529 lines
14 KiB
C
529 lines
14 KiB
C
/*-------------------------------------------------------------------------
|
|
*
|
|
* joinrels.c--
|
|
* Routines to determine which relations should be joined
|
|
*
|
|
* Copyright (c) 1994, Regents of the University of California
|
|
*
|
|
*
|
|
* IDENTIFICATION
|
|
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/joinrels.c,v 1.1.1.1 1996/07/09 06:21:36 scrappy Exp $
|
|
*
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
#include "postgres.h"
|
|
|
|
#include "nodes/pg_list.h"
|
|
#include "nodes/relation.h"
|
|
|
|
#include "optimizer/internal.h"
|
|
#include "optimizer/cost.h"
|
|
#include "optimizer/paths.h"
|
|
#include "optimizer/tlist.h"
|
|
#include "optimizer/joininfo.h"
|
|
#include "optimizer/pathnode.h"
|
|
|
|
|
|
static List *find_clause_joins(Query *root, Rel *outer_rel, List *joininfo_list);
|
|
static List *find_clauseless_joins(Rel *outer_rel, List *inner_rels);
|
|
static Rel *init_join_rel(Rel *outer_rel, Rel *inner_rel, JInfo *joininfo);
|
|
static List *new_join_tlist(List *tlist, List *other_relids,
|
|
int first_resdomno);
|
|
static List *new_joininfo_list(List *joininfo_list, List *join_relids);
|
|
static void add_superrels(Rel *rel, Rel *super_rel);
|
|
static bool nonoverlap_rels(Rel *rel1, Rel *rel2);
|
|
static bool nonoverlap_sets(List *s1, List *s2);
|
|
static void set_joinrel_size(Rel *joinrel, Rel *outer_rel, Rel *inner_rel,
|
|
JInfo *jinfo);
|
|
|
|
/*
|
|
* find-join-rels--
|
|
* Find all possible joins for each of the outer join relations in
|
|
* 'outer-rels'. A rel node is created for each possible join relation,
|
|
* and the resulting list of nodes is returned. If at all possible, only
|
|
* those relations for which join clauses exist are considered. If none
|
|
* of these exist for a given relation, all remaining possibilities are
|
|
* considered.
|
|
*
|
|
* 'outer-rels' is the list of rel nodes
|
|
*
|
|
* Returns a list of rel nodes corresponding to the new join relations.
|
|
*/
|
|
List *
|
|
find_join_rels(Query *root, List *outer_rels)
|
|
{
|
|
List *joins = NIL;
|
|
List *join_list = NIL;
|
|
List *r = NIL;
|
|
|
|
foreach(r, outer_rels) {
|
|
Rel *outer_rel = (Rel *)lfirst(r);
|
|
|
|
if(!(joins = find_clause_joins(root, outer_rel,outer_rel->joininfo)))
|
|
if (BushyPlanFlag)
|
|
joins = find_clauseless_joins(outer_rel,outer_rels);
|
|
else
|
|
joins = find_clauseless_joins(outer_rel,root->base_relation_list_);
|
|
|
|
join_list = nconc(join_list, joins);
|
|
}
|
|
|
|
return(join_list);
|
|
}
|
|
|
|
/*
|
|
* find-clause-joins--
|
|
* Determines whether joins can be performed between an outer relation
|
|
* 'outer-rel' and those relations within 'outer-rel's joininfo nodes
|
|
* (i.e., relations that participate in join clauses that 'outer-rel'
|
|
* participates in). This is possible if all but one of the relations
|
|
* contained within the join clauses of the joininfo node are already
|
|
* contained within 'outer-rel'.
|
|
*
|
|
* 'outer-rel' is the relation entry for the outer relation
|
|
* 'joininfo-list' is a list of join clauses which 'outer-rel'
|
|
* participates in
|
|
*
|
|
* Returns a list of new join relations.
|
|
*/
|
|
static List *
|
|
find_clause_joins(Query *root, Rel *outer_rel, List *joininfo_list)
|
|
{
|
|
List *join_list = NIL;
|
|
List *i = NIL;
|
|
|
|
foreach (i, joininfo_list) {
|
|
JInfo *joininfo = (JInfo*)lfirst(i);
|
|
Rel *rel;
|
|
|
|
if(!joininfo->inactive) {
|
|
List *other_rels = joininfo->otherrels;
|
|
|
|
if(other_rels != NIL) {
|
|
if(length(other_rels) == 1) {
|
|
rel = init_join_rel(outer_rel,
|
|
get_base_rel(root, lfirsti(other_rels)),
|
|
joininfo);
|
|
} else if (BushyPlanFlag) {
|
|
rel = init_join_rel(outer_rel,
|
|
get_join_rel(root, other_rels),
|
|
joininfo);
|
|
} else {
|
|
rel = NULL;
|
|
}
|
|
|
|
if (rel != NULL)
|
|
join_list = lappend(join_list, rel);
|
|
}
|
|
}
|
|
}
|
|
|
|
return(join_list);
|
|
}
|
|
|
|
/*
|
|
* find-clauseless-joins--
|
|
* Given an outer relation 'outer-rel' and a list of inner relations
|
|
* 'inner-rels', create a join relation between 'outer-rel' and each
|
|
* member of 'inner-rels' that isn't already included in 'outer-rel'.
|
|
*
|
|
* Returns a list of new join relations.
|
|
*/
|
|
static List *
|
|
find_clauseless_joins(Rel *outer_rel, List *inner_rels)
|
|
{
|
|
Rel *inner_rel;
|
|
List *t_list = NIL;
|
|
List *temp_node = NIL;
|
|
List *i = NIL;
|
|
|
|
foreach (i, inner_rels) {
|
|
inner_rel = (Rel *)lfirst(i);
|
|
if(nonoverlap_rels(inner_rel, outer_rel)) {
|
|
temp_node = lcons(init_join_rel(outer_rel,
|
|
inner_rel,
|
|
(JInfo*)NULL),
|
|
NIL);
|
|
t_list = nconc(t_list,temp_node);
|
|
}
|
|
}
|
|
|
|
return(t_list);
|
|
}
|
|
|
|
/*
|
|
* init-join-rel--
|
|
* Creates and initializes a new join relation.
|
|
*
|
|
* 'outer-rel' and 'inner-rel' are relation nodes for the relations to be
|
|
* joined
|
|
* 'joininfo' is the joininfo node(join clause) containing both
|
|
* 'outer-rel' and 'inner-rel', if any exists
|
|
*
|
|
* Returns the new join relation node.
|
|
*/
|
|
static Rel *
|
|
init_join_rel(Rel *outer_rel, Rel *inner_rel, JInfo *joininfo)
|
|
{
|
|
Rel *joinrel = makeNode(Rel);
|
|
List *joinrel_joininfo_list = NIL;
|
|
List *new_outer_tlist;
|
|
List *new_inner_tlist;
|
|
|
|
/*
|
|
* Create a new tlist by removing irrelevant elements from both
|
|
* tlists of the outer and inner join relations and then merging
|
|
* the results together.
|
|
*/
|
|
new_outer_tlist =
|
|
new_join_tlist(outer_rel->targetlist, /* XXX 1-based attnos */
|
|
inner_rel->relids, 1);
|
|
new_inner_tlist =
|
|
new_join_tlist(inner_rel->targetlist, /* XXX 1-based attnos */
|
|
outer_rel->relids,
|
|
length(new_outer_tlist) + 1);
|
|
|
|
joinrel->relids = NIL;
|
|
joinrel->indexed = false;
|
|
joinrel->pages = 0;
|
|
joinrel->tuples = 0;
|
|
joinrel->width = 0;
|
|
/* joinrel->targetlist = NIL;*/
|
|
joinrel->pathlist = NIL;
|
|
joinrel->unorderedpath = (Path *)NULL;
|
|
joinrel->cheapestpath = (Path *)NULL;
|
|
joinrel->pruneable = true;
|
|
joinrel->classlist = NULL;
|
|
joinrel->relam = InvalidOid;
|
|
joinrel->ordering = NULL;
|
|
joinrel->clauseinfo = NIL;
|
|
joinrel->joininfo = NULL;
|
|
joinrel->innerjoin = NIL;
|
|
joinrel->superrels = NIL;
|
|
|
|
joinrel->relids = lcons(outer_rel->relids, /* ??? aren't they lists? -ay */
|
|
lcons(inner_rel->relids, NIL));
|
|
|
|
new_outer_tlist = nconc(new_outer_tlist,new_inner_tlist);
|
|
joinrel->targetlist = new_outer_tlist;
|
|
|
|
if (joininfo) {
|
|
joinrel->clauseinfo = joininfo->jinfoclauseinfo;
|
|
if (BushyPlanFlag)
|
|
joininfo->inactive = true;
|
|
}
|
|
|
|
joinrel_joininfo_list =
|
|
new_joininfo_list(append(outer_rel->joininfo, inner_rel->joininfo),
|
|
intAppend(outer_rel->relids, inner_rel->relids));
|
|
|
|
joinrel->joininfo = joinrel_joininfo_list;
|
|
|
|
set_joinrel_size(joinrel, outer_rel, inner_rel, joininfo);
|
|
|
|
return(joinrel);
|
|
}
|
|
|
|
/*
|
|
* new-join-tlist--
|
|
* Builds a join relations's target list by keeping those elements that
|
|
* will be in the final target list and any other elements that are still
|
|
* needed for future joins. For a target list entry to still be needed
|
|
* for future joins, its 'joinlist' field must not be empty after removal
|
|
* of all relids in 'other-relids'.
|
|
*
|
|
* 'tlist' is the target list of one of the join relations
|
|
* 'other-relids' is a list of relids contained within the other
|
|
* join relation
|
|
* 'first-resdomno' is the resdom number to use for the first created
|
|
* target list entry
|
|
*
|
|
* Returns the new target list.
|
|
*/
|
|
static List *
|
|
new_join_tlist(List *tlist,
|
|
List *other_relids,
|
|
int first_resdomno)
|
|
{
|
|
int resdomno = first_resdomno - 1;
|
|
TargetEntry *xtl = NULL;
|
|
List *temp_node = NIL;
|
|
List *t_list = NIL;
|
|
List *i = NIL;
|
|
List *join_list = NIL;
|
|
bool in_final_tlist =false;
|
|
|
|
|
|
foreach(i,tlist) {
|
|
xtl= lfirst(i);
|
|
in_final_tlist = (join_list==NIL);
|
|
if( in_final_tlist) {
|
|
resdomno += 1;
|
|
temp_node =
|
|
lcons(create_tl_element(get_expr(xtl),
|
|
resdomno),
|
|
NIL);
|
|
t_list = nconc(t_list,temp_node);
|
|
}
|
|
}
|
|
|
|
return(t_list);
|
|
}
|
|
|
|
/*
|
|
* new-joininfo-list--
|
|
* Builds a join relation's joininfo list by checking for join clauses
|
|
* which still need to used in future joins involving this relation. A
|
|
* join clause is still needed if there are still relations in the clause
|
|
* not contained in the list of relations comprising this join relation.
|
|
* New joininfo nodes are only created and added to
|
|
* 'current-joininfo-list' if a node for a particular join hasn't already
|
|
* been created.
|
|
*
|
|
* 'current-joininfo-list' contains a list of those joininfo nodes that
|
|
* have already been built
|
|
* 'joininfo-list' is the list of join clauses involving this relation
|
|
* 'join-relids' is a list of relids corresponding to the relations
|
|
* currently being joined
|
|
*
|
|
* Returns a list of joininfo nodes, new and old.
|
|
*/
|
|
static List *
|
|
new_joininfo_list(List *joininfo_list, List *join_relids)
|
|
{
|
|
List *current_joininfo_list = NIL;
|
|
List *new_otherrels = NIL;
|
|
JInfo *other_joininfo = (JInfo*)NULL;
|
|
List *xjoininfo = NIL;
|
|
|
|
foreach (xjoininfo, joininfo_list) {
|
|
JInfo *joininfo = (JInfo*)lfirst(xjoininfo);
|
|
|
|
new_otherrels = joininfo->otherrels;
|
|
if (nonoverlap_sets(new_otherrels,join_relids)) {
|
|
other_joininfo = joininfo_member(new_otherrels,
|
|
current_joininfo_list);
|
|
if(other_joininfo) {
|
|
other_joininfo->jinfoclauseinfo =
|
|
(List*)LispUnion(joininfo->jinfoclauseinfo,
|
|
other_joininfo->jinfoclauseinfo);
|
|
}else {
|
|
other_joininfo = makeNode(JInfo);
|
|
|
|
other_joininfo->otherrels =
|
|
joininfo->otherrels;
|
|
other_joininfo->jinfoclauseinfo =
|
|
joininfo->jinfoclauseinfo;
|
|
other_joininfo->mergesortable =
|
|
joininfo->mergesortable;
|
|
other_joininfo->hashjoinable =
|
|
joininfo->hashjoinable;
|
|
other_joininfo->inactive = false;
|
|
|
|
current_joininfo_list = lcons(other_joininfo,
|
|
current_joininfo_list);
|
|
}
|
|
}
|
|
}
|
|
|
|
return(current_joininfo_list);
|
|
}
|
|
|
|
/*
|
|
* add-new-joininfos--
|
|
* For each new join relation, create new joininfos that
|
|
* use the join relation as inner relation, and add
|
|
* the new joininfos to those rel nodes that still
|
|
* have joins with the join relation.
|
|
*
|
|
* 'joinrels' is a list of join relations.
|
|
*
|
|
* Modifies the joininfo field of appropriate rel nodes.
|
|
*/
|
|
void
|
|
add_new_joininfos(Query *root, List *joinrels, List *outerrels)
|
|
{
|
|
List *xjoinrel = NIL;
|
|
List *xrelid = NIL;
|
|
List *xrel = NIL;
|
|
List *xjoininfo = NIL;
|
|
|
|
foreach(xjoinrel, joinrels) {
|
|
Rel *joinrel = (Rel *)lfirst(xjoinrel);
|
|
foreach(xrelid, joinrel->relids) {
|
|
Relid relid = (Relid)lfirst(xrelid);
|
|
Rel *rel = get_join_rel(root, relid);
|
|
add_superrels(rel,joinrel);
|
|
}
|
|
}
|
|
foreach(xjoinrel, joinrels) {
|
|
Rel *joinrel = (Rel *)lfirst(xjoinrel);
|
|
|
|
foreach(xjoininfo, joinrel->joininfo) {
|
|
JInfo *joininfo = (JInfo*)lfirst(xjoininfo);
|
|
List *other_rels = joininfo->otherrels;
|
|
List *clause_info = joininfo->jinfoclauseinfo;
|
|
bool mergesortable = joininfo->mergesortable;
|
|
bool hashjoinable = joininfo->hashjoinable;
|
|
|
|
foreach(xrelid, other_rels) {
|
|
Relid relid = (Relid)lfirst(xrelid);
|
|
Rel *rel = get_join_rel(root, relid);
|
|
List *super_rels = rel->superrels;
|
|
List *xsuper_rel = NIL;
|
|
JInfo *new_joininfo = makeNode(JInfo);
|
|
|
|
new_joininfo->otherrels = joinrel->relids;
|
|
new_joininfo->jinfoclauseinfo = clause_info;
|
|
new_joininfo->mergesortable = mergesortable;
|
|
new_joininfo->hashjoinable = hashjoinable;
|
|
new_joininfo->inactive = false;
|
|
rel->joininfo =
|
|
lappend(rel->joininfo, new_joininfo);
|
|
|
|
foreach(xsuper_rel, super_rels) {
|
|
Rel *super_rel = (Rel *)lfirst(xsuper_rel);
|
|
|
|
if( nonoverlap_rels(super_rel,joinrel) ) {
|
|
List *new_relids = super_rel->relids;
|
|
JInfo *other_joininfo =
|
|
joininfo_member(new_relids,
|
|
joinrel->joininfo);
|
|
|
|
if (other_joininfo) {
|
|
other_joininfo->jinfoclauseinfo =
|
|
(List*)LispUnion(clause_info,
|
|
other_joininfo->jinfoclauseinfo);
|
|
} else {
|
|
JInfo *new_joininfo = makeNode(JInfo);
|
|
|
|
new_joininfo->otherrels = new_relids;
|
|
new_joininfo->jinfoclauseinfo = clause_info;
|
|
new_joininfo->mergesortable = mergesortable;
|
|
new_joininfo->hashjoinable = hashjoinable;
|
|
new_joininfo->inactive = false;
|
|
joinrel->joininfo =
|
|
lappend(joinrel->joininfo,
|
|
new_joininfo);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
foreach(xrel, outerrels) {
|
|
Rel *rel = (Rel *)lfirst(xrel);
|
|
rel->superrels = NIL;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* final-join-rels--
|
|
* Find the join relation that includes all the original
|
|
* relations, i.e. the final join result.
|
|
*
|
|
* 'join-rel-list' is a list of join relations.
|
|
*
|
|
* Returns the list of final join relations.
|
|
*/
|
|
List *
|
|
final_join_rels(List *join_rel_list)
|
|
{
|
|
List *xrel = NIL;
|
|
List *temp = NIL;
|
|
List *t_list = NIL;
|
|
|
|
/*
|
|
* find the relations that has no further joins,
|
|
* i.e., its joininfos all have otherrels nil.
|
|
*/
|
|
foreach(xrel,join_rel_list) {
|
|
Rel *rel = (Rel *)lfirst(xrel);
|
|
List *xjoininfo = NIL;
|
|
bool final = true;
|
|
|
|
foreach (xjoininfo, rel->joininfo) {
|
|
JInfo *joininfo = (JInfo*)lfirst(xjoininfo);
|
|
|
|
if (joininfo->otherrels != NIL) {
|
|
final = false;
|
|
break;
|
|
}
|
|
}
|
|
if (final) {
|
|
temp = lcons(rel, NIL);
|
|
t_list = nconc(t_list, temp);
|
|
}
|
|
}
|
|
|
|
return(t_list);
|
|
}
|
|
|
|
/*
|
|
* add_superrels--
|
|
* add rel to the temporary property list superrels.
|
|
*
|
|
* 'rel' a rel node
|
|
* 'super-rel' rel node of a join relation that includes rel
|
|
*
|
|
* Modifies the superrels field of rel
|
|
*/
|
|
static void
|
|
add_superrels(Rel *rel, Rel *super_rel)
|
|
{
|
|
rel->superrels = lappend(rel->superrels, super_rel);
|
|
}
|
|
|
|
/*
|
|
* nonoverlap-rels--
|
|
* test if two join relations overlap, i.e., includes the same
|
|
* relation.
|
|
*
|
|
* 'rel1' and 'rel2' are two join relations
|
|
*
|
|
* Returns non-nil if rel1 and rel2 do not overlap.
|
|
*/
|
|
static bool
|
|
nonoverlap_rels(Rel *rel1, Rel *rel2)
|
|
{
|
|
return(nonoverlap_sets(rel1->relids, rel2->relids));
|
|
}
|
|
|
|
static bool
|
|
nonoverlap_sets(List *s1, List *s2)
|
|
{
|
|
List *x = NIL;
|
|
|
|
foreach(x,s1) {
|
|
int e = lfirsti(x);
|
|
if(intMember(e,s2))
|
|
return(false);
|
|
}
|
|
return(true);
|
|
}
|
|
|
|
static void
|
|
set_joinrel_size(Rel *joinrel, Rel *outer_rel, Rel *inner_rel, JInfo *jinfo)
|
|
{
|
|
int ntuples;
|
|
float selec;
|
|
|
|
/* voodoo magic. but better than a size of 0. I have no idea why
|
|
we didn't set the size before. -ay 2/95 */
|
|
if (jinfo==NULL) {
|
|
/* worst case: the cartesian product */
|
|
ntuples = outer_rel->tuples * inner_rel->tuples;
|
|
} else {
|
|
selec = product_selec(jinfo->jinfoclauseinfo);
|
|
/* ntuples = Min(outer_rel->tuples,inner_rel->tuples) * selec; */
|
|
ntuples = outer_rel->tuples * inner_rel->tuples * selec;
|
|
}
|
|
|
|
/* I bet sizes less than 1 will screw up optimization so
|
|
make the best case 1 instead of 0 - jolly*/
|
|
if (ntuples < 1)
|
|
ntuples = 1;
|
|
|
|
joinrel->tuples = ntuples;
|
|
}
|