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Get rid of the rather fuzzily defined FlattenedSubLink node type in favor of

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making pull_up_sublinks() construct a full-blown JoinExpr tree representation
of IN/EXISTS SubLinks that it is able to convert to semi or anti joins.
This makes pull_up_sublinks() a shade more complex, but the gain in semantic
clarity is worth it.  I still have more to do in this area to address the
previously-discussed problems, but this commit in itself fixes at least one
bug in HEAD, as shown by added regression test case.
This commit is contained in:
Tom Lane
2009-02-25 03:30:38 +00:00
parent 7380b6384b
commit e549722a8b
18 changed files with 298 additions and 496 deletions
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110
src/backend/optimizer/plan/initsplan.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/plan/initsplan.c,v 1.147 2009/02/20 00:01:03 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/plan/initsplan.c,v 1.148 2009/02/25 03:30:37 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -52,9 +52,6 @@ static void distribute_qual_to_rels(PlannerInfo *root, Node *clause,
Relids qualscope,
Relids ojscope,
Relids outerjoin_nonnullable);
static void distribute_sublink_quals_to_rels(PlannerInfo *root,
FlattenedSubLink *fslink,
bool below_outer_join);
static bool check_outerjoin_delay(PlannerInfo *root, Relids *relids_p,
bool is_pushed_down);
static bool check_redundant_nullability_qual(PlannerInfo *root, Node *clause);
@@ -336,15 +333,9 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
{
Node *qual = (Node *) lfirst(l);
/* FlattenedSubLink wrappers need special processing */
if (qual && IsA(qual, FlattenedSubLink))
distribute_sublink_quals_to_rels(root,
(FlattenedSubLink *) qual,
below_outer_join);
else
distribute_qual_to_rels(root, qual,
false, below_outer_join, JOIN_INNER,
*qualscope, NULL, NULL);
distribute_qual_to_rels(root, qual,
false, below_outer_join, JOIN_INNER,
*qualscope, NULL, NULL);
}
}
else if (IsA(jtnode, JoinExpr))
@@ -399,6 +390,18 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
*inner_join_rels = bms_union(left_inners, right_inners);
nonnullable_rels = leftids;
break;
case JOIN_SEMI:
leftjoinlist = deconstruct_recurse(root, j->larg,
below_outer_join,
&leftids, &left_inners);
rightjoinlist = deconstruct_recurse(root, j->rarg,
below_outer_join,
&rightids, &right_inners);
*qualscope = bms_union(leftids, rightids);
*inner_join_rels = bms_union(left_inners, right_inners);
/* Semi join adds no restrictions for quals */
nonnullable_rels = NULL;
break;
case JOIN_FULL:
leftjoinlist = deconstruct_recurse(root, j->larg,
true,
@@ -425,6 +428,9 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
* semantic scope (ojscope) to pass to distribute_qual_to_rels. But
* we mustn't add it to join_info_list just yet, because we don't want
* distribute_qual_to_rels to think it is an outer join below us.
*
* Semijoins are a bit of a hybrid: we build a SpecialJoinInfo,
* but we want ojscope = NULL for distribute_qual_to_rels.
*/
if (j->jointype != JOIN_INNER)
{
@@ -433,7 +439,11 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
*inner_join_rels,
j->jointype,
(List *) j->quals);
ojscope = bms_union(sjinfo->min_lefthand, sjinfo->min_righthand);
if (j->jointype == JOIN_SEMI)
ojscope = NULL;
else
ojscope = bms_union(sjinfo->min_lefthand,
sjinfo->min_righthand);
}
else
{
@@ -446,16 +456,10 @@ deconstruct_recurse(PlannerInfo *root, Node *jtnode, bool below_outer_join,
{
Node *qual = (Node *) lfirst(l);
/* FlattenedSubLink wrappers need special processing */
if (qual && IsA(qual, FlattenedSubLink))
distribute_sublink_quals_to_rels(root,
(FlattenedSubLink *) qual,
below_outer_join);
else
distribute_qual_to_rels(root, qual,
false, below_outer_join, j->jointype,
*qualscope,
ojscope, nonnullable_rels);
distribute_qual_to_rels(root, qual,
false, below_outer_join, j->jointype,
*qualscope,
ojscope, nonnullable_rels);
}
/* Now we can add the SpecialJoinInfo to join_info_list */
@@ -1044,64 +1048,6 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
distribute_restrictinfo_to_rels(root, restrictinfo);
}
/*
* distribute_sublink_quals_to_rels
* Pull sublink quals out of a FlattenedSubLink node and distribute
* them appropriately; then add a SpecialJoinInfo node to the query's
* join_info_list. The FlattenedSubLink node itself is no longer
* needed and does not propagate into further processing.
*/
static void
distribute_sublink_quals_to_rels(PlannerInfo *root,
FlattenedSubLink *fslink,
bool below_outer_join)
{
List *quals = make_ands_implicit(fslink->quals);
SpecialJoinInfo *sjinfo;
Relids qualscope;
Relids ojscope;
Relids outerjoin_nonnullable;
ListCell *l;
/*
* Build a suitable SpecialJoinInfo for the sublink. Note: using
* righthand as inner_join_rels is the conservative worst case;
* it might be possible to use a smaller set and thereby allow
* the sublink join to commute with others inside its RHS.
*/
sjinfo = make_outerjoininfo(root,
fslink->lefthand, fslink->righthand,
fslink->righthand,
fslink->jointype,
quals);
/* Treat as inner join if SEMI, outer join if ANTI */
qualscope = bms_union(sjinfo->syn_lefthand, sjinfo->syn_righthand);
if (fslink->jointype == JOIN_SEMI)
{
ojscope = outerjoin_nonnullable = NULL;
}
else
{
Assert(fslink->jointype == JOIN_ANTI);
ojscope = bms_union(sjinfo->min_lefthand, sjinfo->min_righthand);
outerjoin_nonnullable = fslink->lefthand;
}
/* Distribute the join quals much as for a regular JOIN node */
foreach(l, quals)
{
Node *qual = (Node *) lfirst(l);
distribute_qual_to_rels(root, qual,
false, below_outer_join, fslink->jointype,
qualscope, ojscope, outerjoin_nonnullable);
}
/* Now we can add the SpecialJoinInfo to join_info_list */
root->join_info_list = lappend(root->join_info_list, sjinfo);
}
/*
* check_outerjoin_delay
* Detect whether a qual referencing the given relids must be delayed

168
src/backend/optimizer/plan/subselect.c
View File

@@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.145 2009/01/01 17:23:44 momjian Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.146 2009/02/25 03:30:37 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -932,12 +932,13 @@ SS_process_ctes(PlannerInfo *root)
}
/*
* convert_ANY_sublink_to_join: can we convert an ANY SubLink to a join?
* convert_ANY_sublink_to_join: try to convert an ANY SubLink to a join
*
* The caller has found an ANY SubLink at the top level of one of the query's
* qual clauses, but has not checked the properties of the SubLink further.
* Decide whether it is appropriate to process this SubLink in join style.
* Return TRUE if so, FALSE if the SubLink cannot be converted.
* If so, form a JoinExpr and return it. Return NULL if the SubLink cannot
* be converted to a join.
*
* The only non-obvious input parameter is available_rels: this is the set
* of query rels that can safely be referenced in the sublink expression.
@@ -945,30 +946,33 @@ SS_process_ctes(PlannerInfo *root)
* is present in an outer join's ON qual.) The conversion must fail if
* the converted qual would reference any but these parent-query relids.
*
* On success, two output parameters are returned:
* *new_qual is set to the qual tree that should replace the SubLink in
* the parent query's qual tree. The qual clauses are wrapped in a
* FlattenedSubLink node to help later processing place them properly.
* *fromlist is set to a list of pulled-up jointree item(s) that must be
* added at the proper spot in the parent query's jointree.
* On success, the returned JoinExpr has larg = NULL and rarg = the jointree
* item representing the pulled-up subquery. The caller must set larg to
* represent the relation(s) on the lefthand side of the new join, and insert
* the JoinExpr into the upper query's jointree at an appropriate place
* (typically, where the lefthand relation(s) had been). Note that the
* passed-in SubLink must also be removed from its original position in the
* query quals, since the quals of the returned JoinExpr replace it.
* (Notionally, we replace the SubLink with a constant TRUE, then elide the
* redundant constant from the qual.)
*
* Side effects of a successful conversion include adding the SubLink's
* subselect to the query's rangetable.
* subselect to the query's rangetable, so that it can be referenced in
* the JoinExpr's rarg.
*/
bool
JoinExpr *
convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
Relids available_rels,
Node **new_qual, List **fromlist)
Relids available_rels)
{
JoinExpr *result;
Query *parse = root->parse;
Query *subselect = (Query *) sublink->subselect;
Relids left_varnos;
Relids upper_varnos;
int rtindex;
RangeTblEntry *rte;
RangeTblRef *rtr;
List *subquery_vars;
Expr *quals;
FlattenedSubLink *fslink;
Node *quals;
Assert(sublink->subLinkType == ANY_SUBLINK);
@@ -977,28 +981,28 @@ convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
* higher levels should be okay, though.)
*/
if (contain_vars_of_level((Node *) subselect, 1))
return false;
return NULL;
/*
* The test expression must contain some Vars of the current query,
* The test expression must contain some Vars of the parent query,
* else it's not gonna be a join. (Note that it won't have Vars
* referring to the subquery, rather Params.)
*/
left_varnos = pull_varnos(sublink->testexpr);
if (bms_is_empty(left_varnos))
return false;
upper_varnos = pull_varnos(sublink->testexpr);
if (bms_is_empty(upper_varnos))
return NULL;
/*
* However, it can't refer to anything outside available_rels.
*/
if (!bms_is_subset(left_varnos, available_rels))
return false;
if (!bms_is_subset(upper_varnos, available_rels))
return NULL;
/*
* The combining operators and left-hand expressions mustn't be volatile.
*/
if (contain_volatile_functions(sublink->testexpr))
return false;
return NULL;
/*
* Okay, pull up the sub-select into upper range table.
@@ -1016,13 +1020,10 @@ convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
rtindex = list_length(parse->rtable);
/*
* Form a RangeTblRef for the pulled-up sub-select. This must be added
* to the upper jointree, but it is caller's responsibility to figure
* out where.
* Form a RangeTblRef for the pulled-up sub-select.
*/
rtr = makeNode(RangeTblRef);
rtr->rtindex = rtindex;
*fromlist = list_make1(rtr);
/*
* Build a list of Vars representing the subselect outputs.
@@ -1032,53 +1033,45 @@ convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
rtindex);
/*
* Build the replacement qual expression, replacing Params with these Vars.
* Build the new join's qual expression, replacing Params with these Vars.
*/
quals = (Expr *) convert_testexpr(root,
sublink->testexpr,
subquery_vars);
quals = convert_testexpr(root, sublink->testexpr, subquery_vars);
/*
* And finally, build the FlattenedSubLink node.
*
* Note: at this point left_varnos may well contain join relids, since
* the testexpr hasn't been run through flatten_join_alias_vars. This
* will get fixed when flatten_join_alias_vars is run.
* And finally, build the JoinExpr node.
*/
fslink = makeNode(FlattenedSubLink);
fslink->jointype = JOIN_SEMI;
fslink->lefthand = left_varnos;
fslink->righthand = bms_make_singleton(rtindex);
fslink->quals = quals;
result = makeNode(JoinExpr);
result->jointype = JOIN_SEMI;
result->isNatural = false;
result->larg = NULL; /* caller must fill this in */
result->rarg = (Node *) rtr;
result->using = NIL;
result->quals = quals;
result->alias = NULL;
result->rtindex = 0; /* we don't need an RTE for it */
*new_qual = (Node *) fslink;
return true;
return result;
}
/*
* convert_EXISTS_sublink_to_join: can we convert an EXISTS SubLink to a join?
* convert_EXISTS_sublink_to_join: try to convert an EXISTS SubLink to a join
*
* The API of this function is identical to convert_ANY_sublink_to_join's,
* except that we also support the case where the caller has found NOT EXISTS,
* so we need an additional input parameter "under_not".
*/
bool
JoinExpr *
convert_EXISTS_sublink_to_join(PlannerInfo *root, SubLink *sublink,
bool under_not,
Relids available_rels,
Node **new_qual, List **fromlist)
bool under_not, Relids available_rels)
{
JoinExpr *result;
Query *parse = root->parse;
Query *subselect = (Query *) sublink->subselect;
Node *whereClause;
int rtoffset;
int varno;
Relids clause_varnos;
Relids left_varnos;
Relids right_varnos;
Relids subselect_varnos;
FlattenedSubLink *fslink;
Relids upper_varnos;
Assert(sublink->subLinkType == EXISTS_SUBLINK);
@@ -1095,13 +1088,13 @@ convert_EXISTS_sublink_to_join(PlannerInfo *root, SubLink *sublink,
* us with noplace to evaluate the targetlist.
*/
if (!simplify_EXISTS_query(subselect))
return false;
return NULL;
/*
* The subquery must have a nonempty jointree, else we won't have a join.
*/
if (subselect->jointree->fromlist == NIL)
return false;
return NULL;
/*
* Separate out the WHERE clause. (We could theoretically also remove
@@ -1116,20 +1109,20 @@ convert_EXISTS_sublink_to_join(PlannerInfo *root, SubLink *sublink,
* query. (Vars of higher levels should be okay, though.)
*/
if (contain_vars_of_level((Node *) subselect, 1))
return false;
return NULL;
/*
* On the other hand, the WHERE clause must contain some Vars of the
* parent query, else it's not gonna be a join.
*/
if (!contain_vars_of_level(whereClause, 1))
return false;
return NULL;
/*
* We don't risk optimizing if the WHERE clause is volatile, either.
*/
if (contain_volatile_functions(whereClause))
return false;
return NULL;
/*
* Prepare to pull up the sub-select into top range table.
@@ -1142,7 +1135,7 @@ convert_EXISTS_sublink_to_join(PlannerInfo *root, SubLink *sublink,
* to do. The machinations of simplify_EXISTS_query ensured that there
* is nothing interesting in the subquery except an rtable and jointree,
* and even the jointree FromExpr no longer has quals. So we can just
* append the rtable to our own and attach the fromlist to our own.
* append the rtable to our own and use the FromExpr in our jointree.
* But first, adjust all level-zero varnos in the subquery to account
* for the rtable merger.
*/
@@ -1161,58 +1154,47 @@ convert_EXISTS_sublink_to_join(PlannerInfo *root, SubLink *sublink,
/*
* Now that the WHERE clause is adjusted to match the parent query
* environment, we can easily identify all the level-zero rels it uses.
* The ones <= rtoffset are "left rels" of the join we're forming,
* and the ones > rtoffset are "right rels".
* The ones <= rtoffset belong to the upper query; the ones > rtoffset
* do not.
*/
clause_varnos = pull_varnos(whereClause);
left_varnos = right_varnos = NULL;
upper_varnos = NULL;
while ((varno = bms_first_member(clause_varnos)) >= 0)
{
if (varno <= rtoffset)
left_varnos = bms_add_member(left_varnos, varno);
else
right_varnos = bms_add_member(right_varnos, varno);
upper_varnos = bms_add_member(upper_varnos, varno);
}
bms_free(clause_varnos);
Assert(!bms_is_empty(left_varnos));
Assert(!bms_is_empty(upper_varnos));
/*
* Now that we've got the set of upper-level varnos, we can make the
* last check: only available_rels can be referenced.
*/
if (!bms_is_subset(left_varnos, available_rels))
return false;
/* Identify all the rels syntactically within the subselect */
subselect_varnos = get_relids_in_jointree((Node *) subselect->jointree,
true);
Assert(!bms_is_empty(subselect_varnos));
Assert(bms_is_subset(right_varnos, subselect_varnos));
if (!bms_is_subset(upper_varnos, available_rels))
return NULL;
/* Now we can attach the modified subquery rtable to the parent */
parse->rtable = list_concat(parse->rtable, subselect->rtable);
/*
* Pass back the subquery fromlist to be attached to upper jointree
* in a suitable place.
* And finally, build the JoinExpr node.
*/
*fromlist = subselect->jointree->fromlist;
result = makeNode(JoinExpr);
result->jointype = under_not ? JOIN_ANTI : JOIN_SEMI;
result->isNatural = false;
result->larg = NULL; /* caller must fill this in */
/* flatten out the FromExpr node if it's useless */
if (list_length(subselect->jointree->fromlist) == 1)
result->rarg = (Node *) linitial(subselect->jointree->fromlist);
else
result->rarg = (Node *) subselect->jointree;
result->using = NIL;
result->quals = whereClause;
result->alias = NULL;
result->rtindex = 0; /* we don't need an RTE for it */
/*
* And finally, build the FlattenedSubLink node.
*
* Note: at this point left_varnos and subselect_varnos may well contain
* join relids. This will get fixed when flatten_join_alias_vars is run.
*/
fslink = makeNode(FlattenedSubLink);
fslink->jointype = under_not ? JOIN_ANTI : JOIN_SEMI;
fslink->lefthand = left_varnos;
fslink->righthand = subselect_varnos;
fslink->quals = (Expr *) whereClause;
*new_qual = (Node *) fslink;
return true;
return result;
}
/*

224
src/backend/optimizer/prep/prepjointree.c
View File

@@ -16,7 +16,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepjointree.c,v 1.62 2009/01/01 17:23:44 momjian Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepjointree.c,v 1.63 2009/02/25 03:30:37 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -44,7 +44,7 @@ typedef struct reduce_outer_joins_state
static Node *pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
Relids *relids);
static Node *pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
Relids available_rels, List **fromlist);
Relids available_rels, Node **jtlink);
static Node *pull_up_simple_subquery(PlannerInfo *root, Node *jtnode,
RangeTblEntry *rte,
bool below_outer_join,
@@ -91,7 +91,7 @@ static Node *find_jointree_node_for_rel(Node *jtnode, int relid);
* distinguish whether the ANY ought to return FALSE or NULL in cases
* involving NULL inputs. Also, in an outer join's ON clause we can only
* do this if the sublink is degenerate (ie, references only the nullable
* side of the join). In that case we can effectively push the semijoin
* side of the join). In that case it is legal to push the semijoin
* down into the nullable side of the join. If the sublink references any
* nonnullable-side variables then it would have to be evaluated as part
* of the outer join, which makes things way too complicated.
@@ -110,13 +110,22 @@ static Node *find_jointree_node_for_rel(Node *jtnode, int relid);
void
pull_up_sublinks(PlannerInfo *root)
{
Node *jtnode;
Relids relids;
/* Begin recursion through the jointree */
root->parse->jointree = (FromExpr *)
pull_up_sublinks_jointree_recurse(root,
(Node *) root->parse->jointree,
&relids);
jtnode = pull_up_sublinks_jointree_recurse(root,
(Node *) root->parse->jointree,
&relids);
/*
* root->parse->jointree must always be a FromExpr, so insert a dummy one
* if we got a bare RangeTblRef or JoinExpr out of the recursion.
*/
if (IsA(jtnode, FromExpr))
root->parse->jointree = (FromExpr *) jtnode;
else
root->parse->jointree = makeFromExpr(list_make1(jtnode), NULL);
}
/*
@@ -144,9 +153,9 @@ pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
{
FromExpr *f = (FromExpr *) jtnode;
List *newfromlist = NIL;
Node *newquals;
List *subfromlist = NIL;
Relids frelids = NULL;
FromExpr *newf;
Node *jtlink;
ListCell *l;
/* First, recurse to process children and collect their relids */
@@ -161,26 +170,32 @@ pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
newfromlist = lappend(newfromlist, newchild);
frelids = bms_join(frelids, childrelids);
}
/* Build the replacement FromExpr; no quals yet */
newf = makeFromExpr(newfromlist, NULL);
/* Set up a link representing the rebuilt jointree */
jtlink = (Node *) newf;
/* Now process qual --- all children are available for use */
newquals = pull_up_sublinks_qual_recurse(root, f->quals, frelids,
&subfromlist);
/* Any pulled-up subqueries can just be attached to the fromlist */
newfromlist = list_concat(newfromlist, subfromlist);
newf->quals = pull_up_sublinks_qual_recurse(root, f->quals, frelids,
&jtlink);
/*
* Note that the result will be either newf, or a stack of JoinExprs
* with newf at the base. We rely on subsequent optimization steps
* to flatten this and rearrange the joins as needed.
*
* Although we could include the pulled-up subqueries in the returned
* relids, there's no need since upper quals couldn't refer to their
* outputs anyway.
*/
*relids = frelids;
jtnode = (Node *) makeFromExpr(newfromlist, newquals);
jtnode = jtlink;
}
else if (IsA(jtnode, JoinExpr))
{
JoinExpr *j;
Relids leftrelids;
Relids rightrelids;
List *subfromlist = NIL;
Node *jtlink;
/*
* Make a modifiable copy of join node, but don't bother copying
@@ -188,6 +203,7 @@ pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
*/
j = (JoinExpr *) palloc(sizeof(JoinExpr));
memcpy(j, jtnode, sizeof(JoinExpr));
jtlink = (Node *) j;
/* Recurse to process children and collect their relids */
j->larg = pull_up_sublinks_jointree_recurse(root, j->larg,
@@ -197,13 +213,15 @@ pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
/*
* Now process qual, showing appropriate child relids as available,
* and then attach any pulled-up jointree items at the right place.
* The pulled-up items must go below where the quals that refer to
* them will be placed. Since the JoinExpr itself can only handle
* two child nodes, we hack up a valid jointree by inserting dummy
* FromExprs that have no quals. These should get flattened out
* during deconstruct_recurse(), so they won't impose any extra
* overhead.
* and attach any pulled-up jointree items at the right place.
* In the inner-join case we put new JoinExprs above the existing one
* (much as for a FromExpr-style join). In outer-join cases the
* new JoinExprs must go into the nullable side of the outer join.
* The point of the available_rels machinations is to ensure that we
* only pull up quals for which that's okay.
*
* We don't expect to see any pre-existing JOIN_SEMI or JOIN_ANTI
* nodes here.
*/
switch (j->jointype)
{
@@ -211,22 +229,12 @@ pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
bms_union(leftrelids,
rightrelids),
&subfromlist);
/* We arbitrarily put pulled-up subqueries into right child */
if (subfromlist)
j->rarg = (Node *) makeFromExpr(lcons(j->rarg,
subfromlist),
NULL);
&jtlink);
break;
case JOIN_LEFT:
j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
rightrelids,
&subfromlist);
/* Any pulled-up subqueries must go into right child */
if (subfromlist)
j->rarg = (Node *) makeFromExpr(lcons(j->rarg,
subfromlist),
NULL);
&j->rarg);
break;
case JOIN_FULL:
/* can't do anything with full-join quals */
@@ -234,12 +242,7 @@ pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
case JOIN_RIGHT:
j->quals = pull_up_sublinks_qual_recurse(root, j->quals,
leftrelids,
&subfromlist);
/* Any pulled-up subqueries must go into left child */
if (subfromlist)
j->larg = (Node *) makeFromExpr(lcons(j->larg,
subfromlist),
NULL);
&j->larg);
break;
default:
elog(ERROR, "unrecognized join type: %d",
@@ -255,9 +258,10 @@ pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
* levels would mistakenly think they couldn't use references to this
* join.
*/
*relids = bms_add_member(bms_join(leftrelids, rightrelids),
j->rtindex);
jtnode = (Node *) j;
*relids = bms_join(leftrelids, rightrelids);
if (j->rtindex)
*relids = bms_add_member(*relids, j->rtindex);
jtnode = jtlink;
}
else
elog(ERROR, "unrecognized node type: %d",
@@ -268,40 +272,47 @@ pull_up_sublinks_jointree_recurse(PlannerInfo *root, Node *jtnode,
/*
* Recurse through top-level qual nodes for pull_up_sublinks()
*
* Caller must have initialized *fromlist to NIL. We append any new
* jointree items to that list.
* jtlink points to the link in the jointree where any new JoinExprs should be
* inserted. If we find multiple pull-up-able SubLinks, they'll get stacked
* there in the order we encounter them. We rely on subsequent optimization
* to rearrange the stack if appropriate.
*/
static Node *
pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
Relids available_rels, List **fromlist)
Relids available_rels, Node **jtlink)
{
if (node == NULL)
return NULL;
if (IsA(node, SubLink))
{
SubLink *sublink = (SubLink *) node;
Node *new_qual;
List *new_fromlist;
JoinExpr *j;
/* Is it a convertible ANY or EXISTS clause? */
if (sublink->subLinkType == ANY_SUBLINK)
{
if (convert_ANY_sublink_to_join(root, sublink,
available_rels,
&new_qual, &new_fromlist))
j = convert_ANY_sublink_to_join(root, sublink,
available_rels);
if (j)
{
*fromlist = list_concat(*fromlist, new_fromlist);
return new_qual;
/* Yes, insert the new join node into the join tree */
j->larg = *jtlink;
*jtlink = (Node *) j;
/* and return NULL representing constant TRUE */
return NULL;
}
}
else if (sublink->subLinkType == EXISTS_SUBLINK)
{
if (convert_EXISTS_sublink_to_join(root, sublink, false,
available_rels,
&new_qual, &new_fromlist))
j = convert_EXISTS_sublink_to_join(root, sublink, false,
available_rels);
if (j)
{
*fromlist = list_concat(*fromlist, new_fromlist);
return new_qual;
/* Yes, insert the new join node into the join tree */
j->larg = *jtlink;
*jtlink = (Node *) j;
/* and return NULL representing constant TRUE */
return NULL;
}
}
/* Else return it unmodified */
@@ -311,19 +322,21 @@ pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
{
/* If the immediate argument of NOT is EXISTS, try to convert */
SubLink *sublink = (SubLink *) get_notclausearg((Expr *) node);
Node *new_qual;
List *new_fromlist;
JoinExpr *j;
if (sublink && IsA(sublink, SubLink))
{
if (sublink->subLinkType == EXISTS_SUBLINK)
{
if (convert_EXISTS_sublink_to_join(root, sublink, true,
available_rels,
&new_qual, &new_fromlist))
j = convert_EXISTS_sublink_to_join(root, sublink, true,
available_rels);
if (j)
{
*fromlist = list_concat(*fromlist, new_fromlist);
return new_qual;
/* Yes, insert the new join node into the join tree */
j->larg = *jtlink;
*jtlink = (Node *) j;
/* and return NULL representing constant TRUE */
return NULL;
}
}
}
@@ -339,14 +352,22 @@ pull_up_sublinks_qual_recurse(PlannerInfo *root, Node *node,
foreach(l, ((BoolExpr *) node)->args)
{
Node *oldclause = (Node *) lfirst(l);
Node *newclause;
newclauses = lappend(newclauses,
pull_up_sublinks_qual_recurse(root,
oldclause,
available_rels,
fromlist));
newclause = pull_up_sublinks_qual_recurse(root,
oldclause,
available_rels,
jtlink);
if (newclause)
newclauses = lappend(newclauses, newclause);
}
return (Node *) make_andclause(newclauses);
/* We might have got back fewer clauses than we started with */
if (newclauses == NIL)
return NULL;
else if (list_length(newclauses) == 1)
return (Node *) linitial(newclauses);
else
return (Node *) make_andclause(newclauses);
}
/* Stop if not an AND */
return node;
@@ -489,6 +510,8 @@ pull_up_subqueries(PlannerInfo *root, Node *jtnode,
below_outer_join, false);
break;
case JOIN_LEFT:
case JOIN_SEMI:
case JOIN_ANTI:
j->larg = pull_up_subqueries(root, j->larg,
below_outer_join, false);
j->rarg = pull_up_subqueries(root, j->rarg,
@@ -702,12 +725,12 @@ pull_up_simple_subquery(PlannerInfo *root, Node *jtnode, RangeTblEntry *rte,
parse->rowMarks = list_concat(parse->rowMarks, subquery->rowMarks);
/*
* We also have to fix the relid sets of any FlattenedSubLink and
* PlaceHolderVar nodes in the parent query. (This could perhaps be done
* by ResolveNew, but it would clutter that routine's API unreasonably.)
* Note in particular that any PlaceHolderVar nodes just created by
* insert_targetlist_placeholders() will be adjusted, so having created
* them with the subquery's varno is correct.
* We also have to fix the relid sets of any PlaceHolderVar nodes in the
* parent query. (This could perhaps be done by ResolveNew, but it would
* clutter that routine's API unreasonably.) Note in particular that any
* PlaceHolderVar nodes just created by insert_targetlist_placeholders()
* will be adjusted, so having created them with the subquery's varno is
* correct.
*
* Likewise, relids appearing in AppendRelInfo nodes have to be fixed.
* We already checked that this won't require introducing multiple
@@ -1419,6 +1442,14 @@ reduce_outer_joins_pass2(Node *jtnode,
jointype = JOIN_RIGHT;
}
break;
case JOIN_SEMI:
case JOIN_ANTI:
/*
* These could only have been introduced by pull_up_sublinks,
* so there's no way that upper quals could refer to their
* righthand sides, and no point in checking.
*/
break;
default:
elog(ERROR, "unrecognized join type: %d",
(int) jointype);
@@ -1475,14 +1506,15 @@ reduce_outer_joins_pass2(Node *jtnode,
}
/* Apply the jointype change, if any, to both jointree node and RTE */
if (jointype != j->jointype)
if (rtindex && jointype != j->jointype)
{
RangeTblEntry *rte = rt_fetch(rtindex, root->parse->rtable);
Assert(rte->rtekind == RTE_JOIN);
Assert(rte->jointype == j->jointype);
rte->jointype = j->jointype = jointype;
rte->jointype = jointype;
}
j->jointype = jointype;
/* Only recurse if there's more to do below here */
if (left_state->contains_outer || right_state->contains_outer)
@@ -1542,7 +1574,7 @@ reduce_outer_joins_pass2(Node *jtnode,
pass_nonnullable_vars = local_nonnullable_vars;
pass_forced_null_vars = local_forced_null_vars;
}
else if (jointype != JOIN_FULL) /* ie, LEFT or ANTI */
else if (jointype != JOIN_FULL) /* ie, LEFT/SEMI/ANTI */
{
/* can't pass local constraints to non-nullable side */
pass_nonnullable_rels = nonnullable_rels;
@@ -1564,7 +1596,7 @@ reduce_outer_joins_pass2(Node *jtnode,
if (right_state->contains_outer)
{
if (jointype != JOIN_FULL) /* ie, INNER, LEFT or ANTI */
if (jointype != JOIN_FULL) /* ie, INNER/LEFT/SEMI/ANTI */
{
/* pass appropriate constraints, per comment above */
pass_nonnullable_rels = local_nonnullable_rels;
@@ -1595,10 +1627,10 @@ reduce_outer_joins_pass2(Node *jtnode,
* substitute_multiple_relids - adjust node relid sets after pulling up
* a subquery
*
* Find any FlattenedSubLink or PlaceHolderVar nodes in the given tree that
* reference the pulled-up relid, and change them to reference the replacement
* relid(s). We do not need to recurse into subqueries, since no subquery of
* the current top query could (yet) contain such a reference.
* Find any PlaceHolderVar nodes in the given tree that reference the
* pulled-up relid, and change them to reference the replacement relid(s).
* We do not need to recurse into subqueries, since no subquery of the current
* top query could (yet) contain such a reference.
*
* NOTE: although this has the form of a walker, we cheat and modify the
* nodes in-place. This should be OK since the tree was copied by ResolveNew
@@ -1618,26 +1650,6 @@ substitute_multiple_relids_walker(Node *node,
{
if (node == NULL)
return false;
if (IsA(node, FlattenedSubLink))
{
FlattenedSubLink *fslink = (FlattenedSubLink *) node;
if (bms_is_member(context->varno, fslink->lefthand))
{
fslink->lefthand = bms_union(fslink->lefthand,
context->subrelids);
fslink->lefthand = bms_del_member(fslink->lefthand,
context->varno);
}
if (bms_is_member(context->varno, fslink->righthand))
{
fslink->righthand = bms_union(fslink->righthand,
context->subrelids);
fslink->righthand = bms_del_member(fslink->righthand,
context->varno);
}
/* fall through to examine children */
}
if (IsA(node, PlaceHolderVar))
{
PlaceHolderVar *phv = (PlaceHolderVar *) node;
@@ -1757,7 +1769,7 @@ get_relids_in_jointree(Node *jtnode, bool include_joins)
result = get_relids_in_jointree(j->larg, include_joins);
result = bms_join(result,
get_relids_in_jointree(j->rarg, include_joins));
if (include_joins)
if (include_joins && j->rtindex)
result = bms_add_member(result, j->rtindex);
}
else

19
src/backend/optimizer/prep/prepunion.c
View File

@@ -22,7 +22,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.165 2009/02/06 23:43:23 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.166 2009/02/25 03:30:37 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -1587,23 +1587,6 @@ adjust_appendrel_attrs_mutator(Node *node, AppendRelInfo *context)
j->rtindex = context->child_relid;
return (Node *) j;
}
if (IsA(node, FlattenedSubLink))
{
/* Copy the FlattenedSubLink node with correct mutation of subnodes */
FlattenedSubLink *fslink;
fslink = (FlattenedSubLink *) expression_tree_mutator(node,
adjust_appendrel_attrs_mutator,
(void *) context);
/* now fix FlattenedSubLink's relid sets */
fslink->lefthand = adjust_relid_set(fslink->lefthand,
context->parent_relid,
context->child_relid);
fslink->righthand = adjust_relid_set(fslink->righthand,
context->parent_relid,
context->child_relid);
return (Node *) fslink;
}
if (IsA(node, PlaceHolderVar))
{
/* Copy the PlaceHolderVar node with correct mutation of subnodes */

38
src/backend/optimizer/util/clauses.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.275 2009/01/09 15:46:10 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.276 2009/02/25 03:30:37 tgl Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@@ -1300,15 +1300,6 @@ find_nonnullable_rels_walker(Node *node, bool top_level)
expr->booltesttype == IS_NOT_UNKNOWN))
result = find_nonnullable_rels_walker((Node *) expr->arg, false);
}
else if (IsA(node, FlattenedSubLink))
{
/* JOIN_SEMI sublinks preserve strictness, but JOIN_ANTI ones don't */
FlattenedSubLink *expr = (FlattenedSubLink *) node;
if (expr->jointype == JOIN_SEMI)
result = find_nonnullable_rels_walker((Node *) expr->quals,
top_level);
}
else if (IsA(node, PlaceHolderVar))
{
PlaceHolderVar *phv = (PlaceHolderVar *) node;
@@ -1511,15 +1502,6 @@ find_nonnullable_vars_walker(Node *node, bool top_level)
expr->booltesttype == IS_NOT_UNKNOWN))
result = find_nonnullable_vars_walker((Node *) expr->arg, false);
}
else if (IsA(node, FlattenedSubLink))
{
/* JOIN_SEMI sublinks preserve strictness, but JOIN_ANTI ones don't */
FlattenedSubLink *expr = (FlattenedSubLink *) node;
if (expr->jointype == JOIN_SEMI)
result = find_nonnullable_vars_walker((Node *) expr->quals,
top_level);
}
else if (IsA(node, PlaceHolderVar))
{
PlaceHolderVar *phv = (PlaceHolderVar *) node;
@@ -2943,24 +2925,6 @@ eval_const_expressions_mutator(Node *node,
newbtest->booltesttype = btest->booltesttype;
return (Node *) newbtest;
}
if (IsA(node, FlattenedSubLink))
{
FlattenedSubLink *fslink = (FlattenedSubLink *) node;
FlattenedSubLink *newfslink;
Expr *quals;
/* Simplify and also canonicalize the arguments */
quals = (Expr *) eval_const_expressions_mutator((Node *) fslink->quals,
context);
quals = canonicalize_qual(quals);
newfslink = makeNode(FlattenedSubLink);
newfslink->jointype = fslink->jointype;
newfslink->lefthand = fslink->lefthand;
newfslink->righthand = fslink->righthand;
newfslink->quals = quals;
return (Node *) newfslink;
}
if (IsA(node, PlaceHolderVar) && context->estimate)
{
/*

20
src/backend/optimizer/util/var.c
View File

@@ -14,7 +14,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/var.c,v 1.83 2009/01/01 17:23:45 momjian Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/var.c,v 1.84 2009/02/25 03:30:37 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -766,24 +766,6 @@ flatten_join_alias_vars_mutator(Node *node,
/* Recurse in case join input is itself a join */
return flatten_join_alias_vars_mutator(newvar, context);
}
if (IsA(node, FlattenedSubLink))
{
/* Copy the FlattenedSubLink node with correct mutation of subnodes */
FlattenedSubLink *fslink;
fslink = (FlattenedSubLink *) expression_tree_mutator(node,
flatten_join_alias_vars_mutator,
(void *) context);
/* now fix FlattenedSubLink's relid sets */
if (context->sublevels_up == 0)
{
fslink->lefthand = alias_relid_set(context->root,
fslink->lefthand);
fslink->righthand = alias_relid_set(context->root,
fslink->righthand);
}
return (Node *) fslink;
}
if (IsA(node, PlaceHolderVar))
{
/* Copy the PlaceHolderVar node with correct mutation of subnodes */