*
* prepjointree.cpp
* Planner preprocessing for subqueries and join tree manipulation.
*
* NOTE: the intended sequence for invoking these operations is
* replace_empty_jointree
* pull_up_sublinks
* inline_set_returning_functions
* pull_up_subqueries
* flatten_simple_union_all
* do expression preprocessing (including flattening JOIN alias vars)
* reduce_outer_joins
* remove_useless_result_rtes
*
*
* Portions Copyright (c) 2020 Huawei Technologies Co.,Ltd.
* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
* Portions Copyright (c) 2021, openGauss Contributors
*
*
* IDENTIFICATION
* src/gausskernel/optimizer/prep/prepjointree.cpp
*
* -------------------------------------------------------------------------
*/
#include "postgres.h"
#include "knl/knl_variable.h"
#include "catalog/pg_type.h"
#include "nodes/makefuncs.h"
#include "nodes/nodeFuncs.h"
#include "parser/parse_hint.h"
#include "optimizer/clauses.h"
#include "optimizer/nodegroups.h"
#include "optimizer/placeholder.h"
#include "optimizer/prep.h"
#include "optimizer/subselect.h"
#include "optimizer/tlist.h"
#include "parser/parse_relation.h"
#include "parser/parsetree.h"
#include "rewrite/rewriteManip.h"
#ifdef PGXC
#include "access/sysattr.h"
#include "pgxc/pgxc.h"
#endif
#include "optimizer/streamplan.h"
#include "parser/parse_oper.h"
#include "utils/lsyscache.h"
#include "access/transam.h"
#include "catalog/pg_operator.h"
#include "nodes/pg_list.h"
#include "optimizer/planner.h"
typedef struct pullup_replace_vars_context {
PlannerInfo* root;
List* targetlist;
RangeTblEntry* target_rte;
Relids relids;
* pullup (set only if target_rte->lateral) */
bool* outer_hasSubLinks;
int varno;
bool need_phvs;
bool wrap_non_vars;
Node** rv_cache;
} pullup_replace_vars_context;
typedef struct reduce_outer_joins_state {
Relids relids;
bool contains_outer;
List* sub_states;
} reduce_outer_joins_state;
static Node* pull_up_sublinks_jointree_recurse(PlannerInfo* root, Node* jtnode, Relids* relids, Node* all_quals = NULL);
static Node* pull_up_sublinks_qual_recurse(PlannerInfo* root, Node* node, Node** jtlink1, Relids *available_rels1,
Node** jtlink2, Relids *available_rels2, Node* all_quals = NULL);
static Node *pull_up_subqueries_recurse(PlannerInfo *root, Node *jtnode,
JoinExpr *lowest_outer_join,
JoinExpr *lowest_nulling_outer_join,
AppendRelInfo *containing_appendrel);
static Node* pull_up_simple_subquery(PlannerInfo* root, Node* jtnode,
RangeTblEntry* rte, JoinExpr* lowest_outer_join, JoinExpr *lowest_nulling_outer_join,
AppendRelInfo* containing_appendrel);
static Node* pull_up_simple_union_all(PlannerInfo* root, Node* jtnode, RangeTblEntry* rte);
static void pull_up_union_leaf_queries(
Node* setOp, PlannerInfo* root, int parentRTindex, Query* setOpQuery, int childRToffset);
static void make_setop_translation_list(Query* query, Index newvarno, List** translated_vars);
static bool is_simple_lateral_subquery(Query* subquery, JoinExpr *lowest_outer_join);
static bool is_simple_subquery(Query* subquery, RangeTblEntry *rte, JoinExpr *lowest_outer_join);
static bool is_simple_union_all(Query* subquery);
static bool is_simple_union_all_recurse(Node* setOp, Query* setOpQuery, List* colTypes);
static bool is_safe_append_member(Query* subquery);
static bool jointree_contains_lateral_outer_refs(Node *jtnode,
bool restricted, Relids safe_upper_varnos);
static void replace_vars_in_jointree(Node* jtnode, pullup_replace_vars_context* context, JoinExpr* lowest_nulling_outer_join);
static Node* pullup_replace_vars(Node* expr, pullup_replace_vars_context* context);
static Node* pullup_replace_vars_callback(Var* var, replace_rte_variables_context* context);
static Query *pullup_replace_vars_subquery(Query *query, pullup_replace_vars_context *context);
static reduce_outer_joins_state* reduce_outer_joins_pass1(Node* jtnode);
static void reduce_outer_joins_pass2(Node* jtnode, reduce_outer_joins_state* state, PlannerInfo* root,
Relids nonnullable_rels, List* nonnullable_vars, List* forced_null_vars);
static void substitute_multiple_relids(Node* node, int varno, Relids subrelids);
static void fix_append_rel_relids(List* append_rel_list, int varno, Relids subrelids);
static Node* find_jointree_node_for_rel(Node* jtnode, int relid);
static Node* deleteRelatedNullTest(Node* node, PlannerInfo* root);
static Node* reduce_inequality_fulljoins_jointree_recurse(PlannerInfo* root, Node* jtnode);
static Node *pull_up_sublinks_targetlist(PlannerInfo *root, Node *node,
Node *jtnode, Relids *relids,
Node **newTargetList,
Node *whereQuals);
static void pull_up_sublinks_having(PlannerInfo* root);
static bool is_safe_pull_up_sublink_having(PlannerInfo* root);
#ifndef ENABLE_MULTIPLE_NODES
static bool find_rownum_in_quals(PlannerInfo *root);
static bool contains_swctes(const PlannerInfo *root);
#endif
* replace_empty_jointree
* If the Query's jointree is empty, replace it with a dummy RTE_RESULT
* relation.
*
* By doing this, we can avoid a bunch of corner cases that formerly existed
* for SELECTs with omitted FROM clauses. An example is that a subquery
* with empty jointree previously could not be pulled up, because that would
* have resulted in an empty relid set, making the subquery not uniquely
* identifiable for join or PlaceHolderVar processing.
*
* Unlike most other functions in this file, this function doesn't recurse;
* we rely on other processing to invoke it on sub-queries at suitable times.
*/
void replace_empty_jointree(Query *parse)
{
RangeTblEntry *rte;
Index rti;
RangeTblRef *rtr;
if (parse->jointree->fromlist != NIL)
return;
if (parse->setOperations)
return;
rte = makeNode(RangeTblEntry);
rte->rtekind = RTE_RESULT;
rte->eref = makeAlias("*RESULT*", NIL);
parse->rtable = lappend(parse->rtable, rte);
rti = list_length(parse->rtable);
rtr = makeNode(RangeTblRef);
rtr->rtindex = rti;
parse->jointree->fromlist = list_make1(rtr);
}
#ifndef ENABLE_MULTIPLE_NODES
* helper function to check if SWCB ctes contaisn in current SubQuery, normally help us to
* idenfity if it is OK to appy SWCB related optimization steps
*/
static bool contains_swctes(const PlannerInfo *root)
{
if (root->parse == NULL || root->parse->cteList == NIL) {
return false;
}
List *cteList = root->parse->cteList;
ListCell *lc = NULL;
bool found = false;
foreach(lc, cteList) {
CommonTableExpr *cte = (CommonTableExpr *)lfirst(lc);
if (cte->swoptions != NULL) {
found = true;
break;
}
}
return found;
}
#endif
* pull_up_sublinks
* Attempt to pull up ANY and EXISTS SubLinks to be treated as
* semijoins or anti-semijoins.
*
* A clause "foo op ANY (sub-SELECT)" can be processed by pulling the
* sub-SELECT up to become a rangetable entry and treating the implied
* comparisons as quals of a semijoin. However, this optimization *only*
* works at the top level of WHERE or a JOIN/ON clause, because we cannot
* 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 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.
*
* Under similar conditions, EXISTS and NOT EXISTS clauses can be handled
* by pulling up the sub-SELECT and creating a semijoin or anti-semijoin.
*
* This routine searches for such clauses and does the necessary parsetree
* transformations if any are found.
*
* This routine has to run before preprocess_expression(), so the quals
* clauses are not yet reduced to implicit-AND format. That means we need
* to recursively search through explicit AND clauses, which are
* probably only binary ANDs. We stop as soon as we hit a non-AND item.
*/
void pull_up_sublinks(PlannerInfo* root)
{
Node* jtnode = NULL;
Relids relids;
#ifndef ENABLE_MULTIPLE_NODES
if (find_rownum_in_quals(root)) {
return;
}
if (contains_swctes(root)) {
return;
}
#endif
if (ENABLE_SUBLINK_PULLUP_ENHANCED() &&
permit_from_rewrite_hint(root, SUBLINK_PULLUP_ENHANCED) &&
is_safe_pull_up_sublink_having(root)) {
pull_up_sublinks_having(root);
}
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.
*/
FromExpr* old_jointree = root->parse->jointree;
if (IsA(jtnode, FromExpr))
root->parse->jointree = (FromExpr*)jtnode;
else
root->parse->jointree = makeFromExpr(list_make1(jtnode), NULL);
if ((u_sess->attr.attr_sql.rewrite_rule & SUBLINK_PULLUP_IN_TARGETLIST) && permit_from_rewrite_hint(root, SUBLINK_PULLUP_IN_TARGETLIST)) {
Node *newTargetList = NULL;
Node *whereQuals = root->parse->jointree->quals;
jtnode = pull_up_sublinks_targetlist(root,
(Node *)root->parse->targetList,
(Node *)root->parse->jointree,
&relids,
&newTargetList,
whereQuals);
* 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 (newTargetList != NULL)
root->parse->targetList = (List *)replace_node_clause((Node *)root->parse->targetList,
(Node *)root->parse->targetList, newTargetList, RNC_REPLACE_FIRST_ONLY);
if (IsA(jtnode, FromExpr))
root->parse->jointree = (FromExpr *) jtnode;
else
root->parse->jointree = makeFromExpr(list_make1(jtnode), NULL);
}
if (!equal(root->parse->jointree, old_jointree)) {
root->parse->is_from_sublink_rewrite = true;
}
}
* @Description: Put this qual to correct place.
* @in new_node - New node sublink pull up after.
* @in old_node - Old node sublink pull up before.
* @in qual - Need set qual clause.
* @in old_node_relids - old node available relids.
* @return - new node.
*/
Node* assign_qual_clause(Node* new_node, Node* old_node, Node* qual, Relids old_node_relids)
{
if (qual == NULL) {
return new_node;
}
Relids qual_varnos = pull_varnos(qual);
* We need add this quals to new_node if old_node_relids can not include qual_varnos.
* than can happend when or_clause pull up.
*/
if (!bms_is_subset(qual_varnos, old_node_relids)) {
if (IsA(new_node, FromExpr)) {
((FromExpr*)new_node)->quals = qual;
} else {
new_node = (Node*)makeFromExpr(list_make1(new_node), qual);
}
}
else {
if (IsA(old_node, FromExpr)) {
((FromExpr*)old_node)->quals = qual;
} else {
((JoinExpr*)old_node)->quals = qual;
}
}
bms_free_ext(qual_varnos);
return new_node;
}
* Recurse through jointree nodes for pull_up_sublinks()
*
* In addition to returning the possibly-modified jointree node, we return
* a relids set of the contained rels into *relids.
*/
static Node* pull_up_sublinks_jointree_recurse(PlannerInfo* root, Node* jtnode, Relids* relids, Node* all_quals)
{
if (jtnode == NULL) {
*relids = NULL;
} else if (IsA(jtnode, RangeTblRef)) {
int varno = ((RangeTblRef*)jtnode)->rtindex;
*relids = bms_make_singleton(varno);
} else if (IsA(jtnode, FromExpr)) {
FromExpr* f = (FromExpr*)jtnode;
List* newfromlist = NIL;
Relids frelids = NULL;
FromExpr* newf = NULL;
Node* jtlink = NULL;
ListCell* l = NULL;
Node* qual = NULL;
Relids current_relids = NULL;
foreach (l, f->fromlist) {
Node* newchild = NULL;
Relids childrelids;
newchild = pull_up_sublinks_jointree_recurse(root, (Node*)lfirst(l), &childrelids, f->quals);
newfromlist = lappend(newfromlist, newchild);
current_relids = bms_union(current_relids, childrelids);
frelids = bms_join(frelids, childrelids);
}
newf = makeFromExpr(newfromlist, NULL);
jtlink = (Node*)newf;
qual = pull_up_sublinks_qual_recurse(root, f->quals, &jtlink, &frelids, NULL, NULL, f->quals);
* Put this qual to correct place. It is mean this qual only need put to
* original FromExpr, also can put to new generate jtlink, e.g. or_clause pull up.
*
* For examlpe:
* select * from t1 where exists (select a from t2 where t1.a = t2.a) or
* exists (select b from t3 where t1.b = t3.b);
*
* This query be equivalent to:
*
* select t1.* from t1 left join (select t2.a from t2 group by t2.a) as tt1 on (t1.a = tt1.a)
* left join (select t3.b from t3 group by t3.a) as tt2 on (tt2.b = t1.b)
* where tt1.a is not null or tt2.b is not null;
*
* This case mean qual 'tt1.a is not null or tt2.b is not null' need put to behind all join
* instead of behind table t1.
*/
jtlink = assign_qual_clause(jtlink, (Node*)newf, qual, current_relids);
* 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 = jtlink;
} else if (IsA(jtnode, JoinExpr)) {
JoinExpr* j = NULL;
Relids leftrelids;
Relids rightrelids;
Node* jtlink = NULL;
Node* quals = NULL;
* Make a modifiable copy of join node, but don't bother copying its
* subnodes (yet).
*/
j = (JoinExpr*)palloc(sizeof(JoinExpr));
errno_t errorno = memcpy_s(j, sizeof(JoinExpr), jtnode, sizeof(JoinExpr));
securec_check(errorno, "", "");
jtlink = (Node*)j;
j->larg = pull_up_sublinks_jointree_recurse(root, j->larg, &leftrelids);
j->rarg = pull_up_sublinks_jointree_recurse(root, j->rarg, &rightrelids);
Relids union_relids = bms_union(leftrelids, rightrelids);
* Now process qual, showing appropriate child relids as available,
* 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) {
case JOIN_INNER:
quals = pull_up_sublinks_qual_recurse(
root, j->quals, &jtlink, &union_relids, NULL, NULL, all_quals);
* To inner join, we need special manage this quals, else can lead to error
* when or_clause be pulled up.
* For example:
* select 1 from t1 inner join t2 on (exists (select * from t3 where t1.a = t3.a)
* or exists (select * from t4 where t2.a = t4.a));
*
* This query be equivalent to:
*
* select 1 from t1 inner join t2 on (1 = 1)
* left join (select t3.a from t3 group by t3.a) as tt3 on (t1.a = t3.a)
* left join (select t4.a from t4 group by t4.a) as tt4 on t2.a = t4.a)
* where tt3.a is not null or tt4.a is not null;
*
* To this query, return quals is 'tt3.a is not null or tt4.a is not null',
* this qual need put to behind all join, can not put to behind t1 join t2 that will lead
* to error(JOIN qualification cannot refer to other relations) because can not find tt3.a and tt4.a.
*/
j->quals = NULL;
jtlink = assign_qual_clause(jtlink, (Node*)j, quals, bms_union(leftrelids, rightrelids));
break;
case JOIN_LEFT:
case JOIN_LEFT_ANTI_FULL:
j->quals = pull_up_sublinks_qual_recurse(root, j->quals, &j->rarg, &rightrelids, NULL, NULL);
break;
case JOIN_FULL:
case JOIN_SEMI:
case JOIN_ANTI:
if (u_sess->attr.attr_common.log_min_messages <= DEBUG2) {
ereport(DEBUG2, (errmodule(MOD_OPT_REWRITE),
errmsg("We record join type when semi_join=4 anti_join=5: %d", j->jointype)));
}
break;
case JOIN_RIGHT:
case JOIN_RIGHT_ANTI_FULL:
j->quals = pull_up_sublinks_qual_recurse(root, j->quals, &j->larg, &leftrelids, NULL, NULL);
break;
default: {
ereport(ERROR,
(errmodule(MOD_OPT),
errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE),
errmsg("unrecognized join type: %d", (int)j->jointype)));
} break;
}
* 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. But we *do* need to include the join's own rtindex
* because we haven't yet collapsed join alias variables, so upper
* levels would mistakenly think they couldn't use references to this
* join.
*/
*relids = bms_join(leftrelids, rightrelids);
if (j->rtindex)
*relids = bms_add_member(*relids, j->rtindex);
jtnode = jtlink;
} else {
ereport(ERROR,
(errmodule(MOD_OPT),
errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE),
errmsg("unrecognized node type: %d", (int)nodeTag(jtnode))));
}
return jtnode;
}
* Recurse through top-level qual nodes for pull_up_sublinks()
*
* jtlink1 points to the link in the jointree where any new JoinExprs should
* be inserted if they reference available_rels1 (i.e., available_rels1
* denotes the relations present underneath jtlink1). Optionally, jtlink2 can
* point to a second link where new JoinExprs should be inserted if they
* reference available_rels2 (pass NULL for both those arguments if not used).
* Note that SubLinks referencing both sets of variables cannot be optimized.
* If we find multiple pull-up-able SubLinks, they'll get stacked onto jtlink1
* and/or jtlink2 in the order we encounter them. We rely on subsequent
* optimization to rearrange the stack if appropriate.
*
* Returns the replacement qual node, or NULL if the qual should be removed.
*/
static Node* pull_up_sublinks_qual_recurse(PlannerInfo* root, Node* node, Node** jtlink1, Relids *available_rels1,
Node** jtlink2, Relids *available_rels2, Node* all_quals)
{
if (node == NULL)
return NULL;
if (IsA(node, SubLink)) {
SubLink* sublink = (SubLink*)node;
JoinExpr* j = NULL;
Relids child_rels;
if (has_no_expand_hint((Query*)sublink->subselect)) {
return node;
}
if (sublink->subLinkType == ANY_SUBLINK) {
if ((j = convert_ANY_sublink_to_join(root, sublink, false, *available_rels1)) != NULL) {
j->larg = *jtlink1;
*jtlink1 = (Node*)j;
j->rarg = pull_up_sublinks_jointree_recurse(root, j->rarg, &child_rels);
* Now recursively process the pulled-up quals. Any inserted
* joins can get stacked onto either j->larg or j->rarg,
* depending on which rels they reference.
*/
j->quals =
pull_up_sublinks_qual_recurse(root, j->quals, &j->larg, available_rels1, &j->rarg, &child_rels);
return NULL;
}
if (available_rels2 != NULL &&
(j = convert_ANY_sublink_to_join(root, sublink, false, *available_rels2)) != NULL) {
j->larg = *jtlink2;
*jtlink2 = (Node*)j;
j->rarg = pull_up_sublinks_jointree_recurse(root, j->rarg, &child_rels);
* Now recursively process the pulled-up quals. Any inserted
* joins can get stacked onto either j->larg or j->rarg,
* depending on which rels they reference.
*/
j->quals =
pull_up_sublinks_qual_recurse(root, j->quals, &j->larg, available_rels2, &j->rarg, &child_rels);
return NULL;
}
} else if (sublink->subLinkType == EXISTS_SUBLINK) {
if ((j = convert_EXISTS_sublink_to_join(root, sublink, false, *available_rels1)) != NULL) {
j->larg = *jtlink1;
*jtlink1 = (Node*)j;
j->rarg = pull_up_sublinks_jointree_recurse(root, j->rarg, &child_rels);
* Now recursively process the pulled-up quals. Any inserted
* joins can get stacked onto either j->larg or j->rarg,
* depending on which rels they reference.
*/
j->quals =
pull_up_sublinks_qual_recurse(root, j->quals, &j->larg, available_rels1, &j->rarg, &child_rels);
return NULL;
}
if (available_rels2 != NULL &&
(j = convert_EXISTS_sublink_to_join(root, sublink, false, *available_rels2)) != NULL) {
j->larg = *jtlink2;
*jtlink2 = (Node*)j;
j->rarg = pull_up_sublinks_jointree_recurse(root, j->rarg, &child_rels);
* Now recursively process the pulled-up quals. Any inserted
* joins can get stacked onto either j->larg or j->rarg,
* depending on which rels they reference.
*/
j->quals =
pull_up_sublinks_qual_recurse(root, j->quals, &j->larg, available_rels2, &j->rarg, &child_rels);
return NULL;
}
}
return node;
}
if (not_clause(node)) {
SubLink* sublink = (SubLink*)get_notclausearg((Expr*)node);
JoinExpr* j = NULL;
Relids child_rels;
if (sublink && IsA(sublink, SubLink)) {
if (sublink->subLinkType == EXISTS_SUBLINK) {
if ((j = convert_EXISTS_sublink_to_join(root, sublink, true, *available_rels1)) != NULL) {
j->larg = *jtlink1;
*jtlink1 = (Node*)j;
j->rarg = pull_up_sublinks_jointree_recurse(root, j->rarg, &child_rels);
* Now recursively process the pulled-up quals. Because
* we are underneath a NOT, we can't pull up sublinks that
* reference the left-hand stuff, but it's still okay to
* pull up sublinks referencing j->rarg.
*/
j->quals = pull_up_sublinks_qual_recurse(root, j->quals, &j->rarg, &child_rels, NULL, NULL);
return NULL;
}
if (available_rels2 != NULL &&
(j = convert_EXISTS_sublink_to_join(root, sublink, true, *available_rels2)) != NULL) {
j->larg = *jtlink2;
*jtlink2 = (Node*)j;
j->rarg = pull_up_sublinks_jointree_recurse(root, j->rarg, &child_rels);
* Now recursively process the pulled-up quals. Because
* we are underneath a NOT, we can't pull up sublinks that
* reference the left-hand stuff, but it's still okay to
* pull up sublinks referencing j->rarg.
*/
j->quals = pull_up_sublinks_qual_recurse(root, j->quals, &j->rarg, &child_rels, NULL, NULL);
return NULL;
}
} else if (sublink->subLinkType == ANY_SUBLINK) {
if ((j = convert_ANY_sublink_to_join(root, sublink, true, *available_rels1)) != NULL) {
j->larg = *jtlink1;
*jtlink1 = (Node*)j;
j->rarg = pull_up_sublinks_jointree_recurse(root, j->rarg, &child_rels);
* Now recursively process the pulled-up quals. Because
* we are underneath a NOT, we can't pull up sublinks that
* reference the left-hand stuff, but it's still okay to
* pull up sublinks referencing j->rarg.
*/
j->quals = pull_up_sublinks_qual_recurse(root, j->quals, &j->rarg, &child_rels, NULL, NULL);
return NULL;
}
if (available_rels2 != NULL &&
(j = convert_ANY_sublink_to_join(root, sublink, true, *available_rels2)) != NULL) {
j->larg = *jtlink2;
*jtlink2 = (Node*)j;
j->rarg = pull_up_sublinks_jointree_recurse(root, j->rarg, &child_rels);
* Now recursively process the pulled-up quals. Because
* we are underneath a NOT, we can't pull up sublinks that
* reference the left-hand stuff, but it's still okay to
* pull up sublinks referencing j->rarg.
*/
j->quals = pull_up_sublinks_qual_recurse(root, j->quals, &j->rarg, &child_rels, NULL, NULL);
return NULL;
}
}
}
return node;
}
if (and_clause(node)) {
List* newclauses = NIL;
ListCell* l = NULL;
foreach (l, ((BoolExpr*)node)->args) {
Node* oldclause = (Node*)lfirst(l);
Node* newclause = NULL;
newclause = pull_up_sublinks_qual_recurse(
root, oldclause, jtlink1, available_rels1, jtlink2, available_rels2, all_quals);
if (newclause != NULL)
newclauses = lappend(newclauses, newclause);
}
if (newclauses == NIL)
return NULL;
else if (list_length(newclauses) == 1)
return (Node*)linitial(newclauses);
else
return (Node*)make_andclause(newclauses);
}
if (DISABLE_SUBLINK_PULLUP_EXPR() && permit_from_rewrite_hint(root, SUBLINK_PULLUP_DISABLE_EXPR)) {
return node;
}
if (or_clause(node)) {
convert_ORCLAUSE_to_join(root, (BoolExpr*)node, jtlink1, available_rels1);
if (available_rels2 != NULL) {
convert_ORCLAUSE_to_join(root, (BoolExpr *)node, jtlink2, available_rels2);
}
return node;
}
if(IsA(node, OpExpr) || IsA(node, NullTest))
{
List *sublinkList = pull_sublink(node, 0, false);
if(sublinkList != NULL) {
ListCell *lc = NULL;
foreach(lc, sublinkList) {
Node *sublink = (Node*)lfirst(lc);
if (unlikely(!(IsA(sublink, SubLink))))
ereport(ERROR,
(errmodule(MOD_OPT_REWRITE),
errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("Node should be SubLink in pull_up_sublinks_qual_recurse")));
node = convert_EXPR_sublink_to_join(root, jtlink1,
node,
(SubLink*)sublink,
available_rels1,
all_quals);
if (available_rels2 != NULL) {
node = convert_EXPR_sublink_to_join(root, jtlink2,
node,
(SubLink*)sublink,
available_rels2,
all_quals);
}
}
}
return node;
}
return node;
}
* pull_up_sublinks_targetlist
* sublink pull up logic for sublinks in targetlist
*
* Parameters:
* @in root: planner info of current query level
* @in node: list of targetlist expression
* @in jtnode: from table structure
* @in relids: bitmap of relids that is visible to sublink
* @in/out newTargetList: converted targetlist
* @out: whereQuals: the where quals
*
* Returns: new formed from table structure
*/
static Node* pull_up_sublinks_targetlist(PlannerInfo *root,
Node *node,
Node *jtnode,
Relids *relids,
Node **newTargetList,
Node *whereQuals)
{
List *sublinkName = pull_sublink(node, 0, true);
List *sublinkList = pull_sublink(node, 0, false);
ListCell *lc = NULL;
ListCell *lc1 = NULL;
forboth(lc, sublinkList, lc1, sublinkName)
{
SubLink *sublink = (SubLink*) lfirst(lc);
if (has_no_expand_hint((Query*)sublink->subselect)) {
continue;
}
char *resname = (char*) lfirst(lc1);
Assert(IsA(sublink, SubLink));
if (sublink->subLinkType == EXPR_SUBLINK) {
* Return value is changed opexpr. Since we only modify
* the members of opExpr, so the return value can be ignored
*/
node = convert_EXPR_sublink_to_join(root, &jtnode,
node,
(SubLink*)sublink,
relids,
whereQuals, resname);
}
}
* The changed targetlist is returned to replace the original targetList.
* In this way, the sublink is excluded.
*/
*newTargetList = node;
return jtnode;
}
* inline_set_returning_functions
* Attempt to "inline" set-returning functions in the FROM clause.
*
* If an RTE_FUNCTION rtable entry invokes a set-returning function that
* contains just a simple SELECT, we can convert the rtable entry to an
* RTE_SUBQUERY entry exposing the SELECT directly. This is especially
* useful if the subquery can then be "pulled up" for further optimization,
* but we do it even if not, to reduce executor overhead.
*
* This has to be done before we have started to do any optimization of
* subqueries, else any such steps wouldn't get applied to subqueries
* obtained via inlining. However, we do it after pull_up_sublinks
* so that we can inline any functions used in SubLink subselects.
*
* Like most of the planner, this feels free to scribble on its input data
* structure.
*/
void inline_set_returning_functions(PlannerInfo* root)
{
ListCell* rt = NULL;
foreach (rt, root->parse->rtable) {
RangeTblEntry* rte = (RangeTblEntry*)lfirst(rt);
if (rte->rtekind == RTE_FUNCTION) {
Query* funcquery = NULL;
funcquery = inline_set_returning_function(root, rte);
if (funcquery != NULL) {
rte->rtekind = RTE_SUBQUERY;
rte->subquery = funcquery;
rte->funcexpr = NULL;
rte->funccoltypes = NIL;
rte->funccoltypmods = NIL;
rte->funccolcollations = NIL;
}
}
}
}
* This recursively processes the jointree and returns a modified jointree.
*/
Node *
pull_up_subqueries(PlannerInfo *root, Node *jtnode)
{
return pull_up_subqueries_recurse(root, jtnode, NULL, NULL, NULL);
}
* pull_up_subqueries_recurse
* Recursive guts of pull_up_subqueries.
*
* This recursively processes the jointree and returns a modified jointree.
*
* If this jointree node is within either side of an outer join, then
* lowest_outer_join references the lowest such JoinExpr node; otherwise
* it is NULL. We use this to constrain the effects of LATERAL subqueries.
*
* If this jointree node is within the nullable side of an outer join, then
* lowest_nulling_outer_join references the lowest such JoinExpr node;
* otherwise it is NULL. This forces use of the PlaceHolderVar mechanism for
* references to non-nullable targetlist items, but only for references above
* that join.
*
* If we are looking at a member subquery of an append relation,
* containing_appendrel describes that relation; else it is NULL.
* This forces use of the PlaceHolderVar mechanism for all non-Var targetlist
* items, and puts some additional restrictions on what can be pulled up.
*
* 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 to maintain
* validity of the jointree structure while recursing, in the following sense:
* whenever we recurse, all qual expressions in the tree must be reachable
* from the top level, in case the recursive call needs to modify them.
*
* Notice also that we can't turn pullup_replace_vars loose on the whole
* jointree, because it'd return a mutated copy of the tree; we have to
* invoke it just on the quals, instead. This behavior is what makes it
* reasonable to pass lowest_outer_join and lowest_nulling_outer_join as
* pointers rather than some more-indirect way of identifying the lowest
* OJs. Likewise, we don't replace append_rel_list members but only their
* substructure, so the containing_appendrel reference is safe to use.
*/
Node* pull_up_subqueries_recurse(
PlannerInfo* root, Node* jtnode, JoinExpr* lowest_outer_join, JoinExpr *lowest_nulling_outer_join,
AppendRelInfo* containing_appendrel)
{
if (jtnode == NULL)
return NULL;
#ifndef ENABLE_MULTIPLE_NODES
if(find_rownum_in_quals(root)) {
root->hasRownumQual = true;
}
#endif
if (IsA(jtnode, RangeTblRef)) {
int varno = ((RangeTblRef*)jtnode)->rtindex;
RangeTblEntry* rte = rt_fetch(varno, root->parse->rtable);
rte->subquery_pull_up = false;
* Is this a subquery RTE, and if so, is the subquery simple enough to
* pull up?
*
* If we are looking at an append-relation member, we can't pull it up
* unless is_safe_append_member says so.
*/
if (rte->rtekind == RTE_SUBQUERY && is_simple_subquery(rte->subquery, rte, lowest_outer_join) &&
(containing_appendrel == NULL || is_safe_append_member(rte->subquery)))
return pull_up_simple_subquery(root, jtnode, rte, lowest_outer_join, lowest_nulling_outer_join, containing_appendrel);
* Alternatively, is it a simple UNION ALL subquery? If so, flatten
* into an "append relation".
*
* It's safe to do this regardless of whether this query is itself an
* appendrel member. (If you're thinking we should try to flatten the
* two levels of appendrel together, you're right; but we handle that
* in set_append_rel_pathlist, not here.)
*
* In multi-node group scenario, we should not pull up union all because
* the branchs may be in different node group, we could not determine the
* group for append path
*/
if (rte->rtekind == RTE_SUBQUERY && is_simple_union_all(rte->subquery) &&
#ifndef ENABLE_MULTIPLE_NODES
!root->hasRownumQual &&
#endif
(!ng_is_multiple_nodegroup_scenario()))
return pull_up_simple_union_all(root, jtnode, rte);
} else if (IsA(jtnode, FromExpr)) {
FromExpr* f = (FromExpr*)jtnode;
ListCell* l = NULL;
Assert(containing_appendrel == NULL);
foreach (l, f->fromlist)
lfirst(l) = pull_up_subqueries_recurse(root, (Node*)lfirst(l), lowest_outer_join, lowest_nulling_outer_join, NULL);
} else if (IsA(jtnode, JoinExpr)) {
JoinExpr* j = (JoinExpr*)jtnode;
Assert(containing_appendrel == NULL);
switch (j->jointype) {
case JOIN_INNER:
j->larg = pull_up_subqueries_recurse(root, j->larg, lowest_outer_join, lowest_nulling_outer_join, NULL);
j->rarg = pull_up_subqueries_recurse(root, j->rarg, lowest_outer_join, lowest_nulling_outer_join, NULL);
break;
case JOIN_LEFT:
case JOIN_SEMI:
case JOIN_ANTI:
case JOIN_LEFT_ANTI_FULL:
j->larg = pull_up_subqueries_recurse(root, j->larg, lowest_outer_join, lowest_nulling_outer_join, NULL);
j->rarg = pull_up_subqueries_recurse(root, j->rarg, j, j, NULL);
break;
case JOIN_FULL:
j->larg = pull_up_subqueries_recurse(root, j->larg, j, j, NULL);
j->rarg = pull_up_subqueries_recurse(root, j->rarg, j, j, NULL);
break;
case JOIN_RIGHT:
case JOIN_RIGHT_ANTI_FULL:
j->larg = pull_up_subqueries_recurse(root, j->larg, j, j, NULL);
j->rarg = pull_up_subqueries_recurse(root, j->rarg, lowest_outer_join, lowest_nulling_outer_join, NULL);
break;
default: {
ereport(ERROR,
(errmodule(MOD_OPT),
errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE),
errmsg("unrecognized join type: %d", (int)j->jointype)));
} break;
}
} else {
ereport(ERROR,
(errmodule(MOD_OPT),
errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE),
errmsg("unrecognized node type: %d", (int)nodeTag(jtnode))));
}
return jtnode;
}
* @Description: Pull up subquery's hint.
* @in root: query level info.
* @in parse: Parent query.
* @in hint_state: Subquery's hint.
*/
void pull_up_subquery_hint(PlannerInfo* root, Query* parse, HintState* hint_state)
{
if (parse->hintState == NULL) {
parse->hintState = HintStateCreate();
}
parse->hintState->join_hint = list_concat(parse->hintState->join_hint, hint_state->join_hint);
parse->hintState->leading_hint = list_concat(parse->hintState->leading_hint, hint_state->leading_hint);
parse->hintState->row_hint = list_concat(parse->hintState->row_hint, hint_state->row_hint);
parse->hintState->stream_hint = list_concat(parse->hintState->stream_hint, hint_state->stream_hint);
parse->hintState->scan_hint = list_concat(parse->hintState->scan_hint, hint_state->scan_hint);
parse->hintState->hint_warning = list_concat(parse->hintState->hint_warning, hint_state->hint_warning);
parse->hintState->skew_hint = list_concat(parse->hintState->skew_hint, hint_state->skew_hint);
parse->hintState->nall_hints = parse->hintState->nall_hints + hint_state->nall_hints;
parse->hintState->multi_node_hint = hint_state->multi_node_hint;
parse->hintState->sql_ignore_hint = hint_state->sql_ignore_hint;
if (hint_state->block_name_hint) {
BlockNameHint* blockNameHint = (BlockNameHint*)linitial(hint_state->block_name_hint);
append_warning_to_list(
root, (Hint*)blockNameHint, "Hint%s will become invalid due to sub-query pulling up.", hint_string);
hintDelete((Hint*)blockNameHint);
list_free_ext(hint_state->block_name_hint);
hint_state->block_name_hint = NIL;
}
}
static bool is_subquery_partial_push(PlannerInfo* root, RangeTblEntry* rte)
{
if (IS_STREAM_PLAN && !root->parse->can_push && rte->subquery->can_push) {
return true;
}
return false;
}
* pull_up_simple_subquery
* Attempt to pull up a single simple subquery.
*
* jtnode is a RangeTblRef that has been tentatively identified as a simple
* subquery by pull_up_subqueries. We return the replacement jointree node,
* or jtnode itself if we determine that the subquery can't be pulled up after
* all.
*
* rte is the RangeTblEntry referenced by jtnode. Remaining parameters are
* as for pull_up_subqueries_recurse.
*/
static Node* pull_up_simple_subquery(PlannerInfo* root, Node* jtnode, RangeTblEntry* rte, JoinExpr* lowest_outer_join,
JoinExpr *lowest_nulling_outer_join, AppendRelInfo* containing_appendrel)
{
Query* parse = root->parse;
int varno = ((RangeTblRef*)jtnode)->rtindex;
Query* subquery = NULL;
PlannerInfo* subroot = NULL;
int rtoffset;
pullup_replace_vars_context rvcontext;
ListCell* lc = NULL;
if (is_subquery_partial_push(root, rte)) {
return jtnode;
}
root->parse->is_from_subquery_rewrite = true;
* Need a modifiable copy of the subquery to hack on. Even if we didn't
* sometimes choose not to pull up below, we must do this to avoid
* problems if the same subquery is referenced from multiple jointree
* items (which can't happen normally, but might after rule rewriting).
*/
subquery = (Query*)copyObject(rte->subquery);
* Create a PlannerInfo data structure for this subquery.
*
* NOTE: the next few steps should match the first processing in
* subquery_planner(). Can we refactor to avoid code duplication, or
* would that just make things uglier?
*/
subroot = makeNode(PlannerInfo);
subroot->parse = subquery;
subroot->glob = root->glob;
* Set simple subquery as subquery of upper level query and change
* to the same level after pullup
*/
subroot->query_level = root->query_level + 1;
subroot->parent_root = root;
subroot->plan_params = NIL;
subroot->planner_cxt = CurrentMemoryContext;
subroot->init_plans = NIL;
subroot->cte_plan_ids = NIL;
subroot->eq_classes = NIL;
subroot->append_rel_list = NIL;
subroot->rowMarks = NIL;
subroot->hasRecursion = false;
subroot->qualSecurityLevel = 0;
subroot->wt_param_id = -1;
subroot->non_recursive_plan = NULL;
subroot->hasRownumQual = root->hasRownumQual;
Assert(subquery->cteList == NIL);
* If the FROM clause is empty, replace it with a dummy RTE_RESULT RTE, so
* that we don't need so many special cases to deal with that situation.
*/
replace_empty_jointree(subquery);
* Pull up any SubLinks within the subquery's quals, so that we don't
* leave unoptimized SubLinks behind.
*/
if (subquery->hasSubLinks)
pull_up_sublinks(subroot);
* Similarly, inline any set-returning functions in its rangetable.
*/
inline_set_returning_functions(subroot);
* Recursively pull up the subquery's subqueries, so that
* pull_up_subqueries' processing is complete for its jointree and
* rangetable.
*
* Note: we should pass NULL for containing-join info even if we are
* within an outer join in the upper query; the lower query starts with a
* clean slate for outer-join semantics. Likewise, we say we aren't
* handling an appendrel member.
*/
subquery->jointree = (FromExpr*)pull_up_subqueries_recurse(subroot, (Node*)subquery->jointree, NULL, NULL, NULL);
subroot->query_level--;
subroot->parent_root = root->parent_root;
* Now we must recheck whether the subquery is still simple enough to pull
* up. If not, abandon processing it.
*
* We don't really need to recheck all the conditions involved, but it's
* easier just to keep this "if" looking the same as the one in
* pull_up_subqueries_recurse.
*/
if (subquery->jointree == NULL) {
ereport(ERROR,
(errmodule(MOD_OPT),
errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
errmsg("jointree in subquery could not be NULL")));
}
if (is_simple_subquery(subquery, rte, lowest_outer_join) &&
(containing_appendrel == NULL || is_safe_append_member(subquery)) &&
!has_no_expand_hint(subquery)) {
} else {
* Give up, return unmodified RangeTblRef.
*
* Note: The work we just did will be redone when the subquery gets
* planned on its own. Perhaps we could avoid that by storing the
* modified subquery back into the rangetable, but I'm not gonna risk
* it now.
*/
return jtnode;
}
* We must flatten any join alias Vars in the subquery's targetlist,
* because pulling up the subquery's subqueries might have changed their
* expansions into arbitrary expressions, which could affect
* pullup_replace_vars' decisions about whether PlaceHolderVar wrappers
* are needed for tlist entries. (Likely it'd be better to do
* flatten_join_alias_vars on the whole query tree at some earlier stage,
* maybe even in the rewriter; but for now let's just fix this case here.)
*/
subquery->targetList =
(List *)flatten_join_alias_vars(subroot, (Node *)subquery->targetList);
* Adjust level-0 varnos in subquery so that we can append its rangetable
* to upper query's. We have to fix the subquery's append_rel_list as
* well.
*/
rtoffset = list_length(parse->rtable);
OffsetVarNodes((Node*)subquery, rtoffset, 0);
OffsetVarNodes((Node*)subroot->append_rel_list, rtoffset, 0);
if (subquery->hintState) {
pull_up_subquery_hint(root, parse, subquery->hintState);
}
* Upper-level vars in subquery are now one level closer to their parent
* than before.
*/
IncrementVarSublevelsUp((Node*)subquery, -1, 1);
IncrementVarSublevelsUp((Node*)subroot->append_rel_list, -1, 1);
* The subquery's targetlist items are now in the appropriate form to
* insert into the top query, but if we are under an outer join then
* non-nullable items may have to be turned into PlaceHolderVars. If we
* are dealing with an appendrel member then anything that's not a simple
* Var has to be turned into a PlaceHolderVar. Set up appropriate context
* data for pullup_replace_vars.
*/
rvcontext.root = root;
rvcontext.targetlist = subquery->targetList;
rvcontext.target_rte = rte;
if (rte->lateral)
rvcontext.relids = get_relids_in_jointree((Node *) subquery->jointree,
true);
else
rvcontext.relids = NULL;
rvcontext.outer_hasSubLinks = &parse->hasSubLinks;
rvcontext.varno = varno;
rvcontext.need_phvs = (lowest_nulling_outer_join != NULL || containing_appendrel != NULL);
rvcontext.wrap_non_vars = (containing_appendrel != NULL);
rvcontext.rv_cache = (Node**)palloc0((list_length(subquery->targetList) + 1) * sizeof(Node*));
* 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.) We have to use PHVs in the targetList,
* returningList, and havingQual, since those are certainly above any
* outer join. replace_vars_in_jointree tracks its location in the
* jointree and uses PHVs or not appropriately.
*/
parse->targetList = (List*)pullup_replace_vars((Node*)parse->targetList, &rvcontext);
parse->returningList = (List*)pullup_replace_vars((Node*)parse->returningList, &rvcontext);
if (parse->upsertClause != NULL) {
parse->upsertClause->updateTlist = (List*)
pullup_replace_vars((Node*)parse->upsertClause->updateTlist, &rvcontext);
}
replace_vars_in_jointree((Node*)parse->jointree, &rvcontext, lowest_nulling_outer_join);
{
ListCell* l = NULL;
foreach (l, parse->mergeActionList) {
MergeAction* action = (MergeAction*)lfirst(l);
* We only replace targetlist and qual in pgxc and single node mode. For stream
* plan, we don't replace the targetlist and qual, since during plan reference, it'll
* referred to parse->mergeSourceTargetList, which is not replaced in this
* procedure.
* XXXX: Replace the mergeSourceTargetList and then targetlist and qual at the
* same time. However, we need placeholder for this, since for sublink, we'll
* generate different subplans (with different paramid) for different expression,
* and it's also can't be referred.
*/
if (!IS_PGXC_DATANODE && !IS_STREAM_PLAN && !IS_SINGLE_NODE) {
action->targetList = (List*)pullup_replace_vars((Node*)action->targetList, &rvcontext);
action->qual = pullup_replace_vars((Node*)action->qual, &rvcontext);
} else {
action->pulluped_targetList = (List*)pullup_replace_vars((Node*)action->targetList, &rvcontext);
}
}
}
Assert(parse->setOperations == NULL);
parse->havingQual = pullup_replace_vars(parse->havingQual, &rvcontext);
* Replace references in the translated_vars lists of appendrels. When
* pulling up an appendrel member, we do not need PHVs in the list of the
* parent appendrel --- there isn't any outer join between. Elsewhere, use
* PHVs for safety. (This analysis could be made tighter but it seems
* unlikely to be worth much trouble.)
*/
foreach (lc, root->append_rel_list) {
AppendRelInfo* appinfo = (AppendRelInfo*)lfirst(lc);
bool save_need_phvs = rvcontext.need_phvs;
if (appinfo == containing_appendrel)
rvcontext.need_phvs = false;
appinfo->translated_vars = (List*)pullup_replace_vars((Node*)appinfo->translated_vars, &rvcontext);
rvcontext.need_phvs = save_need_phvs;
}
* Replace references in the joinaliasvars lists of join RTEs.
*
* You might think that we could avoid using PHVs for alias vars of joins
* below lowest_outer_join, but that doesn't work because the alias vars
* could be referenced above that join; we need the PHVs to be present in
* such references after the alias vars get flattened. (It might be worth
* trying to be smarter here, someday.)
*/
foreach (lc, parse->rtable) {
RangeTblEntry* otherrte = (RangeTblEntry*)lfirst(lc);
if (otherrte->rtekind == RTE_JOIN)
otherrte->joinaliasvars = (List*)pullup_replace_vars((Node*)otherrte->joinaliasvars, &rvcontext);
}
* If the subquery had a LATERAL marker, propagate that to any of its
* child RTEs that could possibly now contain lateral cross-references.
* The children might or might not contain any actual lateral
* cross-references, but we have to mark the pulled-up child RTEs so that
* later planner stages will check for such.
*
* NB: although the parser only sets the lateral flag in subquery and
* function RTEs, after this step it can also be set in VALUES RTEs.
*/
if (rte->lateral)
{
foreach(lc, subquery->rtable)
{
RangeTblEntry *child_rte = (RangeTblEntry *) lfirst(lc);
switch (child_rte->rtekind)
{
case RTE_SUBQUERY:
case RTE_FUNCTION:
case RTE_VALUES:
child_rte->lateral = true;
break;
case RTE_RELATION:
case RTE_JOIN:
case RTE_CTE:
case RTE_RESULT:
case RTE_REMOTE_DUMMY:
#ifdef USE_SPQ
case RTE_VOID:
case RTE_TABLEFUNCTION:
#endif
break;
}
}
}
foreach(lc, subquery->rtable) {
RangeTblEntry *rte = (RangeTblEntry *)lfirst(lc);
rte->pulled_from_subquery = true;
}
* 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 = list_concat(parse->rtable, subquery->rtable);
rte->subquery_pull_up = true;
* Pull up any FOR UPDATE/SHARE markers, too. (OffsetVarNodes already
* adjusted the marker rtindexes, so just concat the lists.)
*/
parse->rowMarks = list_concat(parse->rowMarks, subquery->rowMarks);
* We also have to fix the relid sets of any PlaceHolderVar nodes in the
* parent query. (This could perhaps be done by pullup_replace_vars(),
* but it seems cleaner to use two passes.) Note in particular that any
* PlaceHolderVar nodes just created by pullup_replace_vars() 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 subrelids
* into the single-slot AppendRelInfo structs.
*/
if (parse->hasSubLinks || root->glob->lastPHId != 0 || root->append_rel_list) {
Relids subrelids;
subrelids = get_relids_in_jointree((Node*)subquery->jointree, false);
substitute_multiple_relids((Node*)parse, varno, subrelids);
fix_append_rel_relids(root->append_rel_list, varno, subrelids);
}
* And now add subquery's AppendRelInfos to our list.
*/
root->append_rel_list = list_concat(root->append_rel_list, subroot->append_rel_list);
* We don't have to do the equivalent bookkeeping for outer-join info,
* because that hasn't been set up yet. placeholder_list likewise.
*/
Assert(root->join_info_list == NIL);
Assert(subroot->join_info_list == NIL);
Assert(root->lateral_info_list == NIL);
Assert(subroot->lateral_info_list == NIL);
Assert(root->placeholder_list == NIL);
Assert(subroot->placeholder_list == NIL);
* Miscellaneous housekeeping.
*
* Although replace_rte_variables() faithfully updated parse->hasSubLinks
* if it copied any SubLinks out of the subquery's targetlist, we still
* could have SubLinks added to the query in the expressions of FUNCTION
* and VALUES RTEs copied up from the subquery. So it's necessary to copy
* subquery->hasSubLinks anyway. Perhaps this can be improved someday.
*/
parse->hasSubLinks = parse->hasSubLinks || subquery->hasSubLinks;
parse->hasRowSecurity = parse->hasRowSecurity || subquery->hasRowSecurity;
* subquery won't be pulled up if it hasAggs or hasWindowFuncs, or
* hasTargetSRFs, so no work needed on those flags
*
* Return the adjusted subquery jointree to replace the RangeTblRef entry
* in parent's jointree; or, if the FromExpr is degenerate, just return
* its single member.
*/
Assert(IsA(subquery->jointree, FromExpr));
Assert(subquery->jointree->fromlist != NIL);
if (subquery->jointree->quals == NULL &&
list_length(subquery->jointree->fromlist) == 1)
return (Node *) linitial(subquery->jointree->fromlist);
return (Node*)subquery->jointree;
}
* pull_up_simple_union_all
* Pull up a single simple UNION ALL subquery.
*
* jtnode is a RangeTblRef that has been identified as a simple UNION ALL
* subquery by pull_up_subqueries. We pull up the leaf subqueries and
* build an "append relation" for the union set. The result value is just
* jtnode, since we don't actually need to change the query jointree.
*/
static Node* pull_up_simple_union_all(PlannerInfo* root, Node* jtnode, RangeTblEntry* rte)
{
int varno = ((RangeTblRef*)jtnode)->rtindex;
Query* subquery = rte->subquery;
int rtoffset;
List* rtable = NIL;
UNIONALL_SHIPPING_TYPE shipping_type = SHIPPING_NONE;
if (subquery->setOperations == NULL) {
elog(ERROR, "subquery's setOperations tree should not be NULL in pull_up_simple_union_all");
}
if (IS_STREAM_PLAN) {
shipping_type = precheck_shipping_union_all(subquery, subquery->setOperations);
if (shipping_type == SHIPPING_ALL && subquery->can_push == false) {
shipping_type = SHIPPING_PARTIAL;
}
if (shipping_type == SHIPPING_ALL) {
if (!root->parse->can_push) {
return jtnode;
}
} else if (shipping_type == SHIPPING_PARTIAL) {
return jtnode;
} else {
if (root->parse->can_push && check_base_rel_in_fromlist(root->parse, jtnode)) {
return jtnode;
}
}
}
* Append child RTEs to parent rtable.
*
* Upper-level vars in subquery are now one level closer to their parent
* than before. We don't have to worry about offsetting varnos, though,
* because any such vars must refer to stuff above the level of the query
* we are pulling into.
*/
rtoffset = list_length(root->parse->rtable);
rtable = (List*)copyObject(subquery->rtable);
IncrementVarSublevelsUp_rtable(rtable, -1, 1);
ListCell *lc= NULL;
foreach (lc, rtable){
RangeTblEntry* rte = (RangeTblEntry*)lfirst(lc);
if (rte->rtekind == RTE_SUBQUERY) {
rte->pulled_from_subquery = true;
}
}
root->parse->rtable = list_concat(root->parse->rtable, rtable);
rte->subquery_pull_up = true;
* Recursively scan the subquery's setOperations tree and add
* AppendRelInfo nodes for leaf subqueries to the parent's
* append_rel_list. Also apply pull_up_subqueries to the leaf subqueries.
*/
AssertEreport(subquery->setOperations != NULL,
MOD_OPT_REWRITE,
"subquery's setOperations tree should not be NULL in pull_up_simple_union_all");
pull_up_union_leaf_queries(subquery->setOperations, root, varno, subquery, rtoffset);
* Mark the parent as an append relation.
*/
rte->inh = true;
if (IS_STREAM_PLAN && root->parse->can_push) {
if (shipping_type == SHIPPING_NONE && check_base_rel_in_fromlist(root->parse, jtnode))
set_stream_off();
}
return jtnode;
}
* pull_up_union_leaf_queries -- recursive guts of pull_up_simple_union_all
*
* Build an AppendRelInfo for each leaf query in the setop tree, and then
* apply pull_up_subqueries to the leaf query.
*
* Note that setOpQuery is the Query containing the setOp node, whose tlist
* contains references to all the setop output columns. When called from
* pull_up_simple_union_all, this is *not* the same as root->parse, which is
* the parent Query we are pulling up into.
*
* parentRTindex is the appendrel parent's index in root->parse->rtable.
*
* The child RTEs have already been copied to the parent. childRToffset
* tells us where in the parent's range table they were copied. When called
* from flatten_simple_union_all, childRToffset is 0 since the child RTEs
* were already in root->parse->rtable and no RT index adjustment is needed.
*/
static void pull_up_union_leaf_queries(
Node* setOp, PlannerInfo* root, int parentRTindex, Query* setOpQuery, int childRToffset)
{
if (IsA(setOp, RangeTblRef)) {
RangeTblRef* rtr = (RangeTblRef*)setOp;
int childRTindex;
AppendRelInfo* appinfo = NULL;
* Calculate the index in the parent's range table
*/
childRTindex = childRToffset + rtr->rtindex;
* Build a suitable AppendRelInfo, and attach to parent's list.
*/
appinfo = makeNode(AppendRelInfo);
appinfo->parent_relid = parentRTindex;
appinfo->child_relid = childRTindex;
appinfo->parent_reltype = InvalidOid;
appinfo->child_reltype = InvalidOid;
make_setop_translation_list(setOpQuery, childRTindex, &appinfo->translated_vars);
appinfo->parent_reloid = InvalidOid;
root->append_rel_list = lappend(root->append_rel_list, appinfo);
* Recursively apply pull_up_subqueries to the new child RTE. (We
* must build the AppendRelInfo first, because this will modify it.)
* Note that we can pass NULL for containing-join info even if we're
* actually under an outer join, because the child's expressions
* aren't going to propagate up above the join.
*/
rtr = makeNode(RangeTblRef);
rtr->rtindex = childRTindex;
(void)pull_up_subqueries_recurse(root, (Node*)rtr, NULL, NULL, appinfo);
} else if (IsA(setOp, SetOperationStmt)) {
SetOperationStmt* op = (SetOperationStmt*)setOp;
pull_up_union_leaf_queries(op->larg, root, parentRTindex, setOpQuery, childRToffset);
pull_up_union_leaf_queries(op->rarg, root, parentRTindex, setOpQuery, childRToffset);
} else {
ereport(ERROR,
(errmodule(MOD_OPT),
errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE),
errmsg("unrecognized node type: %d", (int)nodeTag(setOp))));
}
}
* make_setop_translation_list
* Build the list of translations from parent Vars to child Vars for
* a UNION ALL member. (At this point it's just a simple list of
* referencing Vars, but if we succeed in pulling up the member
* subquery, the Vars will get replaced by pulled-up expressions.)
*/
static void make_setop_translation_list(Query* query, Index newvarno, List** translated_vars)
{
List* vars = NIL;
ListCell* l = NULL;
foreach (l, query->targetList) {
TargetEntry* tle = (TargetEntry*)lfirst(l);
if (tle->resjunk)
continue;
vars = lappend(vars, makeVarFromTargetEntry(newvarno, tle));
}
*translated_vars = vars;
}
* is_simple_lateral_subquery
* If the subquery is LATERAL, check for pullup restrictions from that.
*/
static bool is_simple_lateral_subquery(Query* subquery, JoinExpr *lowest_outer_join)
{
bool restricted = false;
Relids safe_upper_varnos = NULL;
* The subquery's WHERE and JOIN/ON quals mustn't contain any lateral
* references to rels outside a higher outer join (including the case
* where the outer join is within the subquery itself). In such a
* case, pulling up would result in a situation where we need to
* postpone quals from below an outer join to above it, which is
* probably completely wrong and in any case is a complication that
* doesn't seem worth addressing at the moment.
*/
if (lowest_outer_join != NULL)
{
restricted = true;
safe_upper_varnos = get_relids_in_jointree((Node *) lowest_outer_join,
true);
}
else
{
restricted = false;
safe_upper_varnos = NULL;
}
if (jointree_contains_lateral_outer_refs((Node *) subquery->jointree,
restricted, safe_upper_varnos))
return false;
* If there's an outer join above the LATERAL subquery, also disallow
* pullup if the subquery's targetlist has any references to rels
* outside the outer join, since these might get pulled into quals
* above the subquery (but in or below the outer join) and then lead
* to qual-postponement issues similar to the case checked for above.
* (We wouldn't need to prevent pullup if no such references appear in
* outer-query quals, but we don't have enough info here to check
* that. Also, maybe this restriction could be removed if we forced
* such refs to be wrapped in PlaceHolderVars, even when they're below
* the nearest outer join? But it's a pretty hokey usage, so not
* clear this is worth sweating over.)
*/
if (lowest_outer_join != NULL)
{
Relids lvarnos = pull_varnos_of_level((Node *) subquery->targetList, 1);
if (!bms_is_subset(lvarnos, safe_upper_varnos))
return false;
}
return true;
}
static bool is_grouping_subquery(Query* subquery)
{
* Can't pull up a subquery involving grouping, aggregation, sorting,
* limiting, or WITH. (XXX WITH could possibly be allowed later)
*
* We also don't pull up a subquery that has explicit FOR UPDATE/SHARE
* clauses, because pullup would cause the locking to occur semantically
* higher than it should. Implicit FOR UPDATE/SHARE is okay because in
* that case the locking was originally declared in the upper query
* anyway.
*/
if (subquery->hasAggs || subquery->hasWindowFuncs || subquery->groupClause || subquery->groupingSets ||
subquery->havingQual || subquery->sortClause || subquery->distinctClause || subquery->limitOffset ||
subquery->limitCount || subquery->hasForUpdate || subquery->cteList)
return false;
return true;
}
* is_simple_subquery
* Check a subquery in the range table to see if it's simple enough
* to pull up into the parent query.
* rte is the RTE_SUBQUERY RangeTblEntry that contained the subquery.
* (Note subquery is not necessarily equal to rte->subquery; it could be a
* processed copy of that.)
* lowest_outer_join is the lowest outer join above the subquery, or NULL.
*/
static bool is_simple_subquery(Query* subquery, RangeTblEntry *rte, JoinExpr *lowest_outer_join)
{
* Let's just make sure it's a valid subselect ...
*/
if (!IsA(subquery, Query) || subquery->commandType != CMD_SELECT || subquery->utilityStmt != NULL)
ereport(
ERROR, (errmodule(MOD_OPT), errcode(ERRCODE_OPTIMIZER_INCONSISTENT_STATE), (errmsg("subquery is bogus"))));
* Can't currently pull up a query with setops (unless it's simple UNION
* ALL, which is handled by a different code path). Maybe after querytree
* redesign...
*/
if (subquery->setOperations)
return false;
if (!is_grouping_subquery(subquery))
return false;
* Don't pull up if the RTE represents a security-barrier view; we couldn't
* prevent information leakage once the RTE's Vars are scattered about in
* the upper query.
*/
if (rte->security_barrier)
return false;
if (ContainRownumQual(subquery)) {
return false;
}
if (subquery->hasAggs || subquery->hasWindowFuncs || subquery->groupClause || subquery->groupingSets ||
subquery->havingQual || subquery->sortClause || subquery->distinctClause || subquery->limitOffset ||
subquery->limitCount || subquery->hasForUpdate || subquery->cteList)
return false;
if (subquery->is_flt_frame && subquery->hasTargetSRFs) {
return false;
}
* If the subquery is LATERAL, check for pullup restrictions from that.
*/
if (rte->lateral &&
!is_simple_lateral_subquery(subquery, lowest_outer_join))
{
return false;
}
#ifndef ENABLE_MULTIPLE_NODES
if (ContainRownumQual(subquery)) {
return false;
}
#endif
* 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 volatile functions in its
* targetlist. Otherwise we might introduce multiple evaluations of these
* functions, if they get copied to multiple places in the upper query,
* leading to surprising results. (Note: the PlaceHolderVar mechanism
* doesn't quite guarantee single evaluation; else we could pull up anyway
* and just wrap such items in PlaceHolderVars ...)
*/
if (contain_volatile_functions((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. It would pose a
* problem for the PlaceHolderVar mechanism too, since we'd have no way to
* identify where to evaluate a PHV coming out of the subquery. Not worth
* working hard on this, just to collapse SubqueryScan/Result into Result;
* especially since the SubqueryScan can often be optimized away by
* setrefs.c anyway.
*/
if (subquery->jointree->fromlist == NIL)
return false;
return true;
}
* is_simple_union_all
* Check a subquery to see if it's a simple UNION ALL.
*
* We require all the setops to be UNION ALL (no mixing) and there can't be
* any datatype coercions involved, ie, all the leaf queries must emit the
* same datatypes.
*/
static bool is_simple_union_all(Query* subquery)
{
SetOperationStmt* topop = NULL;
if (!IsA(subquery, Query) || subquery->commandType != CMD_SELECT || subquery->utilityStmt != NULL)
ereport(
ERROR, (errmodule(MOD_OPT), errcode(ERRCODE_OPTIMIZER_INCONSISTENT_STATE), (errmsg("subquery is bogus"))));
topop = (SetOperationStmt*)subquery->setOperations;
if (topop == NULL)
return false;
AssertEreport(
IsA(topop, SetOperationStmt), MOD_OPT_REWRITE, "subquery's setOperations mismatch in is_simple_union_all");
#ifndef ENABLE_MULTIPLE_NODES
if (ContainRownumQual(subquery)) {
return false;
}
#endif
if (subquery->sortClause || subquery->limitOffset || subquery->limitCount || subquery->rowMarks ||
subquery->cteList)
return false;
return is_simple_union_all_recurse((Node*)topop, subquery, topop->colTypes);
}
static bool is_simple_union_all_recurse(Node* setOp, Query* setOpQuery, List* colTypes)
{
if (IsA(setOp, RangeTblRef)) {
RangeTblRef* rtr = (RangeTblRef*)setOp;
RangeTblEntry* rte = rt_fetch(rtr->rtindex, setOpQuery->rtable);
Query* subquery = rte->subquery;
AssertEreport(subquery != NULL, MOD_OPT_REWRITE, "subquery should not be NULL in is_simple_union_all_recurse");
return tlist_same_datatypes(subquery->targetList, colTypes, true);
} else if (IsA(setOp, SetOperationStmt)) {
SetOperationStmt* op = (SetOperationStmt*)setOp;
if (op->op != SETOP_UNION || !op->all)
return false;
return is_simple_union_all_recurse(op->larg, setOpQuery, colTypes) &&
is_simple_union_all_recurse(op->rarg, setOpQuery, colTypes);
} else {
ereport(ERROR,
(errmodule(MOD_OPT),
errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE),
errmsg("unrecognized node type: %d", (int)nodeTag(setOp))));
return false;
}
}
* is_safe_append_member
* Check a subquery that is a leaf of a UNION ALL appendrel to see if it's
* safe to pull up.
*/
static bool is_safe_append_member(Query* subquery)
{
FromExpr* jtnode = NULL;
* It's only safe to pull up the child if its jointree contains exactly
* one RTE, else the AppendRelInfo data structure breaks. The one base RTE
* could be buried in several levels of FromExpr, however.
*
* Also, the child can't have any WHERE quals because there's no place to
* put them in an appendrel. (This is a bit annoying...) If we didn't
* need to check this, we'd just test whether get_relids_in_jointree()
* yields a singleton set, to be more consistent with the coding
* of fix_append_rel_relids().
*/
jtnode = subquery->jointree;
while (IsA(jtnode, FromExpr)) {
if (jtnode->quals != NULL)
return false;
if (list_length(jtnode->fromlist) != 1)
return false;
jtnode = (FromExpr*)linitial(jtnode->fromlist);
}
if (!IsA(jtnode, RangeTblRef))
return false;
if (subquery->hintState)
return false;
return true;
}
* jointree_contains_lateral_outer_refs
* Check for disallowed lateral references in a jointree's quals
*
* If restricted is false, all level-1 Vars are allowed (but we still must
* search the jointree, since it might contain outer joins below which there
* will be restrictions). If restricted is true, return TRUE when any qual
* in the jointree contains level-1 Vars coming from outside the rels listed
* in safe_upper_varnos.
*/
static bool
jointree_contains_lateral_outer_refs(Node *jtnode, bool restricted,
Relids safe_upper_varnos)
{
if (jtnode == NULL)
return false;
if (IsA(jtnode, RangeTblRef))
return false;
else if (IsA(jtnode, FromExpr))
{
FromExpr *f = (FromExpr *) jtnode;
ListCell *l = NULL;
foreach(l, f->fromlist)
{
if (jointree_contains_lateral_outer_refs((Node *)lfirst(l),
restricted,
safe_upper_varnos))
return true;
}
if (restricted &&
!bms_is_subset(pull_varnos_of_level(f->quals, 1),
safe_upper_varnos))
return true;
}
else if (IsA(jtnode, JoinExpr))
{
JoinExpr *j = (JoinExpr *) jtnode;
* If this is an outer join, we mustn't allow any upper lateral
* references in or below it.
*/
if (j->jointype != JOIN_INNER)
{
restricted = true;
safe_upper_varnos = NULL;
}
if (jointree_contains_lateral_outer_refs(j->larg,
restricted,
safe_upper_varnos))
return true;
if (jointree_contains_lateral_outer_refs(j->rarg,
restricted,
safe_upper_varnos))
return true;
if (restricted &&
!bms_is_subset(pull_varnos_of_level(j->quals, 1),
safe_upper_varnos))
return true;
}
else
elog(ERROR, "unrecognized node type: %d",
(int) nodeTag(jtnode));
return false;
}
* Helper routine for pull_up_subqueries: do pullup_replace_vars on every
* expression in the jointree, without changing the jointree structure itself.
* Ugly, but there's no other way...
*
* If we are at or below lowest_nulling_outer_join, we can suppress use of
* PlaceHolderVars wrapped around the replacement expressions.
*/
static void replace_vars_in_jointree(Node* jtnode, pullup_replace_vars_context* context, JoinExpr* lowest_nulling_outer_join)
{
if (jtnode == NULL)
return;
if (IsA(jtnode, RangeTblRef)) {
* If the RangeTblRef refers to a LATERAL subquery (that isn't the
* same subquery we're pulling up), it might contain references to the
* target subquery, which we must replace. We drive this from the
* jointree scan, rather than a scan of the rtable, for a couple of
* reasons: we can avoid processing no-longer-referenced RTEs, and we
* can use the appropriate setting of need_phvs depending on whether
* the RTE is above possibly-nulling outer joins or not.
*/
int varno = ((RangeTblRef *) jtnode)->rtindex;
if (varno != context->varno)
{
RangeTblEntry *rte = rt_fetch(varno, context->root->parse->rtable);
Assert(rte != context->target_rte);
if (rte->lateral)
{
switch (rte->rtekind)
{
case RTE_SUBQUERY:
rte->subquery =
pullup_replace_vars_subquery(rte->subquery,
context);
break;
case RTE_FUNCTION:
#ifdef USE_SPQ
case RTE_TABLEFUNCTION:
#endif
rte->funcexpr =
pullup_replace_vars(rte->funcexpr,
context);
break;
case RTE_VALUES:
rte->values_lists = (List *)
pullup_replace_vars((Node *) rte->values_lists,
context);
break;
case RTE_RELATION:
case RTE_JOIN:
case RTE_CTE:
case RTE_RESULT:
#ifdef USE_SPQ
case RTE_VOID:
#endif
Assert(false);
break;
#ifdef PGXC
case RTE_REMOTE_DUMMY:
break;
#endif
}
}
}
} else if (IsA(jtnode, FromExpr)) {
FromExpr* f = (FromExpr*)jtnode;
ListCell* l = NULL;
foreach (l, f->fromlist)
replace_vars_in_jointree((Node*)lfirst(l), context, lowest_nulling_outer_join);
f->quals = pullup_replace_vars(f->quals, context);
} else if (IsA(jtnode, JoinExpr)) {
JoinExpr* j = (JoinExpr*)jtnode;
bool save_need_phvs = context->need_phvs;
if (j == lowest_nulling_outer_join) {
context->need_phvs = false;
lowest_nulling_outer_join = NULL;
}
replace_vars_in_jointree(j->larg, context, lowest_nulling_outer_join);
replace_vars_in_jointree(j->rarg, context, lowest_nulling_outer_join);
* Use PHVs within the join quals of a full join, even when it's the
* lowest nulling outer join. Otherwise, we cannot identify which
* side of the join a pulled-up var-free expression came from, which
* can lead to failure to make a plan at all because none of the quals
* appear to be mergeable or hashable conditions. For this purpose we
* don't care about the state of wrap_non_vars, so leave it alone.
*/
if (j->jointype == JOIN_FULL) {
context->need_phvs = true;
}
j->quals = pullup_replace_vars(j->quals, context);
* We don't bother to update the colvars list, since it won't be used
* again ...
*/
context->need_phvs = save_need_phvs;
} else {
ereport(ERROR,
(errmodule(MOD_OPT),
errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE),
errmsg("unrecognized node type: %d", (int)nodeTag(jtnode))));
}
}
* Apply pullup variable replacement throughout an expression tree
*
* Returns a modified copy of the tree, so this can't be used where we
* need to do in-place replacement.
*/
static Node* pullup_replace_vars(Node* expr, pullup_replace_vars_context* context)
{
return replace_rte_variables(
expr, context->varno, 0, pullup_replace_vars_callback, (void*)context, context->outer_hasSubLinks);
}
static Node* pullup_replace_vars_callback(Var* var, replace_rte_variables_context* context)
{
pullup_replace_vars_context* rcon = (pullup_replace_vars_context*)context->callback_arg;
int varattno = var->varattno;
Node* newnode = NULL;
* If PlaceHolderVars are needed, we cache the modified expressions in
* rcon->rv_cache[]. This is not in hopes of any material speed gain
* within this function, but to avoid generating identical PHVs with
* different IDs. That would result in duplicate evaluations at runtime,
* and possibly prevent optimizations that rely on recognizing different
* references to the same subquery output as being equal(). So it's worth
* a bit of extra effort to avoid it.
*/
if (rcon->need_phvs && varattno >= InvalidAttrNumber && varattno <= list_length(rcon->targetlist) &&
rcon->rv_cache[varattno] != NULL) {
newnode = (Node*)copyObject(rcon->rv_cache[varattno]);
} else if (varattno == InvalidAttrNumber) {
RowExpr* rowexpr = NULL;
List* colnames = NIL;
List* fields = NIL;
bool save_need_phvs = rcon->need_phvs;
int save_sublevelsup = context->sublevels_up;
* If generating an expansion for a var of a named rowtype (ie, this
* is a plain relation RTE), then we must include dummy items for
* dropped columns. If the var is RECORD (ie, this is a JOIN), then
* omit dropped columns. Either way, attach column names to the
* RowExpr for use of ruleutils.c.
*
* In order to be able to cache the results, we always generate the
* expansion with varlevelsup = 0, and then adjust if needed.
*/
expandRTE(rcon->target_rte,
var->varno,
0 ,
var->location,
(var->vartype != RECORDOID),
&colnames,
&fields);
rcon->need_phvs = false;
context->sublevels_up = 0;
fields = (List*)replace_rte_variables_mutator((Node*)fields, context);
rcon->need_phvs = save_need_phvs;
context->sublevels_up = save_sublevelsup;
rowexpr = makeNode(RowExpr);
rowexpr->args = fields;
rowexpr->row_typeid = var->vartype;
rowexpr->row_format = COERCE_IMPLICIT_CAST;
rowexpr->colnames = colnames;
rowexpr->location = var->location;
newnode = (Node*)rowexpr;
* Insert PlaceHolderVar if needed. Notice that we are wrapping one
* PlaceHolderVar around the whole RowExpr, rather than putting one
* around each element of the row. This is because we need the
* expression to yield NULL, not ROW(NULL,NULL,...) when it is forced
* to null by an outer join.
*/
if (rcon->need_phvs) {
newnode = (Node*)make_placeholder_expr(rcon->root, (Expr*)newnode, bms_make_singleton(rcon->varno));
rcon->rv_cache[InvalidAttrNumber] = (Node*)copyObject(newnode);
}
}
#ifdef PGXC
else if (varattno == XC_NodeIdAttributeNumber) {
newnode = NULL;
}
#endif
else {
TargetEntry* tle = get_tle_by_resno(rcon->targetlist, varattno);
if (tle == NULL)
ereport(ERROR,
(errmodule(MOD_OPT),
errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
(errmsg("could not find attribute %d in subquery targetlist", varattno))));
newnode = (Node*)copyObject(tle->expr);
if (rcon->need_phvs) {
bool wrap = false;
if (newnode && IsA(newnode, Var) && ((Var*)newnode)->varlevelsup == 0) {
* Simple Vars always escape being wrapped, unless they are
* lateral references to something outside the subquery being
* pulled up. (Even then, we could omit the PlaceHolderVar if
* the referenced rel is under the same lowest outer join, but
* it doesn't seem worth the trouble to check that.)
*/
if (rcon->target_rte->lateral && !bms_is_member(((Var *) newnode)->varno, rcon->relids))
wrap = true;
else
wrap = false;
} else if (newnode && IsA(newnode, PlaceHolderVar) && ((PlaceHolderVar*)newnode)->phlevelsup == 0) {
wrap = false;
} else if (rcon->wrap_non_vars) {
wrap = true;
} else {
* If it contains a Var of the subquery being pulled up, and
* does not contain any non-strict constructs, then it's
* certainly nullable so we don't need to insert a
* PlaceHolderVar.
*
* This analysis could be tighter: in particular, a non-strict
* construct hidden within a lower-level PlaceHolderVar is not
* reason to add another PHV. But for now it doesn't seem
* worth the code to be more exact.
*
* Note: in future maybe we should insert a PlaceHolderVar
* anyway, if the tlist item is expensive to evaluate?
*
* For a LATERAL subquery, we have to check the actual var
* membership of the node, but if it's non-lateral then any
* level-zero var must belong to the subquery.
*/
if ((rcon->target_rte->lateral ?
bms_overlap(pull_varnos((Node *) newnode), rcon->relids) :
contain_vars_of_level((Node *) newnode, 0)) &&
!contain_nonstrict_functions((Node *) newnode)) {
wrap = false;
} else {
wrap = true;
}
}
if (wrap)
newnode = (Node*)make_placeholder_expr(rcon->root, (Expr*)newnode, bms_make_singleton(rcon->varno));
* Cache it if possible (ie, if the attno is in range, which it
* probably always should be). We can cache the value even if we
* decided we didn't need a PHV, since this result will be
* suitable for any request that has need_phvs.
*/
if (varattno > InvalidAttrNumber && varattno <= list_length(rcon->targetlist))
rcon->rv_cache[varattno] = (Node*)copyObject(newnode);
}
}
if (var->varlevelsup > 0)
IncrementVarSublevelsUp(newnode, var->varlevelsup, 0);
return newnode;
}
* Apply pullup variable replacement to a subquery
*
* This needs to be different from pullup_replace_vars() because
* replace_rte_variables will think that it shouldn't increment sublevels_up
* before entering the Query; so we need to call it with sublevels_up == 1.
*/
static Query *
pullup_replace_vars_subquery(Query *query,
pullup_replace_vars_context *context)
{
Assert(IsA(query, Query));
return (Query *) replace_rte_variables((Node *) query,
context->varno, 1,
pullup_replace_vars_callback,
(void *) context,
NULL);
}
* flatten_simple_union_all
* Try to optimize top-level UNION ALL structure into an appendrel
*
* If a query's setOperations tree consists entirely of simple UNION ALL
* operations, flatten it into an append relation, which we can process more
* intelligently than the general setops case. Otherwise, do nothing.
*
* In most cases, this can succeed only for a top-level query, because for a
* subquery in FROM, the parent query's invocation of pull_up_subqueries would
* already have flattened the UNION via pull_up_simple_union_all. But there
* are a few cases we can support here but not in that code path, for example
* when the subquery also contains ORDER BY.
*/
void flatten_simple_union_all(PlannerInfo* root)
{
Query* parse = root->parse;
SetOperationStmt* topop = NULL;
Node* leftmostjtnode = NULL;
int leftmostRTI = 0;
RangeTblEntry* leftmostRTE = NULL;
int childRTI;
RangeTblEntry* childRTE = NULL;
RangeTblRef* rtr = NULL;
topop = (SetOperationStmt*)parse->setOperations;
AssertEreport(topop != NULL && IsA(topop, SetOperationStmt),
MOD_OPT_REWRITE,
"SetOperationStmt shouldn't be NULL in flatten_simple_union_all");
if (root->hasRecursion)
return;
* Recursively check the tree of set operations. If not all UNION ALL
* with identical column types, punt.
*
* In multi-node group scenario, we should not flatten union all because
* the branchs may be in different node group, we could not determine the
* group for append path
*/
if (!is_simple_union_all_recurse((Node*)topop, parse, topop->colTypes) || ng_is_multiple_nodegroup_scenario())
return;
* Locate the leftmost leaf query in the setops tree. The upper query's
* Vars all refer to this RTE (see transformSetOperationStmt).
*/
leftmostjtnode = topop->larg;
while (leftmostjtnode && IsA(leftmostjtnode, SetOperationStmt))
leftmostjtnode = ((SetOperationStmt*)leftmostjtnode)->larg;
if (leftmostjtnode && IsA(leftmostjtnode, RangeTblRef)) {
leftmostRTI = ((RangeTblRef*)leftmostjtnode)->rtindex;
leftmostRTE = rt_fetch(leftmostRTI, parse->rtable);
AssertEreport(leftmostRTE->rtekind == RTE_SUBQUERY,
MOD_OPT_REWRITE,
"leftmostRTE should be SUBQUERY in flatten_simple_union_all");
} else {
ereport(ERROR,
(errmodule(MOD_OPT), errcode(ERRCODE_OPTIMIZER_INCONSISTENT_STATE), (errmsg("RangeTblRef not found."))));
}
* Make a copy of the leftmost RTE and add it to the rtable. This copy
* will represent the leftmost leaf query in its capacity as a member of
* the appendrel. The original will represent the appendrel as a whole.
* (We must do things this way because the upper query's Vars have to be
* seen as referring to the whole appendrel.)
*/
childRTE = (RangeTblEntry*)copyObject(leftmostRTE);
parse->rtable = lappend(parse->rtable, childRTE);
childRTI = list_length(parse->rtable);
((RangeTblRef*)leftmostjtnode)->rtindex = childRTI;
leftmostRTE->inh = true;
* Form a RangeTblRef for the appendrel, and insert it into FROM. The top
* Query of a setops tree should have had an empty FromClause initially.
*/
rtr = makeNode(RangeTblRef);
rtr->rtindex = leftmostRTI;
AssertEreport(parse->jointree->fromlist == NIL,
MOD_OPT_REWRITE,
"The top Query of a setops tree should have had an empty FromClause in flatten_simple_union_all");
parse->jointree->fromlist = list_make1(rtr);
* Now pretend the query has no setops. We must do this before trying to
* do subquery pullup, because of Assert in pull_up_simple_subquery.
*/
parse->setOperations = NULL;
* Build AppendRelInfo information, and apply pull_up_subqueries to the
* leaf queries of the UNION ALL. (We must do that now because they
* weren't previously referenced by the jointree, and so were missed by
* the main invocation of pull_up_subqueries.)
*/
pull_up_union_leaf_queries((Node*)topop, root, leftmostRTI, parse, 0);
}
* @Description: Delete not Null Test if var type have not null constraint.
* @in node: Qual cluase.
* @in qry: Query tree.
* @return: return the remaining node.
*/
static Node* deleteRelatedNullTest(Node* node, PlannerInfo* root)
{
if (node == NULL) {
return NULL;
}
if (or_clause(node)) {
BoolExpr* bool_node = (BoolExpr*)node;
ListCell* cell = NULL;
foreach (cell, bool_node->args) {
* If or clause exists 'not null test' can be deleted, then this or clause can all deleted.
* That is bescuse 'not null test' is always true.
*/
Node* result = deleteRelatedNullTest((Node*)lfirst(cell), root);
if (result == NULL) {
return NULL;
}
}
} else if (and_clause(node)) {
BoolExpr* bool_node = (BoolExpr*)node;
bool_node->args = (List*)deleteRelatedNullTest((Node*)bool_node->args, root);
* If and clause exists 'not null test' BOTH can be deleted, then this and clause can be deleted.
* That is bescuse BOTH 'not null test' are always true.
*/
if (bool_node->args == NULL)
return NULL;
} else if (IsA(node, List)) {
List* args_list = NIL;
List* l = (List*)node;
ListCell* cell = NULL;
foreach (cell, l) {
Node* result = deleteRelatedNullTest((Node*)lfirst(cell), root);
if (result != NULL) {
args_list = lappend(args_list, result);
}
}
return (Node*)args_list;
} else if (IsA(node, NullTest)) {
NullTest* NullExpr = (NullTest*)node;
if (IS_NOT_NULL == NullExpr->nulltesttype && IsA(NullExpr->arg, Var)) {
Var* var = (Var*)NullExpr->arg;
if (check_var_nonnullable(root->parse, (Node*)var)) {
return NULL;
}
}
}
return node;
}
* @Description: Delete related NullTest.
* @in parse: The Query Tree after parsing for SQL.
*/
void removeNotNullTest(PlannerInfo* root)
{
Query* parse = root->parse;
if (list_length(parse->rtable) == 1) {
RangeTblEntry* rte = (RangeTblEntry*)linitial(parse->rtable);
if (rte->rtekind == RTE_RELATION) {
parse->jointree->quals = deleteRelatedNullTest(parse->jointree->quals, root);
}
}
}
* reduce_outer_joins
* Attempt to reduce outer joins to plain inner joins.
*
* The idea here is that given a query like
* SELECT ... FROM a LEFT JOIN b ON (...) WHERE b.y = 42;
* we can reduce the LEFT JOIN to a plain JOIN if the "=" operator in WHERE
* is strict. The strict operator will always return NULL, causing the outer
* WHERE to fail, on any row where the LEFT JOIN filled in NULLs for b's
* columns. Therefore, there's no need for the join to produce null-extended
* rows in the first place --- which makes it a plain join not an outer join.
* (This scenario may not be very likely in a query written out by hand, but
* it's reasonably likely when pushing quals down into complex views.)
*
* More generally, an outer join can be reduced in strength if there is a
* strict qual above it in the qual tree that constrains a Var from the
* nullable side of the join to be non-null. (For FULL joins this applies
* to each side separately.)
*
* Another transformation we apply here is to recognize cases like
* SELECT ... FROM a LEFT JOIN b ON (a.x = b.y) WHERE b.y IS NULL;
* If the join clause is strict for b.y, then only null-extended rows could
* pass the upper WHERE, and we can conclude that what the query is really
* specifying is an anti-semijoin. We change the join type from JOIN_LEFT
* to JOIN_ANTI. The IS NULL clause then becomes redundant, and must be
* removed to prevent bogus selectivity calculations, but we leave it to
* distribute_qual_to_rels to get rid of such clauses.
*
* Also, we get rid of JOIN_RIGHT cases by flipping them around to become
* JOIN_LEFT. This saves some code here and in some later planner routines,
* but the main reason to do it is to not need to invent a JOIN_REVERSE_ANTI
* join type.
*
* To ease recognition of strict qual clauses, we require this routine to be
* run after expression preprocessing (i.e., qual canonicalization and JOIN
* alias-var expansion).
*/
void reduce_outer_joins(PlannerInfo* root)
{
reduce_outer_joins_state* state = NULL;
* To avoid doing strictness checks on more quals than necessary, we want
* to stop descending the jointree as soon as there are no outer joins
* below our current point. This consideration forces a two-pass process.
* The first pass gathers information about which base rels appear below
* each side of each join clause, and about whether there are outer
* join(s) below each side of each join clause. The second pass examines
* qual clauses and changes join types as it descends the tree.
*/
state = reduce_outer_joins_pass1((Node*)root->parse->jointree);
if (state == NULL || !state->contains_outer)
ereport(ERROR,
(errmodule(MOD_OPT),
errcode(ERRCODE_OPTIMIZER_INCONSISTENT_STATE),
(errmsg("so where are the outer joins?"))));
reduce_outer_joins_pass2((Node*)root->parse->jointree, state, root, NULL, NIL, NIL);
}
* reduce_outer_joins_pass1 - phase 1 data collection
*
* Returns a state node describing the given jointree node.
*/
static reduce_outer_joins_state* reduce_outer_joins_pass1(Node* jtnode)
{
reduce_outer_joins_state* result = NULL;
result = (reduce_outer_joins_state*)palloc(sizeof(reduce_outer_joins_state));
result->relids = NULL;
result->contains_outer = false;
result->sub_states = NIL;
if (jtnode == NULL)
return result;
if (IsA(jtnode, RangeTblRef)) {
int varno = ((RangeTblRef*)jtnode)->rtindex;
result->relids = bms_make_singleton(varno);
} else if (IsA(jtnode, FromExpr)) {
FromExpr* f = (FromExpr*)jtnode;
ListCell* l = NULL;
foreach (l, f->fromlist) {
reduce_outer_joins_state* sub_state = NULL;
sub_state = reduce_outer_joins_pass1((Node*)lfirst(l));
result->relids = bms_add_members(result->relids, sub_state->relids);
result->contains_outer |= sub_state->contains_outer;
result->sub_states = lappend(result->sub_states, sub_state);
}
} else if (IsA(jtnode, JoinExpr)) {
JoinExpr* j = (JoinExpr*)jtnode;
reduce_outer_joins_state* sub_state = NULL;
if (IS_OUTER_JOIN(j->jointype))
result->contains_outer = true;
sub_state = reduce_outer_joins_pass1(j->larg);
result->relids = bms_add_members(result->relids, sub_state->relids);
result->contains_outer |= sub_state->contains_outer;
result->sub_states = lappend(result->sub_states, sub_state);
sub_state = reduce_outer_joins_pass1(j->rarg);
result->relids = bms_add_members(result->relids, sub_state->relids);
result->contains_outer |= sub_state->contains_outer;
result->sub_states = lappend(result->sub_states, sub_state);
} else {
ereport(ERROR,
(errmodule(MOD_OPT),
errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE),
errmsg("unrecognized node type: %d", (int)nodeTag(jtnode))));
}
return result;
}
* reduce_outer_joins_pass2 - phase 2 processing
*
* jtnode: current jointree node
* state: state data collected by phase 1 for this node
* root: toplevel planner state
* nonnullable_rels: set of base relids forced non-null by upper quals
* nonnullable_vars: list of Vars forced non-null by upper quals
* forced_null_vars: list of Vars forced null by upper quals
*/
static void reduce_outer_joins_pass2(Node* jtnode, reduce_outer_joins_state* state, PlannerInfo* root,
Relids nonnullable_rels, List* nonnullable_vars, List* forced_null_vars)
{
* pass 2 should never descend as far as an empty subnode or base rel,
* because it's only called on subtrees marked as contains_outer.
*/
if (jtnode == NULL)
ereport(
ERROR, (errmodule(MOD_OPT), errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED), (errmsg("reached empty jointree"))));
if (IsA(jtnode, RangeTblRef))
ereport(ERROR, (errmodule(MOD_OPT), errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE), (errmsg("reached base rel"))));
else if (IsA(jtnode, FromExpr)) {
FromExpr* f = (FromExpr*)jtnode;
ListCell* l = NULL;
ListCell* s = NULL;
Relids pass_nonnullable_rels;
List* pass_nonnullable_vars = NIL;
List* pass_forced_null_vars = NIL;
pass_nonnullable_rels = find_nonnullable_rels(f->quals);
pass_nonnullable_rels = bms_add_members(pass_nonnullable_rels, nonnullable_rels);
pass_nonnullable_vars = find_nonnullable_vars(f->quals);
pass_nonnullable_vars = list_concat(pass_nonnullable_vars, nonnullable_vars);
pass_forced_null_vars = find_forced_null_vars(f->quals);
pass_forced_null_vars = list_concat(pass_forced_null_vars, forced_null_vars);
AssertEreport(list_length(f->fromlist) == list_length(state->sub_states),
MOD_OPT_REWRITE,
"list length mismatch in reduce_outer_joins_pass2");
forboth(l, f->fromlist, s, state->sub_states)
{
reduce_outer_joins_state* sub_state = (reduce_outer_joins_state*)lfirst(s);
if (sub_state->contains_outer)
reduce_outer_joins_pass2((Node*)lfirst(l),
sub_state,
root,
pass_nonnullable_rels,
pass_nonnullable_vars,
pass_forced_null_vars);
}
bms_free_ext(pass_nonnullable_rels);
} else if (IsA(jtnode, JoinExpr)) {
JoinExpr* j = (JoinExpr*)jtnode;
int rtindex = j->rtindex;
JoinType jointype = j->jointype;
reduce_outer_joins_state* left_state = (reduce_outer_joins_state*)linitial(state->sub_states);
reduce_outer_joins_state* right_state = (reduce_outer_joins_state*)lsecond(state->sub_states);
List* local_nonnullable_vars = NIL;
bool computed_local_nonnullable_vars = false;
switch (jointype) {
case JOIN_INNER:
break;
case JOIN_LEFT:
if (bms_overlap(nonnullable_rels, right_state->relids))
jointype = JOIN_INNER;
break;
case JOIN_RIGHT:
if (bms_overlap(nonnullable_rels, left_state->relids))
jointype = JOIN_INNER;
break;
case JOIN_FULL:
if (bms_overlap(nonnullable_rels, left_state->relids)) {
if (bms_overlap(nonnullable_rels, right_state->relids))
jointype = JOIN_INNER;
else
jointype = JOIN_LEFT;
} else {
if (bms_overlap(nonnullable_rels, right_state->relids))
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.
*/
case JOIN_LEFT_ANTI_FULL:
case JOIN_RIGHT_ANTI_FULL:
* This should happened, since they are introduced by full join
* conversion, and before that, reduce outer has already be done
*/
break;
default: {
ereport(ERROR,
(errmodule(MOD_OPT),
errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE),
errmsg("unrecognized join type: %d", (int)jointype)));
} break;
}
* Convert JOIN_RIGHT to JOIN_LEFT. Note that in the case where we
* reduced JOIN_FULL to JOIN_RIGHT, this will mean the JoinExpr no
* longer matches the internal ordering of any CoalesceExpr's built to
* represent merged join variables. We don't care about that at
* present, but be wary of it ...
*/
if (jointype == JOIN_RIGHT || jointype == JOIN_RIGHT_ANTI_FULL) {
Node* tmparg = NULL;
tmparg = j->larg;
j->larg = j->rarg;
j->rarg = tmparg;
if (jointype == JOIN_RIGHT)
jointype = JOIN_LEFT;
else
jointype = JOIN_LEFT_ANTI_FULL;
right_state = (reduce_outer_joins_state*)linitial(state->sub_states);
left_state = (reduce_outer_joins_state*)lsecond(state->sub_states);
}
* See if we can reduce JOIN_LEFT to JOIN_ANTI. This is the case if
* the join's own quals are strict for any var that was forced null by
* higher qual levels. NOTE: there are other ways that we could
* detect an anti-join, in particular if we were to check whether Vars
* coming from the RHS must be non-null because of table constraints.
* That seems complicated and expensive though (in particular, one
* would have to be wary of lower outer joins). For the moment this
* seems sufficient.
*/
if (jointype == JOIN_LEFT) {
List* overlap = NIL;
local_nonnullable_vars = find_nonnullable_vars(j->quals);
computed_local_nonnullable_vars = true;
* It's not sufficient to check whether local_nonnullable_vars and
* forced_null_vars overlap: we need to know if the overlap
* includes any RHS variables.
*/
overlap = list_intersection(local_nonnullable_vars, forced_null_vars);
if (overlap != NIL && bms_overlap(pull_varnos((Node*)overlap), right_state->relids))
jointype = JOIN_ANTI;
}
if (rtindex && jointype != j->jointype) {
RangeTblEntry* rte = rt_fetch(rtindex, root->parse->rtable);
AssertEreport(rte->rtekind == RTE_JOIN,
MOD_OPT_REWRITE,
"RangeTblEntry should be kind of JOIN in reduce_outer_joins_pass2");
AssertEreport(
rte->jointype == j->jointype, MOD_OPT_REWRITE, "jointype mismatch in reduce_outer_joins_pass2");
rte->jointype = jointype;
}
j->jointype = jointype;
if (left_state->contains_outer || right_state->contains_outer) {
Relids local_nonnullable_rels;
List* local_forced_null_vars = NIL;
Relids pass_nonnullable_rels;
List* pass_nonnullable_vars = NIL;
List* pass_forced_null_vars = NIL;
* If this join is (now) inner, we can add any constraints its
* quals provide to those we got from above. But if it is outer,
* we can pass down the local constraints only into the nullable
* side, because an outer join never eliminates any rows from its
* non-nullable side. Also, there is no point in passing upper
* constraints into the nullable side, since if there were any
* we'd have been able to reduce the join. (In the case of upper
* forced-null constraints, we *must not* pass them into the
* nullable side --- they either applied here, or not.) The upshot
* is that we pass either the local or the upper constraints,
* never both, to the children of an outer join.
*
* Note that a SEMI join works like an inner join here: it's okay
* to pass down both local and upper constraints. (There can't be
* any upper constraints affecting its inner side, but it's not
* worth having a separate code path to avoid passing them.)
*
* At a FULL join we just punt and pass nothing down --- is it
* possible to be smarter?
*/
if (jointype != JOIN_FULL) {
local_nonnullable_rels = find_nonnullable_rels(j->quals);
if (!computed_local_nonnullable_vars)
local_nonnullable_vars = find_nonnullable_vars(j->quals);
local_forced_null_vars = find_forced_null_vars(j->quals);
if (jointype == JOIN_INNER || jointype == JOIN_SEMI) {
local_nonnullable_rels = bms_add_members(local_nonnullable_rels, nonnullable_rels);
local_nonnullable_vars = list_concat(local_nonnullable_vars, nonnullable_vars);
local_forced_null_vars = list_concat(local_forced_null_vars, forced_null_vars);
}
} else {
local_nonnullable_rels = NULL;
local_forced_null_vars = NIL;
}
if (left_state->contains_outer) {
if (jointype == JOIN_INNER || jointype == JOIN_SEMI) {
pass_nonnullable_rels = local_nonnullable_rels;
pass_nonnullable_vars = local_nonnullable_vars;
pass_forced_null_vars = local_forced_null_vars;
} else if (jointype != JOIN_FULL) {
pass_nonnullable_rels = nonnullable_rels;
pass_nonnullable_vars = nonnullable_vars;
pass_forced_null_vars = forced_null_vars;
} else {
pass_nonnullable_rels = NULL;
pass_nonnullable_vars = NIL;
pass_forced_null_vars = NIL;
}
reduce_outer_joins_pass2(
j->larg, left_state, root, pass_nonnullable_rels, pass_nonnullable_vars, pass_forced_null_vars);
}
if (right_state->contains_outer) {
if (jointype != JOIN_FULL) {
pass_nonnullable_rels = local_nonnullable_rels;
pass_nonnullable_vars = local_nonnullable_vars;
pass_forced_null_vars = local_forced_null_vars;
} else {
pass_nonnullable_rels = NULL;
pass_nonnullable_vars = NIL;
pass_forced_null_vars = NIL;
}
reduce_outer_joins_pass2(
j->rarg, right_state, root, pass_nonnullable_rels, pass_nonnullable_vars, pass_forced_null_vars);
}
bms_free_ext(local_nonnullable_rels);
}
} else {
ereport(ERROR,
(errmodule(MOD_OPT),
errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE),
errmsg("unrecognized node type: %d", (int)nodeTag(jtnode))));
}
}
* remove_useless_result_rtes
* Attempt to remove RTE_RESULT RTEs from the join tree.
*
* We can remove RTE_RESULT entries from the join tree using the knowledge
* that RTE_RESULT returns exactly one row and has no output columns. Hence,
* if one is inner-joined to anything else, we can delete it. Optimizations
* are also possible for some outer-join cases, as detailed below.
*
* Some of these optimizations depend on recognizing empty (constant-true)
* quals for FromExprs and JoinExprs. That makes it useful to apply this
* optimization pass after expression preprocessing, since that will have
* eliminated constant-true quals, allowing more cases to be recognized as
* optimizable. What's more, the usual reason for an RTE_RESULT to be present
* is that we pulled up a subquery or VALUES clause, thus very possibly
* replacing Vars with constants, making it more likely that a qual can be
* reduced to constant true. Also, because some optimizations depend on
* the outer-join type, it's best to have done reduce_outer_joins() first.
*
* A PlaceHolderVar referencing an RTE_RESULT RTE poses an obstacle to this
* process: we must remove the RTE_RESULT's relid from the PHV's phrels, but
* we must not reduce the phrels set to empty. If that would happen, and
* the RTE_RESULT is an immediate child of an outer join, we have to give up
* and not remove the RTE_RESULT: there is noplace else to evaluate the
* PlaceHolderVar. (That is, in such cases the RTE_RESULT *does* have output
* columns.) But if the RTE_RESULT is an immediate child of an inner join,
* we can change the PlaceHolderVar's phrels so as to evaluate it at the
* inner join instead. This is OK because we really only care that PHVs are
* evaluated above or below the correct outer joins.
*
* We used to try to do this work as part of pull_up_subqueries() where the
* potentially-optimizable cases get introduced; but it's way simpler, and
* more effective, to do it separately.
*/
void remove_useless_result_rtes(PlannerInfo *root)
{
ListCell *cell;
ListCell *prev;
ListCell *next;
Assert(IsA(root->parse->jointree, FromExpr));
root->parse->jointree = (FromExpr *)
remove_useless_results_recurse(root, (Node *) root->parse->jointree);
Assert(IsA(root->parse->jointree, FromExpr));
* Remove any PlanRowMark referencing an RTE_RESULT RTE. We obviously
* must do that for any RTE_RESULT that we just removed. But one for a
* RTE that we did not remove can be dropped anyway: since the RTE has
* only one possible output row, there is no need for EPQ to mark and
* restore that row.
*
* It's necessary, not optional, to remove the PlanRowMark for a surviving
* RTE_RESULT RTE; otherwise we'll generate a whole-row Var for the
* RTE_RESULT, which the executor has no support for.
*/
prev = NULL;
for (cell = list_head(root->rowMarks); cell; cell = next) {
PlanRowMark *rc = (PlanRowMark *) lfirst(cell);
next = lnext(cell);
if (rt_fetch(rc->rti, root->parse->rtable)->rtekind == RTE_RESULT)
root->rowMarks = list_delete_cell(root->rowMarks, cell, prev);
else
prev = cell;
}
}
* get_result_relid
* If jtnode is a RangeTblRef for an RTE_RESULT RTE, return its relid;
* otherwise return 0.
*/
int get_result_relid(PlannerInfo *root, Node *jtnode)
{
int varno;
if (!IsA(jtnode, RangeTblRef))
return 0;
varno = ((RangeTblRef *) jtnode)->rtindex;
if (rt_fetch(varno, root->parse->rtable)->rtekind != RTE_RESULT)
return 0;
return varno;
}
* remove_result_refs
* Helper routine for dropping an unneeded RTE_RESULT RTE.
*
* This doesn't physically remove the RTE from the jointree, because that's
* more easily handled in remove_useless_results_recurse. What it does do
* is the necessary cleanup in the rest of the tree: we must adjust any PHVs
* that may reference the RTE. Be sure to call this at a point where the
* jointree is valid (no disconnected nodes).
*
* Note that we don't need to process the append_rel_list, since RTEs
* referenced directly in the jointree won't be appendrel members.
*
* varno is the RTE_RESULT's relid.
* newjtloc is the jointree location at which any PHVs referencing the
* RTE_RESULT should be evaluated instead.
*/
void remove_result_refs(PlannerInfo *root, int varno, Node *newjtloc)
{
if (root->glob->lastPHId != 0) {
Relids subrelids;
subrelids = get_relids_in_jointree(newjtloc, false);
Assert(!bms_is_empty(subrelids));
substitute_multiple_relids((Node *) root->parse, varno, subrelids);
}
* We also need to remove any PlanRowMark referencing the RTE, but we
* postpone that work until we return to remove_useless_result_rtes.
*/
}
bool find_dependent_phvs_walker(Node *node,
find_dependent_phvs_context *context)
{
if (node == NULL)
return false;
if (IsA(node, PlaceHolderVar)) {
PlaceHolderVar *phv = (PlaceHolderVar *) node;
if ((int)(phv->phlevelsup) == context->sublevels_up &&
bms_equal(context->relids, phv->phrels))
return true;
}
if (IsA(node, Query)) {
bool result;
context->sublevels_up++;
result = query_tree_walker((Query *) node, (bool (*)())find_dependent_phvs_walker,
(void *) context, 0);
context->sublevels_up--;
return result;
}
Assert(!IsA(node, SpecialJoinInfo));
Assert(!IsA(node, AppendRelInfo));
Assert(!IsA(node, PlaceHolderInfo));
Assert(!IsA(node, MinMaxAggInfo));
return expression_tree_walker(node, (bool (*)())find_dependent_phvs_walker,
(void *) context);
}
bool find_dependent_phvs(Node *node, int varno)
{
find_dependent_phvs_context context;
context.relids = bms_make_singleton(varno);
context.sublevels_up = 0;
* Must be prepared to start with a Query or a bare expression tree.
*/
return query_or_expression_tree_walker(node, (bool (*)())find_dependent_phvs_walker,
(void *) &context,
0);
}
* substitute_multiple_relids - adjust node relid sets after pulling up
* a subquery
*
* Find any PlaceHolderVar nodes in the given tree that reference the
* pulled-up relid, and change them to reference the replacement relid(s).
*
* 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
* pullup_replace_vars earlier. Avoid scribbling on the original values of
* the bitmapsets, though, because expression_tree_mutator doesn't copy those.
*/
typedef struct {
int varno;
int sublevels_up;
Relids subrelids;
} substitute_multiple_relids_context;
static bool substitute_multiple_relids_walker(Node* node, substitute_multiple_relids_context* context)
{
if (node == NULL)
return false;
if (IsA(node, PlaceHolderVar)) {
PlaceHolderVar* phv = (PlaceHolderVar*)node;
if ((int)phv->phlevelsup == context->sublevels_up && bms_is_member(context->varno, phv->phrels)) {
phv->phrels = bms_union(phv->phrels, context->subrelids);
phv->phrels = bms_del_member(phv->phrels, context->varno);
}
}
if (IsA(node, Query)) {
bool result = false;
context->sublevels_up++;
result = query_tree_walker((Query*)node, (bool (*)())substitute_multiple_relids_walker, (void*)context, 0);
context->sublevels_up--;
return result;
}
AssertEreport(!IsA(node, SpecialJoinInfo),
MOD_OPT_REWRITE,
"Shouldn't need to handle planner auxiliary node SpecialJoinInfo in substitute_multiple_relids_walker");
Assert(!IsA(node, LateralJoinInfo));
AssertEreport(!IsA(node, AppendRelInfo),
MOD_OPT_REWRITE,
"Shouldn't need to handle planner auxiliary node AppendRelInfo in substitute_multiple_relids_walker");
AssertEreport(!IsA(node, PlaceHolderInfo),
MOD_OPT_REWRITE,
"Shouldn't need to handle planner auxiliary node PlaceHolderInfo in substitute_multiple_relids_walker");
AssertEreport(!IsA(node, MinMaxAggInfo),
MOD_OPT_REWRITE,
"Shouldn't need to handle planner auxiliary node MinMaxAggInfo in substitute_multiple_relids_walker");
return expression_tree_walker(node, (bool (*)())substitute_multiple_relids_walker, (void*)context);
}
static void substitute_multiple_relids(Node* node, int varno, Relids subrelids)
{
substitute_multiple_relids_context context;
context.varno = varno;
context.sublevels_up = 0;
context.subrelids = subrelids;
* Must be prepared to start with a Query or a bare expression tree.
*/
(void)query_or_expression_tree_walker(node, (bool (*)())substitute_multiple_relids_walker, (void*)&context, 0);
}
* fix_append_rel_relids: update RT-index fields of AppendRelInfo nodes
*
* When we pull up a subquery, any AppendRelInfo references to the subquery's
* RT index have to be replaced by the substituted relid (and there had better
* be only one). We also need to apply substitute_multiple_relids to their
* translated_vars lists, since those might contain PlaceHolderVars.
*
* We assume we may modify the AppendRelInfo nodes in-place.
*/
static void fix_append_rel_relids(List* append_rel_list, int varno, Relids subrelids)
{
ListCell* l = NULL;
int subvarno = -1;
* We only want to extract the member relid once, but we mustn't fail
* immediately if there are multiple members; it could be that none of the
* AppendRelInfo nodes refer to it. So compute it on first use. Note that
* bms_singleton_member will complain if set is not singleton.
*/
foreach (l, append_rel_list) {
AppendRelInfo* appinfo = (AppendRelInfo*)lfirst(l);
AssertEreport(appinfo->parent_relid != (uint)varno,
MOD_OPT_REWRITE,
"The parent_relid shouldn't ever be a pullup target in fix_append_rel_relids");
if (appinfo->child_relid == (uint)varno) {
if (subvarno < 0)
subvarno = bms_singleton_member(subrelids);
appinfo->child_relid = subvarno;
}
substitute_multiple_relids((Node*)appinfo->translated_vars, varno, subrelids);
}
}
* get_relids_in_jointree: get set of RT indexes present in a jointree
*
* If include_joins is true, join RT indexes are included; if false,
* only base rels are included.
*/
Relids get_relids_in_jointree(Node* jtnode, bool include_joins)
{
Relids result = NULL;
if (jtnode == NULL)
return result;
if (IsA(jtnode, RangeTblRef)) {
int varno = ((RangeTblRef*)jtnode)->rtindex;
result = bms_make_singleton(varno);
} else if (IsA(jtnode, FromExpr)) {
FromExpr* f = (FromExpr*)jtnode;
ListCell* l = NULL;
foreach (l, f->fromlist) {
result = bms_join(result, get_relids_in_jointree((Node*)lfirst(l), include_joins));
}
} else if (IsA(jtnode, JoinExpr)) {
JoinExpr* j = (JoinExpr*)jtnode;
result = get_relids_in_jointree(j->larg, include_joins);
result = bms_join(result, get_relids_in_jointree(j->rarg, include_joins));
if (include_joins && j->rtindex)
result = bms_add_member(result, j->rtindex);
} else {
ereport(ERROR,
(errmodule(MOD_OPT),
errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE),
errmsg("unrecognized node type: %d", (int)nodeTag(jtnode))));
}
return result;
}
* get_relids_for_join: get set of base RT indexes making up a join
*/
Relids get_relids_for_join(PlannerInfo* root, int joinrelid)
{
Node* jtnode = NULL;
jtnode = find_jointree_node_for_rel((Node*)root->parse->jointree, joinrelid);
if (jtnode == NULL)
ereport(ERROR,
(errmodule(MOD_OPT),
errcode(ERRCODE_NULL_VALUE_NOT_ALLOWED),
(errmsg("could not find join node %d", joinrelid))));
return get_relids_in_jointree(jtnode, false);
}
* find_jointree_node_for_rel: locate jointree node for a base or join RT index
*
* Returns NULL if not found
*/
static Node* find_jointree_node_for_rel(Node* jtnode, int relid)
{
if (jtnode == NULL)
return NULL;
if (IsA(jtnode, RangeTblRef)) {
int varno = ((RangeTblRef*)jtnode)->rtindex;
if (relid == varno)
return jtnode;
} else if (IsA(jtnode, FromExpr)) {
FromExpr* f = (FromExpr*)jtnode;
ListCell* l = NULL;
foreach (l, f->fromlist) {
jtnode = find_jointree_node_for_rel((Node*)lfirst(l), relid);
if (jtnode != NULL)
return jtnode;
}
} else if (IsA(jtnode, JoinExpr)) {
JoinExpr* j = (JoinExpr*)jtnode;
if (relid == j->rtindex)
return jtnode;
jtnode = find_jointree_node_for_rel(j->larg, relid);
if (jtnode != NULL)
return jtnode;
jtnode = find_jointree_node_for_rel(j->rarg, relid);
if (jtnode != NULL)
return jtnode;
} else {
ereport(ERROR,
(errmodule(MOD_OPT),
errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE),
errmsg("unrecognized node type: %d", (int)nodeTag(jtnode))));
}
return NULL;
}
* We use this function to determine whether we should rewrite a 'full join on P' query to
* a 'left join on P union all right anti full join on P'.
* If we can find a condition to redistribute two relations, we will not rewrite, otherwise, we will.
*/
bool equalAndRedistributable(Node* quals)
{
bool ret = false;
if (quals == NULL)
return false;
switch (nodeTag(quals)) {
case T_OpExpr: {
OpExpr* op = (OpExpr*)quals;
if (list_length(op->args) != 2)
break;
if (op->opno >= FirstNormalObjectId)
break;
char* opname = get_opname(op->opno);
if (opname == NULL)
break;
* no need to rewrite.
*/
if (strcmp(opname, "=") == 0) {
ret = true;
ListCell* lc = NULL;
foreach (lc, op->args) {
Node* node = (Node*)lfirst(lc);
if (!IsTypeDistributable(exprType(node))) {
ret = false;
break;
}
}
}
pfree_ext(opname);
break;
}
case T_List: {
ListCell* lc = NULL;
* If it is a List, all ListCells must be AND-ed, if we find a
* qual that is '=' and redistributable, then return true;
*/
foreach (lc, (List*)quals) {
bool tmp = equalAndRedistributable((Node*)lfirst(lc));
if (tmp) {
ret = true;
break;
}
}
break;
}
case T_BoolExpr: {
BoolExpr* op = (BoolExpr*)quals;
ListCell* lc = NULL;
* If it is a List, all ListCells must be AND-ed, if we find a
* qual that is '=' and redistributable, then return true;
* All other cases must rewrite.
*/
if (op->boolop == AND_EXPR) {
foreach (lc, op->args) {
bool tmp = equalAndRedistributable((Node*)lfirst(lc));
if (tmp) {
ret = true;
break;
}
}
}
break;
}
default:
ret = false;
break;
}
return ret;
}
* After rewritting a 'full join on 1=1' to a 'left join union all right anti full join' query,
* some operations can not be done on subqueries, so we reset them to NULL.
* These operations will be done on the parent query.
*/
static void reset_operations_need_done_on_parent(Query* query)
{
AssertEreport(IsA(query, Query), MOD_OPT_REWRITE, "query mismatch in reset_operations_need_done_on_parent");
query->hasAggs = false;
query->groupClause = NIL;
query->groupingSets = NIL;
query->sortClause = NIL;
query->distinctClause = NIL;
query->hasDistinctOn = NIL;
query->limitCount = NULL;
query->limitOffset = NULL;
query->hasWindowFuncs = false;
query->windowClause = NULL;
query->havingQual = NULL;
query->mergeTarget_relation = 0;
query->mergeSourceTargetList = NIL;
query->mergeActionList = NIL;
}
* reduce_inequality_fulljoins
* Entry function to implement 'full join on 1=1' rewriting. We will call
* reduce_inequality_fulljoins_jointree_recurse recursively to implement it.
*/
void reduce_inequality_fulljoins(PlannerInfo* root)
{
Node* jtnode = NULL;
jtnode = reduce_inequality_fulljoins_jointree_recurse(root, (Node*)root->parse->jointree);
* 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);
}
* reduce_inequality_fulljoins_jointree_recurse
*
* Rewrite a 'full join' to 'left join union all right anti full join'.
*
* Consider this query: select * from t1 full join t2 on 1=1
*
* In stand-alone system, all data of t1 and t2 are on a same node, we can use
* merge join to process this query. But, in a distribute system, data of t1 and
* t2 are redistributed on multiple servers, we can not use merge join directly.
* If we move all data of t1 and t2 to the same node, this node maybe can not
* hold it, especially on a cluster which processes large amount of data.
*
* This function will rewrite this query to (select *from t1 left join t2 on 1=1)
* union all (select *from t1 right anti full join t2 on 1=1) NOTE: This query
* is a user-friendly expression of the internal query tree,and users can not
* send this query to GaussDB directly.
*
* We can only user Nestloop join method to execute this query, because there is
* no join key.
*
* If a query like this: select * from t1 full join t2 on P, and no expressions
* on P is distributable, we will rewrite the query also. For example, t1.floata
* = t2.floata, floata's type is float, which is not redistributable. In this
* example, we can use nestloop, hashjoin or mergejoin after rewritting and
* broadcast one of the two tables.
*
* If we find a JoinExpr which meets the rewritting condition, we begin to rewrite.
* We copy the original query twice, one of them expresses left join and the other
* one expresses right anti full join. We use another query which called
* partial_query to express union query.
*
* Some operations, such as limit, agg, etc., can not be execute on the two
* subqueries copied from the original query, so we should reset this operation
* nodes to empty.
*
* If multiple JoinExpr on the same layer(in the same fromlist), we process them
* one by one in one recursive invocation.
*
* If multiple JoinExpr on different layers, we only process the top layer in
* one recursive invocation, lower layers will be processesed in deeper recursive
* invocations.
*/
static Node* reduce_inequality_fulljoins_jointree_recurse(PlannerInfo* root, Node* jtnode)
{
#ifdef ENABLE_MULTIPLE_NODES
Assert(IS_STREAM_PLAN);
#endif
if (jtnode == NULL || IsA(jtnode, RangeTblRef)) {
return jtnode;
} else if (IsA(jtnode, FromExpr)) {
FromExpr* f = (FromExpr*)jtnode;
List* newfromlist = NIL;
ListCell* l = NULL;
foreach (l, f->fromlist) {
Node* newchild = NULL;
newchild = reduce_inequality_fulljoins_jointree_recurse(root, (Node*)lfirst(l));
newfromlist = lappend(newfromlist, newchild);
}
jtnode = (Node*)makeFromExpr(newfromlist, (Node*)copyObject(f->quals));
} else if (IsA(jtnode, JoinExpr)) {
JoinExpr* j = (JoinExpr*)jtnode;
if (j->jointype == JOIN_FULL && !equalAndRedistributable(j->quals) && root->parse->commandType != CMD_MERGE) {
Query* partial_query = makeNode(Query);
Query* setop1 = (Query*)copyObject(root->parse);
Query* setop2 = (Query*)copyObject(root->parse);
setop1->is_from_full_join_rewrite = true;
setop2->is_from_full_join_rewrite = true;
JoinExpr* j1 = (JoinExpr*)copyObject(j);
JoinExpr* j2 = (JoinExpr*)copyObject(j);
RangeTblEntry* joinrte = (RangeTblEntry*)list_nth(root->parse->rtable, j->rtindex - 1);
RangeTblEntry* joinrte1 = (RangeTblEntry*)list_nth(setop1->rtable, j->rtindex - 1);
RangeTblEntry* joinrte2 = (RangeTblEntry*)list_nth(setop2->rtable, j->rtindex - 1);
j1->jointype = JOIN_LEFT;
j2->jointype = JOIN_RIGHT_ANTI_FULL;
joinrte1->jointype = JOIN_LEFT;
joinrte2->jointype = JOIN_RIGHT_ANTI_FULL;
* vars' levelsup in qulas.
*/
IncrementVarSublevelsUp(j1->quals, 2, 1);
IncrementVarSublevelsUp(j2->quals, 2, 1);
* Upper-level vars in subquery are now two level far to their parent
* than before.
*/
IncrementVarSublevelsUp((Node*)setop1, 2, 1);
IncrementVarSublevelsUp((Node*)setop2, 2, 1);
* source code file.
*/
setop1->jointree = makeFromExpr(list_make1(j1), NULL);
setop2->jointree = makeFromExpr(list_make1(j2), NULL);
setop1->commandType = CMD_SELECT;
setop2->commandType = CMD_SELECT;
setop1->resultRelation = 0;
setop2->resultRelation = 0;
int resno = 1;
ListCell* lc = NULL;
List* targetList = NIL;
List* colnames = joinrte->eref->colnames;
* Make targetlist for two subqueries.
* All vars in joinaliasvars should be added to the subquery's targetlist.
*/
foreach (lc, joinrte->joinaliasvars) {
TargetEntry* te = NULL;
Expr* expr = NULL;
Node* node = (Node*)lfirst(lc);
char* varname = strVal(list_nth(colnames, resno - 1));
switch (nodeTag(node)) {
case T_Var:
expr =
(Expr*)makeVar(j->rtindex, resno, exprType(node), exprTypmod(node), exprCollation(node), 0);
break;
default:
expr = (Expr*)copyObject(node);
break;
}
te = makeTargetEntry((Expr*)expr, resno, varname, false);
targetList = lappend(targetList, te);
resno++;
}
setop1->targetList = targetList;
setop2->targetList = targetList;
* Reset some members to NULL, such as members related to agg, limit,
* window function. We will do these operations in the parent query,
* not in subqueries, so reset them to NULL.
*/
reset_operations_need_done_on_parent(setop1);
reset_operations_need_done_on_parent(setop2);
RangeTblEntry* rte1 = addRangeTableEntryForSubquery(NULL, setop1, makeAlias("setop1", NIL), false, true);
RangeTblEntry* rte2 = addRangeTableEntryForSubquery(NULL, setop2, makeAlias("setop2", NIL), false, true);
partial_query->commandType = CMD_SELECT;
partial_query->canSetTag = true;
partial_query->rtable = list_make2(rte1, rte2);
partial_query->jointree = makeFromExpr(NIL, NULL);
partial_query->can_push = root->parse->can_push;
SetOperationStmt* op = makeNode(SetOperationStmt);
op->op = SETOP_UNION;
op->all = true;
RangeTblRef* rtr1 = makeNode(RangeTblRef);
RangeTblRef* rtr2 = makeNode(RangeTblRef);
rtr1->rtindex = 1;
rtr2->rtindex = 2;
op->larg = (Node*)rtr1;
op->rarg = (Node*)rtr2;
partial_query->setOperations = (Node*)op;
int newVarNo = list_length(root->parse->rtable) + 1;
List* old_tlist = NIL;
List* new_tlist = NIL;
AttrNumber iterator_attno = 1;
* 2. Create old_tlist and new_tlist which mapped old vars to new vars.
* We will use these two lists to replace old vars in the parent query to new vars.
*/
foreach (lc, joinrte->joinaliasvars) {
Node* node = (Node*)lfirst(lc);
char* varname = strVal(list_nth(colnames, iterator_attno - 1));
Var* pvar = makeVar(1, iterator_attno, exprType(node), exprTypmod(node), exprCollation(node), 0);
TargetEntry* te = makeTargetEntry((Expr*)pvar,
list_length(partial_query->targetList) + 1,
varname,
false);
partial_query->targetList = lappend(partial_query->targetList, te);
Node* oldvar = NULL;
Node* newvar = NULL;
switch (node->type) {
case T_Var: {
Var* var = (Var*)node;
Index varno = var->varno;
AttrNumber varattno = var->varattno;
Node* retnode = get_real_rte_varno_attno_or_node(root->parse, &varno, &varattno);
if (retnode == NULL) {
oldvar = (Node*)makeVar(
varno, varattno, exprType(node), exprTypmod(node), exprCollation(node), 0);
} else {
oldvar = (Node*)copyObject(retnode);
oldvar = eval_const_expressions(root, oldvar);
}
} break;
default:
oldvar = (Node*)copyObject(node);
oldvar = eval_const_expressions(root, oldvar);
break;
}
newvar =
(Node*)makeVar(newVarNo, iterator_attno, exprType(node), exprTypmod(node), exprCollation(node), 0);
old_tlist = lappend(old_tlist, oldvar);
new_tlist = lappend(new_tlist, newvar);
op->colTypes = lappend_oid(op->colTypes, exprType(node));
op->colTypmods = lappend_int(op->colTypmods, exprTypmod(node));
op->colCollations = lappend_oid(op->colCollations, exprCollation(node));
iterator_attno++;
}
RangeTblEntry* rte = addRangeTableEntryForSubquery(NULL, partial_query, makeAlias("subquery", NIL), false, true);
rte->pulled_from_subquery = true;
root->parse->rtable = lappend(root->parse->rtable, rte);
root->parse->targetList = (List*)replace_node_clause(
(Node*)root->parse->targetList, (Node*)old_tlist, (Node*)new_tlist, RNC_RECURSE_AGGREF);
root->parse->jointree = (FromExpr*)replace_node_clause(
(Node*)root->parse->jointree, (Node*)old_tlist, (Node*)new_tlist, RNC_RECURSE_AGGREF);
root->parse->havingQual = (Node*)replace_node_clause(
(Node*)root->parse->havingQual, (Node*)old_tlist, (Node*)new_tlist, RNC_RECURSE_AGGREF);
root->parse->mergeSourceTargetList = (List*)replace_node_clause(
(Node*)root->parse->mergeSourceTargetList, (Node*)old_tlist, (Node*)new_tlist, RNC_RECURSE_AGGREF);
root->parse->mergeActionList = (List*)replace_node_clause(
(Node*)root->parse->mergeActionList, (Node*)old_tlist, (Node*)new_tlist, RNC_RECURSE_AGGREF);
RangeTblRef* rtr = makeNode(RangeTblRef);
rtr->rtindex = newVarNo;
jtnode = (Node*)rtr;
} else {
j->larg = reduce_inequality_fulljoins_jointree_recurse(root, j->larg);
j->rarg = reduce_inequality_fulljoins_jointree_recurse(root, j->rarg);
}
} else
ereport(ERROR,
((errmodule(MOD_OPT),
errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("unrecognized node type: %d", (int)nodeTag(jtnode)))));
return jtnode;
}
extern bool find_rownum_in_quals(PlannerInfo *root)
{
if (root->parse == NULL) {
return false;
}
if(root->hasRownumQual || root->hasRownumCheck) {
return root->hasRownumQual;
}
bool hasRownum = false;
ListCell *qualcell = NULL;
List *quallist = get_quals_lists((Node *)root->parse->jointree);
foreach (qualcell, quallist) {
Node *clause = (Node *)lfirst(qualcell);
if (contain_rownum_walker(clause, NULL)) {
hasRownum = true;
break;
}
}
root->hasRownumCheck = true;
return hasRownum;
}
bool ContainRownumQual(const Query *parse)
{
if (!IsA(parse->jointree, FromExpr)) {
return false;
}
return contain_rownum_walker(((FromExpr *)parse->jointree)->quals, NULL);
}
* @brief pull_up_sublinks_having
* Pull up sublinks from HAVING quals.
*
* For sublinks in HAVING clause, make the sublink a subquery(outer query) and join with the
* original query(inner query). What is left for that specific qual with sublink is
* transoformed into a operation between the result from the inner query and the outer query.
*
* For example: (Original Query)
* SELECT a, SUM(b) AS value FROM t1
* GROUP BY a HAVING SUM(a) >= (SELECT AVG(b) FROM t1)
* ORDER BY value DESC;
* Will turn into: (Rewritten Query)
* SELECT __inner_query__.a,
* __inner_query__.value
* FROM
* (SELECT a, SUM(b) AS value, SUM(a) AS sum_a FROM t1 GROUP BY a) AS __inner_query__,
* (SELECT avg(b) AS avg_b FROM t1) AS __outer_query__
* WHERE __inner_query__.sum_a >= __outer_query__.avg_b
* ORDER BY value DESC;
*
* There are some limitations for this:
* (1) Correlated sublink is not handled.
* (2) Sublink must work as a expression(An aggregation sublink rather than LIMIT).
* (3) Only pullup once.
*
* @param root Planner info
* @return Node* Rewritten Query
*/
static void pull_up_sublinks_having(PlannerInfo* root)
{
Query* inner_query = NULL;
List* old_expr_list = NIL;
List* new_expr_list = NIL;
List* old_var_list = NIL;
List* new_var_list = NIL;
ListCell* lc = NULL;
Assert(root->parse->havingQual != NULL);
* Step 1: Make the original query an subquery(inner_query).
* Notice that the root->parse has been updated in push_down_one_query.
* Therefore, after push_down_one_query is invoked, root->parse
* is no longer the inner query but the SELECT wrapper.
*/
push_down_one_query(root, &inner_query);
* Step 2: Pull up HAVING clause, turn it into a qual.
* 1. move all sortgroup clause in HAVING to targetist
* 2. add missing vars in HAVING to targetlist(basically unjunk the target entry)
* 3. pull up HAVING as quals, then replace vars with added vars in (2)
*/
old_expr_list = pull_aggref(inner_query->havingQual);
foreach(lc, old_expr_list) {
Aggref* agg = lfirst_node(Aggref, lc);
RangeTblEntry* rte = linitial_node(RangeTblEntry, root->parse->rtable);
TargetEntry* tle = NULL;
Var* new_var = NULL;
tle = makeTargetEntry((Expr*)agg,
list_length(inner_query->targetList) + 1,
"?column?",
false);
inner_query->targetList = lappend(inner_query->targetList, tle);
new_var = makeVarFromTargetEntry((Index)1, tle);
new_expr_list = lappend(new_expr_list, new_var);
if (rte->eref != NULL) {
rte->eref->colnames = lappend(rte->eref->colnames, makeString(tle->resname));
}
}
inner_query->havingQual = replace_node_clause((Node*)inner_query->havingQual,
(Node*)old_expr_list,
(Node*)new_expr_list,
RNC_REPLACE_FIRST_ONLY);
foreach(lc, inner_query->targetList) {
TargetEntry* tle = lfirst_node(TargetEntry, lc);
List* varlist = NIL;
Var* new_var = NULL;
Var* old_var = NULL;
if (!tle->resjunk || tle->ressortgroupref == 0) {
continue;
}
tle->resjunk = false;
new_var = makeVarFromTargetEntry((Index)1, tle);
new_var_list = lappend(new_var_list, new_var);
varlist = pull_var_clause((Node*)(tle->expr),
PVC_REJECT_AGGREGATES,
PVC_REJECT_PLACEHOLDERS);
AssertEreport(list_length(varlist) == 1, MOD_OPT_REWRITE,
"Cannot pull up HAVING from inner query, because inner query is broken.");
old_var = linitial_node(Var, varlist);
old_var_list = lappend(old_var_list, old_var);
}
root->parse->jointree->quals = \
replace_node_clause((Node*)inner_query->havingQual,
(Node*)old_var_list,
(Node*)new_var_list,
RNC_NONE);
inner_query->havingQual = NULL;
list_free_ext(old_expr_list);
list_free_ext(new_expr_list);
list_free_ext(old_var_list);
list_free_ext(new_var_list);
* Step 3: Pull up sort and limit clauses.
*/
pull_up_sort_limit_clause(root->parse, inner_query, true);
* Final Step: Invoke generic sublink pullup out(pull up outer_query).
* This method is invoked before generic sublink pullups.
* The final step is proceed in pull_up_sublinks.
*/
}
* @brief is_safe_pull_up_having
* Check if is safe for pull having clause.
*/
static bool is_safe_pull_up_sublink_having(PlannerInfo* root)
{
ListCell *lc = NULL;
List *sublinkList = NULL;
OpExpr* expr = NULL;
SubLink *sublink = NULL;
Relids level_up_varnos = NULL;
Query* subQuery = NULL;
Node* node = NULL;
List* aggreflist = NIL;
if (root->parse->groupClause == NULL || root->parse->havingQual == NULL) {
return false;
}
if (!IsA(root->parse->havingQual, OpExpr)) {
return false;
}
expr = (OpExpr*)(root->parse->havingQual);
if (!safe_pullup_op_expr_sublink(expr)) {
return false;
}
foreach(lc, expr->args)
{
node = (Node*)lfirst(lc);
if (IsA(node, SubLink)) {
continue;
}
aggreflist = pull_aggref(node);
if (list_length(aggreflist) == 0) {
return false;
}
list_free(aggreflist);
}
sublinkList = pull_sublink((Node*)root->parse->havingQual, 0, false, false);
foreach(lc, sublinkList)
{
sublink = (SubLink *)lfirst(lc);
subQuery = castNode(Query, sublink->subselect);
level_up_varnos = pull_varnos((Node*)subQuery->jointree, 1, true);
if (!bms_is_empty(level_up_varnos)) {
bms_free(level_up_varnos);
list_free_ext(sublinkList);
return false;
}
}
bms_free(level_up_varnos);
list_free_ext(sublinkList);
return true;
}
