diff options
Diffstat (limited to 'src/backend/optimizer/util/relnode.c')
| -rw-r--r-- | src/backend/optimizer/util/relnode.c | 81 |
1 files changed, 46 insertions, 35 deletions
diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c index 694a1b905e1..da7059ce915 100644 --- a/src/backend/optimizer/util/relnode.c +++ b/src/backend/optimizer/util/relnode.c @@ -8,7 +8,7 @@ * * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/optimizer/util/relnode.c,v 1.25 2000/02/18 23:47:31 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/util/relnode.c,v 1.26 2000/04/12 17:15:24 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -24,15 +24,15 @@ static List *new_join_tlist(List *tlist, int first_resdomno); static List *build_joinrel_restrictlist(RelOptInfo *joinrel, - RelOptInfo *outer_rel, - RelOptInfo *inner_rel); + RelOptInfo *outer_rel, + RelOptInfo *inner_rel); static void build_joinrel_joinlist(RelOptInfo *joinrel, - RelOptInfo *outer_rel, - RelOptInfo *inner_rel); + RelOptInfo *outer_rel, + RelOptInfo *inner_rel); static List *subbuild_joinrel_restrictlist(RelOptInfo *joinrel, - List *joininfo_list); + List *joininfo_list); static void subbuild_joinrel_joinlist(RelOptInfo *joinrel, - List *joininfo_list); + List *joininfo_list); /* @@ -50,7 +50,10 @@ get_base_rel(Query *root, int relid) { rel = (RelOptInfo *) lfirst(baserels); - /* We know length(rel->relids) == 1 for all members of base_rel_list */ + /* + * We know length(rel->relids) == 1 for all members of + * base_rel_list + */ if (lfirsti(rel->relids) == relid) return rel; } @@ -75,18 +78,20 @@ get_base_rel(Query *root, int relid) if (relid < 0) { + /* - * If the relation is a materialized relation, assume - * constants for sizes. + * If the relation is a materialized relation, assume constants + * for sizes. */ rel->pages = _NONAME_RELATION_PAGES_; rel->tuples = _NONAME_RELATION_TUPLES_; } else { + /* - * Otherwise, retrieve relation statistics from the - * system catalogs. + * Otherwise, retrieve relation statistics from the system + * catalogs. */ relation_info(root, relid, &rel->indexed, &rel->pages, &rel->tuples); @@ -162,6 +167,7 @@ get_join_rel(Query *root, if (joinrel) { + /* * Yes, so we only need to figure the restrictlist for this * particular pair of component relations. @@ -198,13 +204,13 @@ get_join_rel(Query *root, * of the outer and inner join relations and then merging the results * together. * - * NOTE: the tlist order for a join rel will depend on which pair - * of outer and inner rels we first try to build it from. But the + * NOTE: the tlist order for a join rel will depend on which pair of + * outer and inner rels we first try to build it from. But the * contents should be the same regardless. * - * XXX someday: consider pruning vars from the join's targetlist - * if they are needed only to evaluate restriction clauses of this - * join, and will never be accessed at higher levels of the plantree. + * XXX someday: consider pruning vars from the join's targetlist if they + * are needed only to evaluate restriction clauses of this join, and + * will never be accessed at higher levels of the plantree. */ new_outer_tlist = new_join_tlist(outer_rel->targetlist, 1); new_inner_tlist = new_join_tlist(inner_rel->targetlist, @@ -212,9 +218,9 @@ get_join_rel(Query *root, joinrel->targetlist = nconc(new_outer_tlist, new_inner_tlist); /* - * Construct restrict and join clause lists for the new joinrel. - * (The caller might or might not need the restrictlist, but - * I need it anyway for set_joinrel_size_estimates().) + * Construct restrict and join clause lists for the new joinrel. (The + * caller might or might not need the restrictlist, but I need it + * anyway for set_joinrel_size_estimates().) */ restrictlist = build_joinrel_restrictlist(joinrel, outer_rel, inner_rel); if (restrictlist_ptr) @@ -246,7 +252,7 @@ get_join_rel(Query *root, * * XXX the above comment refers to code that is long dead and gone; * we don't keep track of joinlists for individual targetlist entries - * anymore. For now, all vars present in either input tlist will be + * anymore. For now, all vars present in either input tlist will be * emitted in the join's tlist. * * 'tlist' is the target list of one of the join relations @@ -286,16 +292,16 @@ new_join_tlist(List *tlist, * the join lists need only be computed once for any join RelOptInfo. * The join lists are fully determined by the set of rels making up the * joinrel, so we should get the same results (up to ordering) from any - * candidate pair of sub-relations. But the restriction list is whatever + * candidate pair of sub-relations. But the restriction list is whatever * is not handled in the sub-relations, so it depends on which * sub-relations are considered. * * If a join clause from an input relation refers to base rels still not * present in the joinrel, then it is still a join clause for the joinrel; - * we put it into an appropriate JoinInfo list for the joinrel. Otherwise, + * we put it into an appropriate JoinInfo list for the joinrel. Otherwise, * the clause is now a restrict clause for the joined relation, and we * return it to the caller of build_joinrel_restrictlist() to be stored in - * join paths made from this pair of sub-relations. (It will not need to + * join paths made from this pair of sub-relations. (It will not need to * be considered further up the join tree.) * * 'joinrel' is a join relation node @@ -304,11 +310,11 @@ new_join_tlist(List *tlist, * * build_joinrel_restrictlist() returns a list of relevant restrictinfos, * whereas build_joinrel_joinlist() stores its results in the joinrel's - * joininfo lists. One or the other must accept each given clause! + * joininfo lists. One or the other must accept each given clause! * * NB: Formerly, we made deep(!) copies of each input RestrictInfo to pass * up to the join relation. I believe this is no longer necessary, because - * RestrictInfo nodes are no longer context-dependent. Instead, just include + * RestrictInfo nodes are no longer context-dependent. Instead, just include * the original nodes in the lists made for the join relation. */ static List * @@ -316,9 +322,10 @@ build_joinrel_restrictlist(RelOptInfo *joinrel, RelOptInfo *outer_rel, RelOptInfo *inner_rel) { + /* - * We must eliminate duplicates, since we will see the - * same clauses arriving from both input relations... + * We must eliminate duplicates, since we will see the same clauses + * arriving from both input relations... */ return LispUnion(subbuild_joinrel_restrictlist(joinrel, outer_rel->joininfo), @@ -348,6 +355,7 @@ subbuild_joinrel_restrictlist(RelOptInfo *joinrel, if (is_subseti(joininfo->unjoined_relids, joinrel->relids)) { + /* * Clauses in this JoinInfo list become restriction clauses * for the joinrel, since they refer to no outside rels. @@ -360,9 +368,10 @@ subbuild_joinrel_restrictlist(RelOptInfo *joinrel, } else { + /* - * These clauses are still join clauses at this level, - * so we ignore them in this routine. + * These clauses are still join clauses at this level, so we + * ignore them in this routine. */ } } @@ -385,18 +394,20 @@ subbuild_joinrel_joinlist(RelOptInfo *joinrel, joinrel->relids); if (new_unjoined_relids == NIL) { + /* * Clauses in this JoinInfo list become restriction clauses - * for the joinrel, since they refer to no outside rels. - * So we can ignore them in this routine. + * for the joinrel, since they refer to no outside rels. So we + * can ignore them in this routine. */ } else { + /* - * These clauses are still join clauses at this level, - * so find or make the appropriate JoinInfo item for the joinrel, - * and add the clauses to it (eliminating duplicates). + * These clauses are still join clauses at this level, so find + * or make the appropriate JoinInfo item for the joinrel, and + * add the clauses to it (eliminating duplicates). */ JoinInfo *new_joininfo; |