Changeset: 1054bf841c5a for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/1054bf841c5a
Modified Files:
sql/server/rel_optimize_exps.c
sql/server/rel_rewriter.h
Branch: default
Log Message:
Implements optimization of isnotequal equality exp
diffs (119 lines):
diff --git a/sql/server/rel_optimize_exps.c b/sql/server/rel_optimize_exps.c
--- a/sql/server/rel_optimize_exps.c
+++ b/sql/server/rel_optimize_exps.c
@@ -429,31 +429,45 @@ reduce_scale(mvc *sql, atom *a)
}
static inline sql_exp *
-simplify_func_isnull_equals_bool(visitor *v, sql_exp *e)
+simplify_isnull_isnotnull_equals_bool(visitor *v, sql_exp *e)
{
- /* rewrite isnull(x) = TRUE/FALSE => x =/<> NULL */
+ /* rewrite isnull/isnotnull(x) = TRUE/FALSE => x =/<> NULL */
if (!(is_compare(e->type) && (e->flag == cmp_equal || e->flag ==
cmp_notequal)))
return e;
sql_exp *l = e->l;
sql_exp *r = e->r;
+ /*if (is_atom(r->type) && r->l &&*/
+ /*strcmp(((atom*)r->l)->tpe.type->base.name, "boolean") != 0)*/
+ /*return e;*/
+
if (!is_func(l->type))
return e;
sql_subfunc *f = l->f;
list *args = l->l;
sql_exp *ie = args->h->data;
- if (f->func->s || !is_isnull_func(f))
+ if (f->func->s || (!is_isnull_func(f) && !is_isnotnull_func(f)))
return e;
if (!has_nil(ie) || exp_is_not_null(ie)) {
- /* is null on something that is never null, is always false */
- ie = exp_atom_bool(v->sql->sa, 0);
+ if (is_isnull_func(f)) {
+ /* is null on something that is never null, is always
false */
+ ie = exp_atom_bool(v->sql->sa, 0);
+ } else if (is_isnotnull_func(f)) {
+ /* is NOT null on something that is never null, is
always true */
+ ie = exp_atom_bool(v->sql->sa, 1);
+ }
v->changes++;
e->l = ie;
} else if (exp_is_null(ie)) {
- /* is null on something that is always null, is always true */
- ie = exp_atom_bool(v->sql->sa, 1);
+ if (is_isnull_func(f)) {
+ /* is null on something that is always null, is always
true */
+ ie = exp_atom_bool(v->sql->sa, 1);
+ } else if (is_isnotnull_func(f)) {
+ /* is NOT null on something that is always null, is
always false */
+ ie = exp_atom_bool(v->sql->sa, 0);
+ }
v->changes++;
e->l = ie;
} else if (is_atom(r->type) && r->l) {
@@ -462,7 +476,8 @@ simplify_func_isnull_equals_bool(visitor
if (a->isnull) {
if (is_semantics(e)) {
- /* isnull(x) = NULL -> false, isnull(x) <> NULL
-> true */
+ /* isnull/isnotnull(x) = NULL -> false,
+ * isnull/isnotnull(x) <> NULL -> true */
int flag = e->flag == cmp_notequal;
if (is_anti(e))
flag = !flag;
@@ -473,15 +488,18 @@ simplify_func_isnull_equals_bool(visitor
}
v->changes++;
} else {
+ /* case isnull/isnotnull(x) = TRUE/FALSE => x =/<> NULL
*/
int flag = a->data.val.bval;
assert(list_length(args) == 1);
- l = args->h->data;
- if (exp_subtype(l)) {
+
+ l = ie;
+ if (exp_subtype(l)->type) {
r = exp_atom(v->sql->sa,
atom_general(v->sql->sa, exp_subtype(l), NULL, 0));
e = exp_compare(v->sql->sa, l, r, e->flag);
if (e && !flag)
- set_anti(e);
+ if (is_isnull_func(f))
+ set_anti(e);
if (e)
set_semantics(e);
v->changes++;
@@ -492,7 +510,7 @@ simplify_func_isnull_equals_bool(visitor
}
static inline sql_exp *
-simplify_func_not_over_equality_exp(visitor *v, sql_exp *e) {
+simplify_not_over_equality_exp(visitor *v, sql_exp *e) {
if (!(is_compare(e->type) && (e->flag == cmp_equal || e->flag ==
cmp_notequal)))
return e;
sql_exp *l = e->l;
@@ -755,8 +773,8 @@ rel_simplify_predicates(visitor *v, sql_
sql_exp *l = e->l;
sql_exp *r = e->r;
- e = simplify_func_isnull_equals_bool(v, e);
- e = simplify_func_not_over_equality_exp(v, e);
+ e = simplify_isnull_isnotnull_equals_bool(v, e);
+ e = simplify_not_over_equality_exp(v, e);
if (is_atom(l->type) && is_atom(r->type) &&
!is_semantics(e) && !is_any(e) && !e->f) {
/* compute comparisons on atoms */
diff --git a/sql/server/rel_rewriter.h b/sql/server/rel_rewriter.h
--- a/sql/server/rel_rewriter.h
+++ b/sql/server/rel_rewriter.h
@@ -18,6 +18,7 @@
#define is_ifthenelse_func(sf) (strcmp((sf)->func->base.name, "ifthenelse") ==
0)
#define is_isnull_func(sf) (strcmp((sf)->func->base.name, "isnull") == 0)
+#define is_isnotnull_func(sf) (strcmp((sf)->func->base.name, "isnotnull") == 0)
#define is_not_func(sf) (strcmp((sf)->func->base.name, "not") == 0)
#define is_caselike_func(sf) (strcmp((sf)->func->base.name, "case") == 0 || \
strcmp((sf)->func->base.name, "casewhen") == 0 || \
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