Changeset: b9c2bc990da3 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/b9c2bc990da3
Modified Files:
sql/server/rel_optimize_proj.c
sql/server/rel_rewriter.c
sql/server/rel_statistics.c
Branch: default
Log Message:
improved rel_reduce_groupby_exps, iff column is unique skip other columns in
same table.
diffs (121 lines):
diff --git a/sql/server/rel_optimize_proj.c b/sql/server/rel_optimize_proj.c
--- a/sql/server/rel_optimize_proj.c
+++ b/sql/server/rel_optimize_proj.c
@@ -2330,13 +2330,16 @@ rel_reduce_groupby_exps(visitor *v, sql_
global_props *gp = v->data;
/* ukey + no null could also work and a single unique (base) column
also reduces the group by exps */
- if (gp->has_pkey && is_groupby(rel->op) && rel->r && !rel_is_ref(rel)
&& list_length(gbe)) {
+ if (/*gp->has_pkey &&*/
+ gp->cnt[op_munion] == 0 && is_groupby(rel->op) && rel->r &&
!rel_is_ref(rel) && list_length(gbe) > 1) {
allocator *ta = MT_thread_getallocator();
allocator_state ta_state = ma_open(ta);
node *n, *m;
int k, j, i, ngbe = list_length(gbe);
sql_column *c;
sql_table **tbls = SA_ZNEW_ARRAY(ta, sql_table*, ngbe);
+ int *table_id = SA_ZNEW_ARRAY(ta, int, ngbe);
+ sql_exp **unique = SA_ZNEW_ARRAY(ta, sql_exp*, ngbe);
sql_rel **bts = SA_ZNEW_ARRAY(ta, sql_rel*, ngbe), *bt = NULL;
gbe = rel->r;
@@ -2344,13 +2347,18 @@ rel_reduce_groupby_exps(visitor *v, sql_
sql_exp *e = n->data;
c = exp_find_column_(rel, e, -2, &bt);
- if (c) {
+ if (c && bt) {
for(j = 0; j < i; j++)
if (c->t == tbls[j] && bts[j] == bt)
break;
+ if (c->unique == 2 || mvc_is_unique(v->sql, c))
+ unique[j] = e;
+ table_id[k] = j;
tbls[j] = c->t;
bts[j] = bt;
i += (j == i);
+ } else {
+ table_id[k] = -1;
}
}
if (i) { /* forall tables find pkey and remove useless other
columns */
@@ -2364,6 +2372,46 @@ rel_reduce_groupby_exps(visitor *v, sql_
k = list_length(gbe);
memset(scores, 0, list_length(gbe));
+ if (unique[j]) { /* we found one unique column,
clean up those from the same table */
+ list *ngbe = new_exp_list(v->sql->sa);
+
+ for (l = 0, n = gbe->h; l < k && n;
l++, n = n->next) {
+ sql_exp *e = n->data;
+
+ /* keep the group by columns
which form a primary key
+ * of this table. And those
unrelated to this table. */
+ if (e == unique[j] ||
table_id[l] != j)
+ append(ngbe, e);
+ }
+ if (list_length(ngbe) <
list_length(gbe)) {
+ rel->r = ngbe;
+ /* rewrite gbe and aggr, in the
aggr list, as they may refer to the removed expressions */
+ for (m = rel->exps->h; m; m =
m->next ){
+ sql_exp *e = m->data;
+ int fnd = 0;
+
+ for (l = 0, n = gbe->h;
l < k && n && !fnd; l++, n = n->next) {
+ sql_exp *gb =
n->data;
+
+ if (gb !=
unique[j] && table_id[l] == j && exp_refers(gb, e) && gb->alias.label !=
gb->nid) {
+ sql_exp
*rs = exp_column(v->sql->sa, gb->l?gb->l:exp_relname(gb),
gb->r?gb->r:exp_name(gb), exp_subtype(gb), rel->card, has_nil(gb),
is_unique(gb), is_intern(gb));
+
exp_setalias(rs, e->alias.label, exp_find_rel_name(e), exp_name(e));
+ rs->nid
= gb->nid;
+ e = rs;
+ fnd = 1;
+ }
+ }
+ m->data = e;
+ }
+ /* new reduced aggr expression
list */
+
assert(list_length(rel->exps)>0);
+ /* only one reduction at a time
*/
+ list_hash_clear(rel->exps);
+ v->changes++;
+ }
+ ma_close(&ta_state);
+ return rel;
+ }
if (tbls[j]->pkey) {
for (l = 0, n = gbe->h; l < k && n;
l++, n = n->next) {
sql_fkey *fk = NULL;
diff --git a/sql/server/rel_rewriter.c b/sql/server/rel_rewriter.c
--- a/sql/server/rel_rewriter.c
+++ b/sql/server/rel_rewriter.c
@@ -293,14 +293,6 @@ find_member_pos(list *l, sql_table *t)
return -1;
}
-/* The important task of the relational optimizer is to optimize the
- join order.
-
- The current implementation chooses the join order based on
- select counts, ie if one of the join sides has been reduced using
- a select this join is chosen over one without such selections.
- */
-
/* currently we only find simple column expressions */
sql_column *
name_find_column( sql_rel *rel, const char *rname, const char *name, int pnr,
sql_rel **bt )
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
@@ -251,10 +251,8 @@ sql_column_get_statistics(mvc *sql, sql_
if (has_nil(e) && nonil)
set_has_no_nil(e);
- if (!is_unique(e) && unique) {
+ if (!is_unique(e) && unique)
set_unique(e);
- c->unique=true;
- }
if (unique_est != 0.0) {
prop *p = e->p = prop_create(sql->sa, PROP_NUNIQUES, e->p);
p->value.dval = unique_est;
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