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| author | Igor Babaev <igor@askmonty.org> | 2018-05-17 15:47:17 -0700 |
|---|---|---|
| committer | Igor Babaev <igor@askmonty.org> | 2018-05-17 15:47:48 -0700 |
| commit | d309c2fc885a5d50645ca9b43da2fda09f8b4418 (patch) | |
| tree | 3700a16094b80de73e6ecb98fe7e74f4d0fd687f | |
| parent | ab9d420df37d76a1ff68e6fd2d5bf53a797c4102 (diff) | |
| download | mariadb-git-d309c2fc885a5d50645ca9b43da2fda09f8b4418.tar.gz | |
MDEV-16212 Memory leak with recursive CTE that uses global ORDER BY
with recursive subquery
There were two problems:
1. The code did not report that usage of global ORDER BY / LIMIT clauses
was not supported yet.
2. The code just reset fake_select_lex of the the unit specifying
a recursive CTE to NULL and that caused memory leaks in some cases.
| -rw-r--r-- | mysql-test/r/cte_recursive.result | 10 | ||||
| -rw-r--r-- | mysql-test/t/cte_recursive.test | 12 | ||||
| -rw-r--r-- | sql/sql_union.cc | 13 |
3 files changed, 34 insertions, 1 deletions
diff --git a/mysql-test/r/cte_recursive.result b/mysql-test/r/cte_recursive.result index d6dfdf1ec6a..b7516b88f9a 100644 --- a/mysql-test/r/cte_recursive.result +++ b/mysql-test/r/cte_recursive.result @@ -3233,3 +3233,13 @@ Parent Child Path 654 987 987, 321 654 987,654, DROP TABLE t1; +# +# MDEV-16212: recursive CTE with global ORDER BY +# +set statement max_recursive_iterations = 2 for +WITH RECURSIVE qn AS ( +SELECT 1 FROM dual UNION ALL +SELECT 1 FROM qn +ORDER BY (SELECT * FROM qn)) +SELECT count(*) FROM qn; +ERROR 42000: This version of MariaDB doesn't yet support 'global ORDER_BY/LIMIT in recursive CTE spec' diff --git a/mysql-test/t/cte_recursive.test b/mysql-test/t/cte_recursive.test index 3a8795e114a..b3276475fa4 100644 --- a/mysql-test/t/cte_recursive.test +++ b/mysql-test/t/cte_recursive.test @@ -2246,3 +2246,15 @@ FROM cte ORDER BY Path; DROP TABLE t1; + +--echo # +--echo # MDEV-16212: recursive CTE with global ORDER BY +--echo # + +--error ER_NOT_SUPPORTED_YET +set statement max_recursive_iterations = 2 for +WITH RECURSIVE qn AS ( +SELECT 1 FROM dual UNION ALL +SELECT 1 FROM qn +ORDER BY (SELECT * FROM qn)) +SELECT count(*) FROM qn; diff --git a/sql/sql_union.cc b/sql/sql_union.cc index 3fe90564000..39e7bcdf051 100644 --- a/sql/sql_union.cc +++ b/sql/sql_union.cc @@ -521,7 +521,18 @@ bool st_select_lex_unit::prepare(THD *thd_arg, select_result *sel_result, with_element->rec_result= new (thd_arg->mem_root) select_union_recursive(thd_arg); union_result= with_element->rec_result; - fake_select_lex= NULL; + if (fake_select_lex) + { + if (fake_select_lex->order_list.first || + fake_select_lex->explicit_limit) + { + my_error(ER_NOT_SUPPORTED_YET, MYF(0), + "global ORDER_BY/LIMIT in recursive CTE spec"); + goto err; + } + fake_select_lex->cleanup(); + fake_select_lex= NULL; + } } if (!(tmp_result= union_result)) goto err; /* purecov: inspected */ |