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| author | Igor Babaev <igor@askmonty.org> | 2019-05-14 23:58:56 -0700 |
|---|---|---|
| committer | Igor Babaev <igor@askmonty.org> | 2019-05-23 21:54:17 -0700 |
| commit | e57bb1f76cd0f8eac587a5fede01ba19bd54677a (patch) | |
| tree | 912dde4c886de29b827db839e2fc4e9221cc357b /sql/sql_select.cc | |
| parent | aad4e5637daf52c2b27a355e0c2f9038d940209d (diff) | |
| download | mariadb-git-e57bb1f76cd0f8eac587a5fede01ba19bd54677a.tar.gz | |
MDEV-19258 RIGHT JOIN hangs in MariaDB
This patch corrects the patch for the bug 10006. The latter incorrectly
calculates the attribute TABLE_LIST::dep_tables for inner tables
of outer joins that are to be converted into inner joins.
As a result after the patch some valid join orders were not evaluated
and the optimizer could choose an execution plan that was far from
being optimal.
Diffstat (limited to 'sql/sql_select.cc')
| -rw-r--r-- | sql/sql_select.cc | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/sql/sql_select.cc b/sql/sql_select.cc index 7426540c8d7..02f1623a878 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -14635,8 +14635,20 @@ simplify_joins(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top, table->table->maybe_null= FALSE; table->outer_join= 0; if (!(straight_join || table->straight)) - table->dep_tables= table->embedding && !table->embedding->sj_subq_pred ? - table->embedding->dep_tables : 0; + { + table->dep_tables= 0; + TABLE_LIST *embedding= table->embedding; + while (embedding) + { + if (embedding->nested_join->join_list.head()->outer_join) + { + if (!embedding->sj_subq_pred) + table->dep_tables= embedding->dep_tables; + break; + } + embedding= embedding->embedding; + } + } if (table->on_expr) { /* Add ON expression to the WHERE or upper-level ON condition. */ |