diff options
| author | Igor Babaev <igor@askmonty.org> | 2017-10-13 07:24:35 -0700 |
|---|---|---|
| committer | Igor Babaev <igor@askmonty.org> | 2017-10-13 07:24:54 -0700 |
| commit | 2bab29ebba7a641d43a98737fd1c160971357cd4 (patch) | |
| tree | 0f6c87a6b706e4e18847418341681bf52605c699 /sql/sql_select.cc | |
| parent | 8be76a6a907ab858b4fdb5d525548aedfdb4ddf3 (diff) | |
| download | mariadb-git-2bab29ebba7a641d43a98737fd1c160971357cd4.tar.gz | |
Fixed the bug mdev-13135.
For each SELECT the list sj_nests is built by the
function simplify_joins() when scanning different
join nests. This function may be called several
times for the same join nest. That's why before
adding a new member to sj_nests it is necessary
to check if it's already in the list.
The code of simplify_joins() lacked this check and
as a result it could cause memory overwright for
some queries.
Diffstat (limited to 'sql/sql_select.cc')
| -rw-r--r-- | sql/sql_select.cc | 21 |
1 files changed, 17 insertions, 4 deletions
diff --git a/sql/sql_select.cc b/sql/sql_select.cc index 720c0a22681..6e67bb11015 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -13349,10 +13349,23 @@ simplify_joins(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top, nested_join= table->nested_join; if (table->sj_on_expr && !in_sj) { - /* - If this is a semi-join that is not contained within another semi-join, - leave it intact (otherwise it is flattened) - */ + /* + If this is a semi-join that is not contained within another semi-join + leave it intact (otherwise it is flattened) + */ + /* + Make sure that any semi-join appear in + the join->select_lex->sj_nests list only once + */ + List_iterator_fast<TABLE_LIST> sj_it(join->select_lex->sj_nests); + TABLE_LIST *sj_nest; + while ((sj_nest= sj_it++)) + { + if (table == sj_nest) + break; + } + if (sj_nest) + continue; join->select_lex->sj_nests.push_back(table); /* |