From c291203ca3cde3b10e7a8962df2c1ccc737a9e6f Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 8 Nov 2007 21:49:48 +0000
Subject: [PATCH] Fix EquivalenceClass code to handle volatile sort expressions
in a more predictable manner; in particular that if you say ORDER BY
output-column-ref, it will in fact sort by that specific column even if there
are multiple syntactic matches. An example is SELECT random() AS a,
random() AS b FROM ... ORDER BY b, a; While the use-case for this might be a
bit debatable, it worked as expected in earlier releases, so we should
preserve the behavior for 8.3. Per my recent proposal.
While at it, fix convert_subquery_pathkeys() to handle RelabelType stripping
in both directions; it needs this for the same reasons make_sort_from_pathkeys
does.
---
src/backend/nodes/outfuncs.c | 3 +-
src/backend/optimizer/path/equivclass.c | 14 +-
src/backend/optimizer/path/pathkeys.c | 247 +++++++++++++++---------
src/backend/optimizer/plan/createplan.c | 169 +++++++++-------
src/backend/optimizer/util/tlist.c | 33 ++--
src/include/nodes/relation.h | 8 +-
src/include/optimizer/paths.h | 5 +-
src/include/optimizer/tlist.h | 4 +-
8 files changed, 300 insertions(+), 183 deletions(-)
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 005879b8c91..fc4f7d2daca 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.315 2007/10/11 18:05:27 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.316 2007/11/08 21:49:47 tgl Exp $
*
* NOTES
* Every node type that can appear in stored rules' parsetrees *must*
@@ -1405,6 +1405,7 @@ _outEquivalenceClass(StringInfo str, EquivalenceClass *node)
WRITE_BOOL_FIELD(ec_has_volatile);
WRITE_BOOL_FIELD(ec_below_outer_join);
WRITE_BOOL_FIELD(ec_broken);
+ WRITE_UINT_FIELD(ec_sortref);
}
static void
diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index fc862438ffb..18c6ff93686 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -10,7 +10,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/optimizer/path/equivclass.c,v 1.3 2007/07/07 20:46:45 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/optimizer/path/equivclass.c,v 1.4 2007/11/08 21:49:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -294,6 +294,7 @@ process_equivalence(PlannerInfo *root, RestrictInfo *restrictinfo,
ec->ec_has_volatile = false;
ec->ec_below_outer_join = below_outer_join;
ec->ec_broken = false;
+ ec->ec_sortref = 0;
ec->ec_merged = NULL;
em1 = add_eq_member(ec, item1, item1_relids, false, item1_type);
em2 = add_eq_member(ec, item2, item2_relids, false, item2_type);
@@ -354,6 +355,9 @@ add_eq_member(EquivalenceClass *ec, Expr *expr, Relids relids,
* class it is a member of; if none, build a new single-member
* EquivalenceClass for it.
*
+ * sortref is the SortGroupRef of the originating SortClause, if any,
+ * or zero if not.
+ *
* This can be used safely both before and after EquivalenceClass merging;
* since it never causes merging it does not invalidate any existing ECs
* or PathKeys.
@@ -367,7 +371,8 @@ EquivalenceClass *
get_eclass_for_sort_expr(PlannerInfo *root,
Expr *expr,
Oid expr_datatype,
- List *opfamilies)
+ List *opfamilies,
+ Index sortref)
{
EquivalenceClass *newec;
EquivalenceMember *newem;
@@ -382,7 +387,9 @@ get_eclass_for_sort_expr(PlannerInfo *root,
EquivalenceClass *cur_ec = (EquivalenceClass *) lfirst(lc1);
ListCell *lc2;
- /* we allow matching to a volatile EC here */
+ /* Never match to a volatile EC */
+ if (cur_ec->ec_has_volatile)
+ continue;
if (!equal(opfamilies, cur_ec->ec_opfamilies))
continue;
@@ -423,6 +430,7 @@ get_eclass_for_sort_expr(PlannerInfo *root,
newec->ec_has_volatile = contain_volatile_functions((Node *) expr);
newec->ec_below_outer_join = false;
newec->ec_broken = false;
+ newec->ec_sortref = sortref;
newec->ec_merged = NULL;
newem = add_eq_member(newec, expr, pull_varnos((Node *) expr),
false, expr_datatype);
diff --git a/src/backend/optimizer/path/pathkeys.c b/src/backend/optimizer/path/pathkeys.c
index f96d7bb5554..846fe78ee6c 100644
--- a/src/backend/optimizer/path/pathkeys.c
+++ b/src/backend/optimizer/path/pathkeys.c
@@ -11,7 +11,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.88 2007/11/08 19:25:37 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/optimizer/path/pathkeys.c,v 1.89 2007/11/08 21:49:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -46,6 +46,7 @@ static bool pathkey_is_redundant(PathKey *new_pathkey, List *pathkeys);
static PathKey *make_pathkey_from_sortinfo(PlannerInfo *root,
Expr *expr, Oid ordering_op,
bool nulls_first,
+ Index sortref,
bool canonicalize);
static Var *find_indexkey_var(PlannerInfo *root, RelOptInfo *rel,
AttrNumber varattno);
@@ -233,6 +234,9 @@ canonicalize_pathkeys(PlannerInfo *root, List *pathkeys)
* a PathKey. If canonicalize = true, the result is a "canonical"
* PathKey, otherwise not. (But note it might be redundant anyway.)
*
+ * If the PathKey is being generated from a SortClause, sortref should be
+ * the SortClause's SortGroupRef; otherwise zero.
+ *
* canonicalize should always be TRUE after EquivalenceClass merging has
* been performed, but FALSE if we haven't done EquivalenceClass merging yet.
*/
@@ -240,6 +244,7 @@ static PathKey *
make_pathkey_from_sortinfo(PlannerInfo *root,
Expr *expr, Oid ordering_op,
bool nulls_first,
+ Index sortref,
bool canonicalize)
{
Oid opfamily,
@@ -303,7 +308,8 @@ make_pathkey_from_sortinfo(PlannerInfo *root,
}
/* Now find or create a matching EquivalenceClass */
- eclass = get_eclass_for_sort_expr(root, expr, opcintype, opfamilies);
+ eclass = get_eclass_for_sort_expr(root, expr, opcintype, opfamilies,
+ sortref);
/* And finally we can find or create a PathKey node */
if (canonicalize)
@@ -525,6 +531,7 @@ build_index_pathkeys(PlannerInfo *root,
indexkey,
sortop,
nulls_first,
+ 0,
true);
/* Add to list unless redundant */
@@ -597,102 +604,161 @@ convert_subquery_pathkeys(PlannerInfo *root, RelOptInfo *rel,
PathKey *sub_pathkey = (PathKey *) lfirst(i);
EquivalenceClass *sub_eclass = sub_pathkey->pk_eclass;
PathKey *best_pathkey = NULL;
- int best_score = -1;
- ListCell *j;
- /*
- * The sub_pathkey's EquivalenceClass could contain multiple elements
- * (representing knowledge that multiple items are effectively equal).
- * Each element might match none, one, or more of the output columns
- * that are visible to the outer query. This means we may have
- * multiple possible representations of the sub_pathkey in the context
- * of the outer query. Ideally we would generate them all and put
- * them all into an EC of the outer query, thereby propagating
- * equality knowledge up to the outer query. Right now we cannot do
- * so, because the outer query's EquivalenceClasses are already frozen
- * when this is called. Instead we prefer the one that has the highest
- * "score" (number of EC peers, plus one if it matches the outer
- * query_pathkeys). This is the most likely to be useful in the outer
- * query.
- */
- foreach(j, sub_eclass->ec_members)
+ if (sub_eclass->ec_has_volatile)
{
- EquivalenceMember *sub_member = (EquivalenceMember *) lfirst(j);
- Expr *sub_expr = sub_member->em_expr;
- Expr *rtarg;
- ListCell *k;
-
/*
- * We handle two cases: the sub_pathkey key can be either an exact
- * match for a targetlist entry, or a RelabelType of a targetlist
- * entry. (The latter case is worth extra code because it arises
- * frequently in connection with varchar fields.)
+ * If the sub_pathkey's EquivalenceClass is volatile, then it must
+ * have come from an ORDER BY clause, and we have to match it to
+ * that same targetlist entry.
*/
- if (IsA(sub_expr, RelabelType))
- rtarg = ((RelabelType *) sub_expr)->arg;
- else
- rtarg = NULL;
-
- foreach(k, sub_tlist)
+ TargetEntry *tle;
+
+ if (sub_eclass->ec_sortref == 0) /* can't happen */
+ elog(ERROR, "volatile EquivalenceClass has no sortref");
+ tle = get_sortgroupref_tle(sub_eclass->ec_sortref, sub_tlist);
+ Assert(tle);
+ /* resjunk items aren't visible to outer query */
+ if (!tle->resjunk)
{
- TargetEntry *tle = (TargetEntry *) lfirst(k);
+ /* We can represent this sub_pathkey */
+ EquivalenceMember *sub_member;
Expr *outer_expr;
EquivalenceClass *outer_ec;
- PathKey *outer_pk;
- int score;
- /* resjunk items aren't visible to outer query */
- if (tle->resjunk)
- continue;
+ Assert(list_length(sub_eclass->ec_members) == 1);
+ sub_member = (EquivalenceMember *) linitial(sub_eclass->ec_members);
+ outer_expr = (Expr *)
+ makeVar(rel->relid,
+ tle->resno,
+ exprType((Node *) tle->expr),
+ exprTypmod((Node *) tle->expr),
+ 0);
+ outer_ec =
+ get_eclass_for_sort_expr(root,
+ outer_expr,
+ sub_member->em_datatype,
+ sub_eclass->ec_opfamilies,
+ 0);
+ best_pathkey =
+ make_canonical_pathkey(root,
+ outer_ec,
+ sub_pathkey->pk_opfamily,
+ sub_pathkey->pk_strategy,
+ sub_pathkey->pk_nulls_first);
+ }
+ }
+ else
+ {
+ /*
+ * Otherwise, the sub_pathkey's EquivalenceClass could contain
+ * multiple elements (representing knowledge that multiple items
+ * are effectively equal). Each element might match none, one, or
+ * more of the output columns that are visible to the outer
+ * query. This means we may have multiple possible representations
+ * of the sub_pathkey in the context of the outer query. Ideally
+ * we would generate them all and put them all into an EC of the
+ * outer query, thereby propagating equality knowledge up to the
+ * outer query. Right now we cannot do so, because the outer
+ * query's EquivalenceClasses are already frozen when this is
+ * called. Instead we prefer the one that has the highest "score"
+ * (number of EC peers, plus one if it matches the outer
+ * query_pathkeys). This is the most likely to be useful in the
+ * outer query.
+ */
+ int best_score = -1;
+ ListCell *j;
- if (equal(tle->expr, sub_expr))
- {
- /* Exact match */
- outer_expr = (Expr *)
- makeVar(rel->relid,
- tle->resno,
- exprType((Node *) tle->expr),
- exprTypmod((Node *) tle->expr),
- 0);
- }
- else if (rtarg && equal(tle->expr, rtarg))
+ foreach(j, sub_eclass->ec_members)
+ {
+ EquivalenceMember *sub_member = (EquivalenceMember *) lfirst(j);
+ Expr *sub_expr = sub_member->em_expr;
+ Expr *sub_stripped;
+ ListCell *k;
+
+ /*
+ * We handle two cases: the sub_pathkey key can be either an
+ * exact match for a targetlist entry, or it could match after
+ * stripping RelabelType nodes. (We need that case since
+ * make_pathkey_from_sortinfo could add or remove RelabelType.)
+ */
+ sub_stripped = sub_expr;
+ while (sub_stripped && IsA(sub_stripped, RelabelType))
+ sub_stripped = ((RelabelType *) sub_stripped)->arg;
+
+ foreach(k, sub_tlist)
{
- /* Match after discarding RelabelType */
- outer_expr = (Expr *)
- makeVar(rel->relid,
- tle->resno,
- exprType((Node *) tle->expr),
- exprTypmod((Node *) tle->expr),
- 0);
- outer_expr = (Expr *)
- makeRelabelType((Expr *) outer_expr,
- ((RelabelType *) sub_expr)->resulttype,
- ((RelabelType *) sub_expr)->resulttypmod,
- ((RelabelType *) sub_expr)->relabelformat);
- }
- else
- continue;
+ TargetEntry *tle = (TargetEntry *) lfirst(k);
+ Expr *outer_expr;
+ EquivalenceClass *outer_ec;
+ PathKey *outer_pk;
+ int score;
- /* Found a representation for this sub_pathkey */
- outer_ec = get_eclass_for_sort_expr(root,
- outer_expr,
- sub_member->em_datatype,
- sub_eclass->ec_opfamilies);
- outer_pk = make_canonical_pathkey(root,
- outer_ec,
- sub_pathkey->pk_opfamily,
- sub_pathkey->pk_strategy,
- sub_pathkey->pk_nulls_first);
- /* score = # of equivalence peers */
- score = list_length(outer_ec->ec_members) - 1;
- /* +1 if it matches the proper query_pathkeys item */
- if (retvallen < outer_query_keys &&
- list_nth(root->query_pathkeys, retvallen) == outer_pk)
- score++;
- if (score > best_score)
- {
- best_pathkey = outer_pk;
- best_score = score;
+ /* resjunk items aren't visible to outer query */
+ if (tle->resjunk)
+ continue;
+
+ if (equal(tle->expr, sub_expr))
+ {
+ /* Exact match */
+ outer_expr = (Expr *)
+ makeVar(rel->relid,
+ tle->resno,
+ exprType((Node *) tle->expr),
+ exprTypmod((Node *) tle->expr),
+ 0);
+ }
+ else
+ {
+ Expr *tle_stripped;
+
+ tle_stripped = tle->expr;
+ while (tle_stripped && IsA(tle_stripped, RelabelType))
+ tle_stripped = ((RelabelType *) tle_stripped)->arg;
+
+ if (equal(tle_stripped, sub_stripped))
+ {
+ /* Match after discarding RelabelType */
+ outer_expr = (Expr *)
+ makeVar(rel->relid,
+ tle->resno,
+ exprType((Node *) tle->expr),
+ exprTypmod((Node *) tle->expr),
+ 0);
+ if (exprType((Node *) outer_expr) !=
+ exprType((Node *) sub_expr))
+ outer_expr = (Expr *)
+ makeRelabelType(outer_expr,
+ exprType((Node *) sub_expr),
+ -1,
+ COERCE_DONTCARE);
+ }
+ else
+ continue;
+ }
+
+ /* Found a representation for this sub_pathkey */
+ outer_ec = get_eclass_for_sort_expr(root,
+ outer_expr,
+ sub_member->em_datatype,
+ sub_eclass->ec_opfamilies,
+ 0);
+ outer_pk = make_canonical_pathkey(root,
+ outer_ec,
+ sub_pathkey->pk_opfamily,
+ sub_pathkey->pk_strategy,
+ sub_pathkey->pk_nulls_first);
+ /* score = # of equivalence peers */
+ score = list_length(outer_ec->ec_members) - 1;
+ /* +1 if it matches the proper query_pathkeys item */
+ if (retvallen < outer_query_keys &&
+ list_nth(root->query_pathkeys, retvallen) == outer_pk)
+ score++;
+ if (score > best_score)
+ {
+ best_pathkey = outer_pk;
+ best_score = score;
+ }
}
}
}
@@ -795,6 +861,7 @@ make_pathkeys_for_sortclauses(PlannerInfo *root,
sortkey,
sortcl->sortop,
sortcl->nulls_first,
+ sortcl->tleSortGroupRef,
canonicalize);
/* Canonical form eliminates redundant ordering keys */
@@ -843,12 +910,14 @@ cache_mergeclause_eclasses(PlannerInfo *root, RestrictInfo *restrictinfo)
get_eclass_for_sort_expr(root,
(Expr *) get_leftop(clause),
lefttype,
- restrictinfo->mergeopfamilies);
+ restrictinfo->mergeopfamilies,
+ 0);
restrictinfo->right_ec =
get_eclass_for_sort_expr(root,
(Expr *) get_rightop(clause),
righttype,
- restrictinfo->mergeopfamilies);
+ restrictinfo->mergeopfamilies,
+ 0);
}
else
Assert(restrictinfo->right_ec != NULL);
diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index becb8255e87..e2b46f970ce 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.233 2007/11/08 19:25:37 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.234 2007/11/08 21:49:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -2730,103 +2730,124 @@ make_sort_from_pathkeys(PlannerInfo *root, Plan *lefttree, List *pathkeys,
foreach(i, pathkeys)
{
PathKey *pathkey = (PathKey *) lfirst(i);
+ EquivalenceClass *ec = pathkey->pk_eclass;
TargetEntry *tle = NULL;
Oid pk_datatype = InvalidOid;
Oid sortop;
ListCell *j;
- /*
- * We can sort by any non-constant expression listed in the pathkey's
- * EquivalenceClass. For now, we take the first one that corresponds
- * to an available item in the tlist. If there isn't any, use the first
- * one that is an expression in the input's vars. (The non-const
- * restriction only matters if the EC is below_outer_join; but if it
- * isn't, it won't contain consts anyway, else we'd have discarded
- * the pathkey as redundant.)
- *
- * XXX if we have a choice, is there any way of figuring out which
- * might be cheapest to execute? (For example, int4lt is likely much
- * cheaper to execute than numericlt, but both might appear in the
- * same equivalence class...) Not clear that we ever will have an
- * interesting choice in practice, so it may not matter.
- */
- foreach(j, pathkey->pk_eclass->ec_members)
+ if (ec->ec_has_volatile)
{
- EquivalenceMember *em = (EquivalenceMember *) lfirst(j);
-
- if (em->em_is_const || em->em_is_child)
- continue;
-
- tle = tlist_member((Node *) em->em_expr, tlist);
- if (tle)
- {
- pk_datatype = em->em_datatype;
- break; /* found expr already in tlist */
- }
-
/*
- * We can also use it if the pathkey expression is a relabel
- * of the tlist entry, or vice versa. This is needed for
- * binary-compatible cases (cf. make_pathkey_from_sortinfo).
- * We prefer an exact match, though, so we do the basic
- * search first.
+ * If the pathkey's EquivalenceClass is volatile, then it must
+ * have come from an ORDER BY clause, and we have to match it to
+ * that same targetlist entry.
*/
- tle = tlist_member_ignore_relabel((Node *) em->em_expr, tlist);
- if (tle)
- {
- pk_datatype = em->em_datatype;
- break; /* found expr already in tlist */
- }
+ if (ec->ec_sortref == 0) /* can't happen */
+ elog(ERROR, "volatile EquivalenceClass has no sortref");
+ tle = get_sortgroupref_tle(ec->ec_sortref, tlist);
+ Assert(tle);
+ Assert(list_length(ec->ec_members) == 1);
+ pk_datatype = ((EquivalenceMember *) linitial(ec->ec_members))->em_datatype;
}
- if (!tle)
+ else
{
- /* No matching tlist item; look for a computable expression */
- Expr *sortexpr = NULL;
-
- foreach(j, pathkey->pk_eclass->ec_members)
+ /*
+ * Otherwise, we can sort by any non-constant expression listed in
+ * the pathkey's EquivalenceClass. For now, we take the first one
+ * that corresponds to an available item in the tlist. If there
+ * isn't any, use the first one that is an expression in the
+ * input's vars. (The non-const restriction only matters if the
+ * EC is below_outer_join; but if it isn't, it won't contain
+ * consts anyway, else we'd have discarded the pathkey as
+ * redundant.)
+ *
+ * XXX if we have a choice, is there any way of figuring out which
+ * might be cheapest to execute? (For example, int4lt is likely
+ * much cheaper to execute than numericlt, but both might appear
+ * in the same equivalence class...) Not clear that we ever will
+ * have an interesting choice in practice, so it may not matter.
+ */
+ foreach(j, ec->ec_members)
{
EquivalenceMember *em = (EquivalenceMember *) lfirst(j);
- List *exprvars;
- ListCell *k;
if (em->em_is_const || em->em_is_child)
continue;
- sortexpr = em->em_expr;
- exprvars = pull_var_clause((Node *) sortexpr, false);
- foreach(k, exprvars)
+
+ tle = tlist_member((Node *) em->em_expr, tlist);
+ if (tle)
{
- if (!tlist_member_ignore_relabel(lfirst(k), tlist))
- break;
+ pk_datatype = em->em_datatype;
+ break; /* found expr already in tlist */
}
- list_free(exprvars);
- if (!k)
+
+ /*
+ * We can also use it if the pathkey expression is a relabel
+ * of the tlist entry, or vice versa. This is needed for
+ * binary-compatible cases (cf. make_pathkey_from_sortinfo).
+ * We prefer an exact match, though, so we do the basic
+ * search first.
+ */
+ tle = tlist_member_ignore_relabel((Node *) em->em_expr, tlist);
+ if (tle)
{
pk_datatype = em->em_datatype;
- break; /* found usable expression */
+ break; /* found expr already in tlist */
}
}
- if (!j)
- elog(ERROR, "could not find pathkey item to sort");
- /*
- * Do we need to insert a Result node?
- */
- if (!is_projection_capable_plan(lefttree))
+ if (!tle)
{
- /* copy needed so we don't modify input's tlist below */
- tlist = copyObject(tlist);
- lefttree = (Plan *) make_result(root, tlist, NULL, lefttree);
- }
+ /* No matching tlist item; look for a computable expression */
+ Expr *sortexpr = NULL;
- /*
- * Add resjunk entry to input's tlist
- */
- tle = makeTargetEntry(sortexpr,
- list_length(tlist) + 1,
- NULL,
- true);
- tlist = lappend(tlist, tle);
- lefttree->targetlist = tlist; /* just in case NIL before */
+ foreach(j, ec->ec_members)
+ {
+ EquivalenceMember *em = (EquivalenceMember *) lfirst(j);
+ List *exprvars;
+ ListCell *k;
+
+ if (em->em_is_const || em->em_is_child)
+ continue;
+ sortexpr = em->em_expr;
+ exprvars = pull_var_clause((Node *) sortexpr, false);
+ foreach(k, exprvars)
+ {
+ if (!tlist_member_ignore_relabel(lfirst(k), tlist))
+ break;
+ }
+ list_free(exprvars);
+ if (!k)
+ {
+ pk_datatype = em->em_datatype;
+ break; /* found usable expression */
+ }
+ }
+ if (!j)
+ elog(ERROR, "could not find pathkey item to sort");
+
+ /*
+ * Do we need to insert a Result node?
+ */
+ if (!is_projection_capable_plan(lefttree))
+ {
+ /* copy needed so we don't modify input's tlist below */
+ tlist = copyObject(tlist);
+ lefttree = (Plan *) make_result(root, tlist, NULL,
+ lefttree);
+ }
+
+ /*
+ * Add resjunk entry to input's tlist
+ */
+ tle = makeTargetEntry(sortexpr,
+ list_length(tlist) + 1,
+ NULL,
+ true);
+ tlist = lappend(tlist, tle);
+ lefttree->targetlist = tlist; /* just in case NIL before */
+ }
}
/*
diff --git a/src/backend/optimizer/util/tlist.c b/src/backend/optimizer/util/tlist.c
index e58fe7dc7f1..d2ac14cfa1b 100644
--- a/src/backend/optimizer/util/tlist.c
+++ b/src/backend/optimizer/util/tlist.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/optimizer/util/tlist.c,v 1.75 2007/11/08 19:25:37 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/optimizer/util/tlist.c,v 1.76 2007/11/08 21:49:47 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -131,26 +131,22 @@ add_to_flat_tlist(List *tlist, List *vars)
return tlist;
}
+
/*
- * get_sortgroupclause_tle
- * Find the targetlist entry matching the given SortClause
- * (or GroupClause) by ressortgroupref, and return it.
- *
- * Because GroupClause is typedef'd as SortClause, either kind of
- * node can be passed without casting.
+ * get_sortgroupref_tle
+ * Find the targetlist entry matching the given SortGroupRef index,
+ * and return it.
*/
TargetEntry *
-get_sortgroupclause_tle(SortClause *sortClause,
- List *targetList)
+get_sortgroupref_tle(Index sortref, List *targetList)
{
- Index refnumber = sortClause->tleSortGroupRef;
ListCell *l;
foreach(l, targetList)
{
TargetEntry *tle = (TargetEntry *) lfirst(l);
- if (tle->ressortgroupref == refnumber)
+ if (tle->ressortgroupref == sortref)
return tle;
}
@@ -158,6 +154,21 @@ get_sortgroupclause_tle(SortClause *sortClause,
return NULL; /* keep compiler quiet */
}
+/*
+ * get_sortgroupclause_tle
+ * Find the targetlist entry matching the given SortClause
+ * (or GroupClause) by ressortgroupref, and return it.
+ *
+ * Because GroupClause is typedef'd as SortClause, either kind of
+ * node can be passed without casting.
+ */
+TargetEntry *
+get_sortgroupclause_tle(SortClause *sortClause,
+ List *targetList)
+{
+ return get_sortgroupref_tle(sortClause->tleSortGroupRef, targetList);
+}
+
/*
* get_sortgroupclause_expr
* Find the targetlist entry matching the given SortClause
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index 38903520222..db6eef20964 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.147 2007/10/11 18:05:27 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.148 2007/11/08 21:49:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -449,7 +449,10 @@ typedef struct IndexOptInfo
* which is a case that can't arise otherwise since clauses containing
* volatile functions are never considered mergejoinable. We mark such
* EquivalenceClasses specially to prevent them from being merged with
- * ordinary EquivalenceClasses.
+ * ordinary EquivalenceClasses. Also, for volatile expressions we have
+ * to be careful to match the EquivalenceClass to the correct targetlist
+ * entry: consider SELECT random() AS a, random() AS b ... ORDER BY b,a.
+ * So we record the SortGroupRef of the originating sort clause.
*
* We allow equality clauses appearing below the nullable side of an outer join
* to form EquivalenceClasses, but these have a slightly different meaning:
@@ -472,6 +475,7 @@ typedef struct EquivalenceClass
bool ec_has_volatile; /* the (sole) member is a volatile expr */
bool ec_below_outer_join; /* equivalence applies below an OJ */
bool ec_broken; /* failed to generate needed clauses? */
+ Index ec_sortref; /* originating sortclause label, or 0 */
struct EquivalenceClass *ec_merged; /* set if merged into another EC */
} EquivalenceClass;
diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h
index cbde0c7b9a5..cf589b48af7 100644
--- a/src/include/optimizer/paths.h
+++ b/src/include/optimizer/paths.h
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/optimizer/paths.h,v 1.99 2007/09/26 18:51:51 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/paths.h,v 1.100 2007/11/08 21:49:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -115,7 +115,8 @@ extern void reconsider_outer_join_clauses(PlannerInfo *root);
extern EquivalenceClass *get_eclass_for_sort_expr(PlannerInfo *root,
Expr *expr,
Oid expr_datatype,
- List *opfamilies);
+ List *opfamilies,
+ Index sortref);
extern void generate_base_implied_equalities(PlannerInfo *root);
extern List *generate_join_implied_equalities(PlannerInfo *root,
RelOptInfo *joinrel,
diff --git a/src/include/optimizer/tlist.h b/src/include/optimizer/tlist.h
index bb127cbce2b..515339363ab 100644
--- a/src/include/optimizer/tlist.h
+++ b/src/include/optimizer/tlist.h
@@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
- * $PostgreSQL: pgsql/src/include/optimizer/tlist.h,v 1.46 2007/11/08 19:25:37 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/tlist.h,v 1.47 2007/11/08 21:49:48 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -23,6 +23,8 @@ extern TargetEntry *tlist_member_ignore_relabel(Node *node, List *targetlist);
extern List *flatten_tlist(List *tlist);
extern List *add_to_flat_tlist(List *tlist, List *vars);
+extern TargetEntry *get_sortgroupref_tle(Index sortref,
+ List *targetList);
extern TargetEntry *get_sortgroupclause_tle(SortClause *sortClause,
List *targetList);
extern Node *get_sortgroupclause_expr(SortClause *sortClause,
--
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