(Query *subquery)
-{
- List *l;
-
- foreach(l, subquery->targetList)
- {
- TargetEntry *tle = (TargetEntry *) lfirst(l);
-
- /* ignore resjunk columns */
- if (tle->resdom->resjunk)
- continue;
-
- /* Okay if tlist item is a simple Var */
- if (tle->expr && IsA(tle->expr, Var))
- continue;
-
- return false;
- }
- return true;
-}
-
-/*
- * Helper routine for pull_up_subqueries: do ResolveNew on every expression
- * in the jointree, without changing the jointree structure itself. Ugly,
- * but there's no other way...
- */
-static void
-resolvenew_in_jointree(Node *jtnode, int varno, List *subtlist)
-{
- if (jtnode == NULL)
- return;
- if (IsA(jtnode, RangeTblRef))
- {
- /* nothing to do here */
- }
- else if (IsA(jtnode, FromExpr))
- {
- FromExpr *f = (FromExpr *) jtnode;
- List *l;
-
- foreach(l, f->fromlist)
- resolvenew_in_jointree(lfirst(l), varno, subtlist);
- f->quals = ResolveNew(f->quals,
- varno, 0, subtlist, CMD_SELECT, 0);
- }
- else if (IsA(jtnode, JoinExpr))
- {
- JoinExpr *j = (JoinExpr *) jtnode;
-
- resolvenew_in_jointree(j->larg, varno, subtlist);
- resolvenew_in_jointree(j->rarg, varno, subtlist);
- j->quals = ResolveNew(j->quals,
- varno, 0, subtlist, CMD_SELECT, 0);
-
- /*
- * We don't bother to update the colvars list, since it won't be
- * used again ...
- */
- }
- else
- elog(ERROR, "resolvenew_in_jointree: unexpected node type %d",
- nodeTag(jtnode));
-}
-
-/*
- * preprocess_jointree
- * Attempt to simplify a query's jointree.
- *
- * If we succeed in pulling up a subquery then we might form a jointree
- * in which a FromExpr is a direct child of another FromExpr. In that
- * case we can consider collapsing the two FromExprs into one. This is
- * an optional conversion, since the planner will work correctly either
- * way. But we may find a better plan (at the cost of more planning time)
- * if we merge the two nodes.
- *
- * NOTE: don't try to do this in the same jointree scan that does subquery
- * pullup! Since we're changing the jointree structure here, that wouldn't
- * work reliably --- see comments for pull_up_subqueries().
- */
-static Node *
-preprocess_jointree(Query *parse, Node *jtnode)
-{
- if (jtnode == NULL)
- return NULL;
- if (IsA(jtnode, RangeTblRef))
- {
- /* nothing to do here... */
- }
- else if (IsA(jtnode, FromExpr))
- {
- FromExpr *f = (FromExpr *) jtnode;
- List *newlist = NIL;
- List *l;
-
- foreach(l, f->fromlist)
- {
- Node *child = (Node *) lfirst(l);
-
- /* Recursively simplify the child... */
- child = preprocess_jointree(parse, child);
- /* Now, is it a FromExpr? */
- if (child && IsA(child, FromExpr))
- {
- /*
- * Yes, so do we want to merge it into parent? Always do
- * so if child has just one element (since that doesn't
- * make the parent's list any longer). Otherwise we have
- * to be careful about the increase in planning time
- * caused by combining the two join search spaces into
- * one. Our heuristic is to merge if the merge will
- * produce a join list no longer than GEQO_RELS/2.
- * (Perhaps need an additional user parameter?)
- */
- FromExpr *subf = (FromExpr *) child;
- int childlen = length(subf->fromlist);
- int myothers = length(newlist) + length(lnext(l));
-
- if (childlen <= 1 || (childlen + myothers) <= geqo_rels / 2)
- {
- newlist = nconc(newlist, subf->fromlist);
- f->quals = make_and_qual(subf->quals, f->quals);
- }
- else
- newlist = lappend(newlist, child);
- }
- else
- newlist = lappend(newlist, child);
- }
- f->fromlist = newlist;
- }
- else if (IsA(jtnode, JoinExpr))
- {
- JoinExpr *j = (JoinExpr *) jtnode;
-
- /* Can't usefully change the JoinExpr, but recurse on children */
- j->larg = preprocess_jointree(parse, j->larg);
- j->rarg = preprocess_jointree(parse, j->rarg);
- }
- else
- elog(ERROR, "preprocess_jointree: unexpected node type %d",
- nodeTag(jtnode));
- return jtnode;
-}
-
/*
* preprocess_expression
* Do subquery_planner's preprocessing work for an expression,
static Node *
preprocess_expression(Query *parse, 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.
+ */
+ if (parse->hasJoinRTEs)
+ expr = flatten_join_alias_vars(parse, expr);
+
/*
* Simplify constant expressions.
*
* XXX Is there any value in re-applying eval_const_expressions after
* canonicalize_qual?
*/
- if (kind != EXPRKIND_TARGET)
+ if (kind == EXPRKIND_QUAL)
{
expr = (Node *) canonicalize_qual((Expr *) expr, true);
/* Expand SubLinks to SubPlans */
if (parse->hasSubLinks)
- expr = SS_process_sublinks(expr);
+ expr = SS_process_sublinks(expr, (kind == EXPRKIND_QUAL));
/* Replace uplevel vars with Param nodes */
if (PlannerQueryLevel > 1)
expr = SS_replace_correlation_vars(expr);
- /*
- * If the query has any join RTEs, try to replace join alias variables
- * with base-relation variables, to allow quals to be pushed down. We
- * must do this after sublink processing, since it does not recurse
- * into sublinks.
- */
- if (parse->hasJoinRTEs)
- expr = flatten_join_alias_vars(expr, parse->rtable, false);
-
return expr;
}
foreach(l, f->fromlist)
preprocess_qual_conditions(parse, lfirst(l));
- f->quals = preprocess_expression(parse, f->quals, EXPRKIND_WHERE);
+ f->quals = preprocess_expression(parse, f->quals, EXPRKIND_QUAL);
}
else if (IsA(jtnode, JoinExpr))
{
preprocess_qual_conditions(parse, j->larg);
preprocess_qual_conditions(parse, j->rarg);
- j->quals = preprocess_expression(parse, j->quals, EXPRKIND_WHERE);
+ j->quals = preprocess_expression(parse, j->quals, EXPRKIND_QUAL);
}
else
elog(ERROR, "preprocess_qual_conditions: unexpected node type %d",
{
int parentRTindex = parse->resultRelation;
Oid parentOID = getrelid(parentRTindex, parse->rtable);
+ int mainrtlength = length(parse->rtable);
List *subplans = NIL;
List *tlist = NIL;
List *l;
{
int childRTindex = lfirsti(l);
Oid childOID = getrelid(childRTindex, parse->rtable);
+ int subrtlength;
Query *subquery;
Plan *subplan;
/* Generate plan */
subplan = grouping_planner(subquery, 0.0 /* retrieve all tuples */ );
subplans = lappend(subplans, subplan);
+ /*
+ * It's possible that additional RTEs got added to the rangetable
+ * due to expansion of inherited source tables (see allpaths.c).
+ * If so, we must copy 'em back to the main parse tree's rtable.
+ *
+ * XXX my goodness this is ugly. Really need to think about ways
+ * to rein in planner's habit of scribbling on its input.
+ */
+ subrtlength = length(subquery->rtable);
+ if (subrtlength > mainrtlength)
+ {
+ List *subrt = subquery->rtable;
+
+ while (mainrtlength-- > 0) /* wish we had nthcdr() */
+ subrt = lnext(subrt);
+ parse->rtable = nconc(parse->rtable, subrt);
+ mainrtlength = subrtlength;
+ }
/* Save preprocessed tlist from first rel for use in Append */
if (tlist == NIL)
tlist = subplan->targetlist;
/* Save the target-relations list for the executor, too */
parse->resultRelations = inheritlist;
+ /* Mark result as unordered (probably unnecessary) */
+ parse->query_pathkeys = NIL;
+
return (Plan *) make_append(subplans, true, tlist);
}
* tuple_fraction is the fraction of tuples we expect will be retrieved
*
* tuple_fraction is interpreted as follows:
- * < 0: determine fraction by inspection of query (normal case)
- * 0: expect all tuples to be retrieved
+ * 0: expect all tuples to be retrieved (normal case)
* 0 < tuple_fraction < 1: expect the given fraction of tuples available
* from the plan to be retrieved
* tuple_fraction >= 1: tuple_fraction is the absolute number of tuples
* expected to be retrieved (ie, a LIMIT specification)
- * The normal case is to pass -1, but some callers pass values >= 0 to
- * override this routine's determination of the appropriate fraction.
*
- * Returns a query plan.
+ * Returns a query plan. Also, parse->query_pathkeys is returned as the
+ * actual output ordering of the plan (in pathkey format).
*--------------------
*/
static Plan *
List *sub_tlist;
List *group_pathkeys;
AttrNumber *groupColIdx = NULL;
+ bool need_tlist_eval = true;
+ QualCost tlist_cost;
double sub_tuple_fraction;
Path *cheapest_path;
Path *sorted_path;
* Generate appropriate target list for subplan; may be different
* from tlist if grouping or aggregation is needed.
*/
- sub_tlist = make_subplanTargetList(parse, tlist, &groupColIdx);
+ sub_tlist = make_subplanTargetList(parse, tlist,
+ &groupColIdx, &need_tlist_eval);
/*
* Calculate pathkeys that represent grouping/ordering
* Will need actual number of aggregates for estimating costs.
* Also, it's possible that optimization has eliminated all
* aggregates, and we may as well check for that here.
+ *
+ * Note: we do not attempt to detect duplicate aggregates here;
+ * a somewhat-overestimated count is okay for our present purposes.
*/
if (parse->hasAggs)
{
- numAggs = length(pull_agg_clause((Node *) tlist)) +
- length(pull_agg_clause(parse->havingQual));
+ numAggs = count_agg_clause((Node *) tlist) +
+ count_agg_clause(parse->havingQual);
if (numAggs == 0)
parse->hasAggs = false;
}
else
parse->query_pathkeys = NIL;
- /*
- * Figure out whether we expect to retrieve all the tuples that
- * the plan can generate, or to stop early due to outside factors
- * such as a cursor. If the caller passed a value >= 0, believe
- * that value, else do our own examination of the query context.
- */
- if (tuple_fraction < 0.0)
- {
- /* Initial assumption is we need all the tuples */
- tuple_fraction = 0.0;
-
- /*
- * Check for retrieve-into-portal, ie DECLARE CURSOR.
- *
- * We have no real idea how many tuples the user will ultimately
- * FETCH from a cursor, but it seems a good bet that he
- * doesn't want 'em all. Optimize for 10% retrieval (you
- * gotta better number? Should this be a SETtable parameter?)
- */
- if (parse->isPortal)
- tuple_fraction = 0.10;
- }
-
/*
* Adjust tuple_fraction if we see that we are going to apply
* limiting/grouping/aggregation/etc. This is not overridable by
*/
if (parse->groupClause)
{
+ List *groupExprs;
+
/*
* Always estimate the number of groups. We can't do this until
* after running query_planner(), either.
*/
+ groupExprs = get_sortgrouplist_exprs(parse->groupClause,
+ parse->targetList);
dNumGroups = estimate_num_groups(parse,
- parse->groupClause,
+ groupExprs,
cheapest_path->parent->rows);
/* Also want it as a long int --- but 'ware overflow! */
numGroups = (long) Min(dNumGroups, (double) LONG_MAX);
tuple_fraction /= dNumGroups;
if (compare_fractional_path_costs(&hashed_p, &sorted_p,
- tuple_fraction) <= 0)
+ tuple_fraction) < 0)
{
/* Hashed is cheaper, so use it */
use_hashed_grouping = true;
/*
* create_plan() returns a plan with just a "flat" tlist of required
- * Vars. We want to insert the sub_tlist as the tlist of the top
- * plan node. If the top-level plan node is one that cannot do
- * expression evaluation, we must insert a Result node to project the
- * desired tlist.
- * Currently, the only plan node we might see here that falls into
- * that category is Append.
+ * 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.
*/
- if (IsA(result_plan, Append))
+ if (need_tlist_eval)
{
- result_plan = (Plan *) make_result(sub_tlist, NULL, result_plan);
+ /*
+ * If the top-level plan node is one that cannot do expression
+ * evaluation, we must insert a Result node to project the desired
+ * tlist.
+ * Currently, the only plan node we might see here that falls into
+ * that category is Append.
+ */
+ if (IsA(result_plan, Append))
+ {
+ result_plan = (Plan *) make_result(sub_tlist, NULL,
+ result_plan);
+ }
+ else
+ {
+ /*
+ * Otherwise, just replace the subplan's flat tlist with
+ * the desired tlist.
+ */
+ result_plan->targetlist = sub_tlist;
+ }
+ /*
+ * 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.
+ */
+ cost_qual_eval(&tlist_cost, sub_tlist);
+ result_plan->startup_cost += tlist_cost.startup;
+ result_plan->total_cost += tlist_cost.startup +
+ tlist_cost.per_tuple * result_plan->plan_rows;
}
else
{
/*
- * Otherwise, just replace the flat tlist with the desired tlist.
+ * Since we're using query_planner's tlist and not the one
+ * make_subplanTargetList calculated, we have to refigure
+ * any grouping-column indexes make_subplanTargetList computed.
*/
- result_plan->targetlist = sub_tlist;
+ locate_grouping_columns(parse, tlist, result_plan->targetlist,
+ groupColIdx);
}
/*
if (parse->sortClause)
{
if (!pathkeys_contained_in(sort_pathkeys, current_pathkeys))
- result_plan = make_sortplan(parse, tlist, result_plan,
- parse->sortClause);
+ {
+ result_plan = (Plan *) make_sort_from_sortclauses(parse,
+ tlist,
+ result_plan,
+ parse->sortClause);
+ current_pathkeys = sort_pathkeys;
+ }
}
/*
* comparable to GROUP BY.
*/
if (!parse->groupClause && !parse->hasAggs)
+ {
+ List *distinctExprs;
+
+ distinctExprs = get_sortgrouplist_exprs(parse->distinctClause,
+ parse->targetList);
result_plan->plan_rows = estimate_num_groups(parse,
- parse->distinctClause,
+ distinctExprs,
result_plan->plan_rows);
+ }
}
/*
parse->limitCount);
}
+ /*
+ * Return the actual output ordering in query_pathkeys for possible
+ * use by an outer query level.
+ */
+ parse->query_pathkeys = current_pathkeys;
+
return result_plan;
}
* the extra computation to recompute a+b at the outer level; see
* replace_vars_with_subplan_refs() in setrefs.c.)
*
+ * 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.
+ *
* 'parse' is the query being processed.
* '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 subplan's target list.
+ * 'need_tlist_eval' is set true if we really need to evaluate the
+ * result tlist.
*
* The result is the targetlist to be passed to the subplan.
*---------------
static List *
make_subplanTargetList(Query *parse,
List *tlist,
- AttrNumber **groupColIdx)
+ AttrNumber **groupColIdx,
+ bool *need_tlist_eval)
{
List *sub_tlist;
List *extravars;
* query_planner should receive the unmodified target list.
*/
if (!parse->hasAggs && !parse->groupClause && !parse->havingQual)
+ {
+ *need_tlist_eval = true;
return tlist;
+ }
/*
* Otherwise, start with a "flattened" tlist (having just the vars
extravars = pull_var_clause(parse->havingQual, false);
sub_tlist = add_to_flat_tlist(sub_tlist, extravars);
freeList(extravars);
+ *need_tlist_eval = false; /* only eval if not flat tlist */
/*
* If grouping, create sub_tlist entries for all GROUP BY expressions
false),
(Expr *) groupexpr);
sub_tlist = lappend(sub_tlist, te);
+ *need_tlist_eval = true; /* it's not flat anymore */
}
/* and save its resno */
return sub_tlist;
}
+/*
+ * locate_grouping_columns
+ * Locate grouping columns in the tlist chosen by query_planner.
+ *
+ * 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.
+ */
+static void
+locate_grouping_columns(Query *parse,
+ List *tlist,
+ List *sub_tlist,
+ AttrNumber *groupColIdx)
+{
+ int keyno = 0;
+ List *gl;
+
+ /*
+ * No work unless grouping.
+ */
+ if (!parse->groupClause)
+ {
+ Assert(groupColIdx == NULL);
+ return;
+ }
+ Assert(groupColIdx != NULL);
+
+ foreach(gl, parse->groupClause)
+ {
+ GroupClause *grpcl = (GroupClause *) lfirst(gl);
+ Node *groupexpr = get_sortgroupclause_expr(grpcl, tlist);
+ TargetEntry *te = NULL;
+ List *sl;
+
+ foreach(sl, sub_tlist)
+ {
+ te = (TargetEntry *) lfirst(sl);
+ if (equal(groupexpr, te->expr))
+ break;
+ }
+ if (!sl)
+ elog(ERROR, "locate_grouping_columns: failed");
+
+ groupColIdx[keyno++] = te->resdom->resno;
+ }
+}
+
/*
* make_groupsortplan
* Add a Sort node to explicitly sort according to the GROUP BY clause.
Plan *subplan)
{
List *sort_tlist = new_unsorted_tlist(subplan->targetlist);
+ int grpno = 0;
int keyno = 0;
List *gl;
foreach(gl, groupClause)
{
GroupClause *grpcl = (GroupClause *) lfirst(gl);
- TargetEntry *te = nth(grpColIdx[keyno] - 1, sort_tlist);
+ TargetEntry *te = nth(grpColIdx[grpno] - 1, sort_tlist);
Resdom *resdom = te->resdom;
/*
resdom->reskey = ++keyno;
resdom->reskeyop = grpcl->sortop;
}
+ grpno++;
}
Assert(keyno > 0);
return (Plan *) make_sort(parse, sort_tlist, subplan, keyno);
}
-/*
- * make_sortplan
- * Add a Sort node to implement an explicit ORDER BY clause.
- */
-Plan *
-make_sortplan(Query *parse, List *tlist, Plan *plannode, List *sortcls)
-{
- List *sort_tlist;
- List *i;
- int keyno = 0;
-
- /*
- * First make a copy of the tlist so that we don't corrupt the
- * original.
- */
- sort_tlist = new_unsorted_tlist(tlist);
-
- foreach(i, sortcls)
- {
- SortClause *sortcl = (SortClause *) lfirst(i);
- TargetEntry *tle = get_sortgroupclause_tle(sortcl, sort_tlist);
- Resdom *resdom = tle->resdom;
-
- /*
- * Check for the possibility of duplicate order-by clauses --- the
- * parser should have removed 'em, but the executor will get
- * terribly confused if any get through!
- */
- if (resdom->reskey == 0)
- {
- /* OK, insert the ordering info needed by the executor. */
- resdom->reskey = ++keyno;
- resdom->reskeyop = sortcl->sortop;
- }
- }
-
- Assert(keyno > 0);
-
- return (Plan *) make_sort(parse, sort_tlist, plannode, keyno);
-}
-
/*
* postprocess_setop_tlist
* Fix up targetlist returned by plan_set_operations().
projects / postgresql / blobdiff