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Fixed the bug mdev-7599.

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At some conditions the function opt_sum_query() can apply MIN/MAX
optimizations to to Item_sum objects of a select These optimizations
becomes invalid if this select is the subquery of an IN subquery
predicate that is converted to a EXISTS subquery. Thus in this case
the MIX/MAX optimizations that have been applied in opt_sum_query()
must be rolled back.
This bug appeared in 5.3 when the code for the cost base choice between
materialization and in-to-exists transformation of non-correlated
IN subqueries was introduced. Before this code in-to-exists
transformations were always performed before the call of opt_sum_query().
This commit is contained in:
Igor Babaev 2017-05-15 09:51:01 -07:00
commit e0352fb079
7 changed files with 124 additions and 0 deletions
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9
sql/opt_sum.cc
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@ -253,6 +253,8 @@ int opt_sum_query(THD *thd,
int error= 0;
DBUG_ENTER("opt_sum_query");
thd->lex->current_select->min_max_opt_list.empty();
if (conds)
where_tables= conds->used_tables();
@ -444,7 +446,14 @@ int opt_sum_query(THD *thd,
item_sum->aggregator_clear();
}
else
{
item_sum->reset_and_add();
/*
Save a reference to the item for possible rollback
of the min/max optimizations for this select
*/
thd->lex->current_select->min_max_opt_list.push_back(item_sum);
}
item_sum->make_const();
recalc_const_item= 1;
break;