diff options
Diffstat (limited to 'src/backend/optimizer/util/relnode.c')
| -rw-r--r-- | src/backend/optimizer/util/relnode.c | 117 |
1 files changed, 64 insertions, 53 deletions
diff --git a/src/backend/optimizer/util/relnode.c b/src/backend/optimizer/util/relnode.c index af44cb7f206..0b82569ba37 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 1.48 2003/02/15 20:12:40 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/util/relnode.c,v 1.49 2003/06/29 23:05:04 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -24,7 +24,7 @@ static RelOptInfo *make_base_rel(Query *root, int relid); -static List *new_join_tlist(List *tlist, int first_resdomno); +static void build_joinrel_tlist(Query *root, RelOptInfo *joinrel); static List *build_joinrel_restrictlist(Query *root, RelOptInfo *joinrel, RelOptInfo *outer_rel, @@ -130,7 +130,7 @@ make_base_rel(Query *root, int relid) rel->relids = bms_make_singleton(relid); rel->rows = 0; rel->width = 0; - rel->targetlist = NIL; + FastListInit(&rel->reltargetlist); rel->pathlist = NIL; rel->cheapest_startup_path = NULL; rel->cheapest_total_path = NULL; @@ -138,7 +138,7 @@ make_base_rel(Query *root, int relid) rel->pruneable = true; rel->relid = relid; rel->rtekind = rte->rtekind; - rel->varlist = NIL; + /* min_attr, max_attr, attr_needed, attr_widths are set below */ rel->indexlist = NIL; rel->pages = 0; rel->tuples = 0; @@ -160,7 +160,9 @@ make_base_rel(Query *root, int relid) break; case RTE_SUBQUERY: case RTE_FUNCTION: - /* Subquery or function --- nothing to do here */ + /* Subquery or function --- need only set up attr range */ + rel->min_attr = 1; + rel->max_attr = length(rte->eref->colnames); break; default: elog(ERROR, "make_base_rel: unsupported RTE kind %d", @@ -168,6 +170,19 @@ make_base_rel(Query *root, int relid) break; } + if (rel->max_attr >= rel->min_attr) + { + rel->attr_needed = (Relids *) + palloc0((rel->max_attr - rel->min_attr + 1) * sizeof(Relids)); + rel->attr_widths = (int32 *) + palloc0((rel->max_attr - rel->min_attr + 1) * sizeof(int32)); + } + else + { + rel->attr_needed = NULL; + rel->attr_widths = NULL; + } + return rel; } @@ -252,8 +267,6 @@ build_join_rel(Query *root, { RelOptInfo *joinrel; List *restrictlist; - List *new_outer_tlist; - List *new_inner_tlist; /* * See if we already have a joinrel for this set of base rels. @@ -283,7 +296,7 @@ build_join_rel(Query *root, joinrel->relids = bms_copy(joinrelids); joinrel->rows = 0; joinrel->width = 0; - joinrel->targetlist = NIL; + FastListInit(&joinrel->reltargetlist); joinrel->pathlist = NIL; joinrel->cheapest_startup_path = NULL; joinrel->cheapest_total_path = NULL; @@ -291,7 +304,10 @@ build_join_rel(Query *root, joinrel->pruneable = true; joinrel->relid = 0; /* indicates not a baserel */ joinrel->rtekind = RTE_JOIN; - joinrel->varlist = NIL; + joinrel->min_attr = 0; + joinrel->max_attr = 0; + joinrel->attr_needed = NULL; + joinrel->attr_widths = NULL; joinrel->indexlist = NIL; joinrel->pages = 0; joinrel->tuples = 0; @@ -305,24 +321,10 @@ build_join_rel(Query *root, joinrel->index_inner_paths = NIL; /* - * Create a new tlist by removing irrelevant elements from both tlists - * of the outer and inner join relations and then merging the results - * together. - * - * XXX right now we don't remove any irrelevant elements, we just append - * the two tlists together. 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. - * - * 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. + * Create a new tlist containing just the vars that need to be output + * from this join (ie, are needed for higher joinclauses or final output). */ - new_outer_tlist = new_join_tlist(outer_rel->targetlist, 1); - new_inner_tlist = new_join_tlist(inner_rel->targetlist, - length(new_outer_tlist) + 1); - joinrel->targetlist = nconc(new_outer_tlist, new_inner_tlist); + build_joinrel_tlist(root, joinrel); /* * Construct restrict and join clause lists for the new joinrel. (The @@ -353,42 +355,51 @@ build_join_rel(Query *root, } /* - * new_join_tlist - * Builds a join relation'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'. + * build_joinrel_tlist + * Builds a join relation's target list. * - * 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 - * emitted in the join's tlist. + * The join's targetlist includes all Vars of its member relations that + * will still be needed above the join. * - * 'tlist' is the target list of one of the join relations - * 'first_resdomno' is the resdom number to use for the first created - * target list entry + * In a former lifetime, this just merged the tlists of the two member + * relations first presented. While we could still do that, working from + * lists of Vars would mean doing a find_base_rel lookup for each Var. + * It seems more efficient to scan the list of base rels and collect the + * needed vars directly from there. * - * Returns the new target list. + * We also compute the expected width of the join's output, making use + * of data that was cached at the baserel level by set_rel_width(). */ -static List * -new_join_tlist(List *tlist, - int first_resdomno) +static void +build_joinrel_tlist(Query *root, RelOptInfo *joinrel) { - int resdomno = first_resdomno - 1; - List *t_list = NIL; - List *i; + Relids relids = joinrel->relids; + List *rels; + List *vars; + + FastListInit(&joinrel->reltargetlist); + joinrel->width = 0; - foreach(i, tlist) + foreach(rels, root->base_rel_list) { - TargetEntry *tle = lfirst(i); + RelOptInfo *baserel = (RelOptInfo *) lfirst(rels); - resdomno += 1; - t_list = lappend(t_list, - create_tl_element((Var *) tle->expr, resdomno)); - } + if (!bms_is_member(baserel->relid, relids)) + continue; - return t_list; + foreach(vars, FastListValue(&baserel->reltargetlist)) + { + Var *var = (Var *) lfirst(vars); + int ndx = var->varattno - baserel->min_attr; + + if (bms_nonempty_difference(baserel->attr_needed[ndx], relids)) + { + FastAppend(&joinrel->reltargetlist, var); + Assert(baserel->attr_widths[ndx] > 0); + joinrel->width += baserel->attr_widths[ndx]; + } + } + } } /* |