Changeset: 33032ce1a860 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=33032ce1a860
Modified Files:
        sql/backends/monet5/rel_bin.c
Branch: Jun2020
Log Message:

if no-mitosis is set, and we have a simple semijoin case (don't use the more 
general join/semijoin route)


diffs (59 lines):

diff --git a/sql/backends/monet5/rel_bin.c b/sql/backends/monet5/rel_bin.c
--- a/sql/backends/monet5/rel_bin.c
+++ b/sql/backends/monet5/rel_bin.c
@@ -2230,6 +2230,7 @@ split_join_exps(sql_rel *rel, list *join
 }
 
 #define is_equi_exp(e) ((e)->flag == cmp_equal || (e)->flag == mark_in || 
(e)->flag == mark_notin)
+#define is_equi_exp_(e) ((e)->flag == cmp_equal || (e)->flag == mark_in)
 
 static list *
 get_equi_joins_first(mvc *sql, list *exps, int *equality_only)
@@ -2554,6 +2555,7 @@ rel2bin_semijoin(backend *be, sql_rel *r
        list *l, *sexps = NULL;
        node *en = NULL, *n;
        stmt *left = NULL, *right = NULL, *join = NULL, *jl, *jr, *c, *lcand = 
NULL;
+       int semijoin_only = 0;
 
        if (rel->op == op_anti && !list_empty(rel->exps) && 
list_length(rel->exps) == 1 && ((sql_exp*)rel->exps->h->data)->flag == 
mark_notin)
                return rel2bin_antijoin(be, rel, refs);
@@ -2634,7 +2636,13 @@ rel2bin_semijoin(backend *be, sql_rel *r
 
                                        if (!l || !r)
                                                return NULL;
-                                       s = stmt_join_cand(be, column(be, l), 
column(be, r), left->cand, NULL/*right->cand*/, e->anti, (comp_type) e->flag, 
0, is_semantics(e), false);
+                                       if (sql->no_mitosis && 
list_length(jexps) == 1 && list_empty(sexps) && rel->op == op_semi && !e->anti 
&& is_equi_exp_(e)) {
+                                               join = stmt_semijoin(be, 
column(be, l), column(be, r), left->cand, NULL/*right->cand*/, is_semantics(e), 
false);
+                                               semijoin_only = 1;
+                                               en = NULL;
+                                               break;
+                                       } else
+                                               s = stmt_join_cand(be, 
column(be, l), column(be, r), left->cand, NULL/*right->cand*/, e->anti, 
(comp_type) e->flag, 0, is_semantics(e), false);
                                        lcand = left->cand;
                                } else {
                                        s = exp_bin(be, e, left, right, NULL, 
NULL, NULL, NULL, NULL, 0, 1);
@@ -2741,14 +2749,16 @@ rel2bin_semijoin(backend *be, sql_rel *r
 
        /* We did a full join, thats too much.
           Reduce this using difference and intersect */
-       c = stmt_mirror(be, left->op4.lval->h->data);
-       if (rel->op == op_anti) {
-               join = stmt_tdiff(be, c, jl, lcand);
-       } else {
-               if (lcand)
-                       join = stmt_semijoin(be, c, jl, lcand, 
NULL/*right->cand*/, 0, false);
-               else
-                       join = stmt_tinter(be, c, jl, false);
+       if (!semijoin_only) {
+               c = stmt_mirror(be, left->op4.lval->h->data);
+               if (rel->op == op_anti) {
+                       join = stmt_tdiff(be, c, jl, lcand);
+               } else {
+                       if (lcand)
+                               join = stmt_semijoin(be, c, jl, lcand, 
NULL/*right->cand*/, 0, false);
+                       else
+                               join = stmt_tinter(be, c, jl, false);
+               }
        }
 
        /* project all the left columns */
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