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Merge ibabaev@bk-internal.mysql.com:/home/bk/mysql-4.1

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into rurik.mysql.com:/home/igor/mysql-4.1
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igor@rurik.mysql.com
2005-07-16 18:28:09 -07:00
parent 36945e144c ff0c7f22cf
commit 553f2a59f3
92 changed files with 1532 additions and 438 deletions
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37
sql/sql_select.cc
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@ -3508,7 +3508,23 @@ inline void add_cond_and_fix(Item **e1, Item *e2)
(where othertbl is a non-const table and othertbl.field may be NULL)
and add them to conditions on correspoding tables (othertbl in this
example).
Exception from that is the case when referred_tab->join != join.
I.e. don't add NOT NULL constraints from any embedded subquery.
Consider this query:
SELECT A.f2 FROM t1 LEFT JOIN t2 A ON A.f2 = f1
WHERE A.f3=(SELECT MIN(f3) FROM t2 C WHERE A.f4 = C.f4) OR A.f3 IS NULL;
Here condition A.f3 IS NOT NULL is going to be added to the WHERE
condition of the embedding query.
Another example:
SELECT * FROM t10, t11 WHERE (t10.a < 10 OR t10.a IS NULL)
AND t11.b <=> t10.b AND (t11.a = (SELECT MAX(a) FROM t12
WHERE t12.b = t10.a ));
Here condition t10.a IS NOT NULL is going to be added.
In both cases addition of NOT NULL condition will erroneously reject
some rows of the result set.
referred_tab->join != join constraint would disallow such additions.
This optimization doesn't affect the choices that ref, range, or join
optimizer make. This was intentional because this was added after 4.1
was GA.
@ -3539,11 +3555,24 @@ static void add_not_null_conds(JOIN *join)
DBUG_ASSERT(item->type() == Item::FIELD_ITEM);
Item_field *not_null_item= (Item_field*)item;
JOIN_TAB *referred_tab= not_null_item->field->table->reginfo.join_tab;
Item_func_isnotnull *notnull;
/*
For UPDATE queries such as:
UPDATE t1 SET t1.f2=(SELECT MAX(t2.f4) FROM t2 WHERE t2.f3=t1.f1);
not_null_item is the t1.f1, but it's referred_tab is 0.
*/
if (!referred_tab || referred_tab->join != join)
continue;
Item *notnull;
if (!(notnull= new Item_func_isnotnull(not_null_item)))
DBUG_VOID_RETURN;
notnull->quick_fix_field();
/*
We need to do full fix_fields() call here in order to have correct
notnull->const_item(). This is needed e.g. by test_quick_select
when it is called from make_join_select after this function is
called.
*/
if (notnull->fix_fields(join->thd, join->tables_list, &notnull))
DBUG_VOID_RETURN;
DBUG_EXECUTE("where",print_where(notnull,
referred_tab->table->table_name););
add_cond_and_fix(&referred_tab->select_cond, notnull);