MonetDB: properties - Tunning grouping estimates

[Pedro Ferreira]

Changeset: ae4780eb3d9d for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/ae4780eb3d9d
Modified Files:
        sql/server/rel_statistics.c
Branch: properties
Log Message:

Tunning grouping estimates


diffs (82 lines):

diff --git a/sql/server/rel_statistics.c b/sql/server/rel_statistics.c
--- a/sql/server/rel_statistics.c
+++ b/sql/server/rel_statistics.c
@@ -616,8 +616,12 @@ trivial_project_exp_card(sql_exp *e)
 }
 
 static BUN
-rel_calc_nuniques(sql_rel *rel, sql_rel *l, list *exps)
+rel_calc_nuniques(sql_rel *l, list *exps)
 {
+       BUN lv = get_rel_count(l);
+
+       if (lv == 0)
+               return 0;
        if (!list_empty(exps)) {
                BUN nuniques = 0;
                /* compute the highest number of unique values */
@@ -626,18 +630,18 @@ rel_calc_nuniques(sql_rel *rel, sql_rel 
                        sql_rel *bt = NULL;
                        prop *p = NULL;
 
-                       if (e->type == e_column && is_unique(e) &&
-                               name_find_column(rel, e->l, e->r, -1, &bt) && 
bt && (p = find_prop(bt->p, PROP_COUNT))) {
+                       if ((p = find_prop(e->p, PROP_NUNIQUES))) {
+                               nuniques = MAX(nuniques, (BUN) p->value.dval);
+                       } else if (rel_find_exp_and_corresponding_rel(l, e, 
false, &bt, NULL) && bt && (p = find_prop(bt->p, PROP_COUNT))) {
                                nuniques = MAX(nuniques, p->value.lval);
-                       } else if ((p = find_prop(e->p, PROP_NUNIQUES))) {
-                               nuniques = MAX(nuniques, (BUN) p->value.dval);
                        } else {
                                nuniques = BUN_NONE;
                        }
                }
-               return nuniques != BUN_NONE ? nuniques : get_rel_count(l);
+               if (nuniques != BUN_NONE)
+                       return nuniques;
        }
-       return get_rel_count(l);
+       return lv;
 }
 
 static sql_rel *
@@ -695,8 +699,8 @@ rel_get_statistics_(visitor *v, sql_rel 
 
                /* propagate row count */
                if (is_union(rel->op)) {
-                       BUN lv = need_distinct(rel) ? rel_calc_nuniques(rel, 
pl, pl->exps) : get_rel_count(pl),
-                               rv = need_distinct(rel) ? 
rel_calc_nuniques(rel, pr, pr->exps) : get_rel_count(pr);
+                       BUN lv = need_distinct(rel) ? rel_calc_nuniques(pl, 
pl->exps) : get_rel_count(pl),
+                               rv = need_distinct(rel) ? rel_calc_nuniques(pr, 
pr->exps) : get_rel_count(pr);
 
                        if (lv == 0 && rv == 0) { /* both sides empty */
                                if (can_be_pruned)
@@ -711,8 +715,8 @@ rel_get_statistics_(visitor *v, sql_rel 
                                set_count_prop(v->sql->sa, rel, (rv > (BUN_MAX 
- lv)) ? BUN_MAX : (lv + rv)); /* overflow check */
                        } 
                } else if (is_inter(rel->op) || is_except(rel->op)) {
-                       BUN lv = need_distinct(rel) ? rel_calc_nuniques(rel, 
pl, pl->exps) : get_rel_count(pl),
-                               rv = need_distinct(rel) ? 
rel_calc_nuniques(rel, pr, pr->exps) : get_rel_count(pr);
+                       BUN lv = need_distinct(rel) ? rel_calc_nuniques(pl, 
pl->exps) : get_rel_count(pl),
+                               rv = need_distinct(rel) ? rel_calc_nuniques(pr, 
pr->exps) : get_rel_count(pr);
 
                        if (lv == 0) { /* left side empty */
                                if (can_be_pruned)
@@ -841,7 +845,7 @@ rel_get_statistics_(visitor *v, sql_rel 
                case op_project: {
                        if (l) {
                                if (need_distinct(rel)) {
-                                       set_count_prop(v->sql->sa, rel, 
rel_calc_nuniques(rel, l, rel->exps));
+                                       set_count_prop(v->sql->sa, rel, 
rel_calc_nuniques(l, rel->exps));
                                } else {
                                        set_count_prop(v->sql->sa, rel, 
get_rel_count(l));
                                }
@@ -861,7 +865,7 @@ rel_get_statistics_(visitor *v, sql_rel 
                        if (list_empty(rel->r)) {
                                set_count_prop(v->sql->sa, rel, 1);
                        } else {
-                               set_count_prop(v->sql->sa, rel, 
rel_calc_nuniques(rel, l, rel->r));
+                               set_count_prop(v->sql->sa, rel, 
rel_calc_nuniques(l, rel->r));
                        }
                } break;
                default:
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