diff options
| author | Igor Babaev <igor@askmonty.org> | 2022-06-19 23:43:17 -0700 |
|---|---|---|
| committer | Igor Babaev <igor@askmonty.org> | 2022-06-20 16:43:44 -0700 |
| commit | 2adebf4876283859066c11f23e89965733594363 (patch) | |
| tree | c7bb7ab6f94b4d34c9adab2bab466f37b3ed7f56 /sql/sql_select.cc | |
| parent | f7d2374083184261897e86bced158d9ae2c4aaaf (diff) | |
| download | mariadb-git-bb-10.10-mdev-7487.tar.gz | |
MDEV-7487 Semi-join optimization for single-table update/delete statementsbb-10.10-mdev-7487
This patch allows to use semi-join optimization at the top level of
single-table update and delete statements.
The problem of supporting such optimization became easy to resolve after
processing a single-table update/delete statement started using JOIN
structure. This allowed to use JOIN::prepare() not only for multi-table
updates/deletes but for single-table ones as well. This was done in the
patch for mdev-28883:
Re-design the upper level of handling UPDATE and DELETE statements.
Note that JOIN::prepare() detects all subqueries that can be considered
as candidates for semi-join optimization. The code added by this patch
looks for such candidates at the top level and if such candidates are found
in the processed single-table update/delete the statement is handled in
the same way as a multi-table update/delete.
Approved by Oleksandr Byelkin <sanja@mariadb.com>
Diffstat (limited to 'sql/sql_select.cc')
| -rw-r--r-- | sql/sql_select.cc | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/sql/sql_select.cc b/sql/sql_select.cc index bf49d69023e..a7e5bc77be4 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -5834,8 +5834,7 @@ make_join_statistics(JOIN *join, List<TABLE_LIST> &tables_list, s->needed_reg=select->needed_reg; select->quick=0; impossible_range= records == 0 && s->table->reginfo.impossible_range; - if (join->thd->lex->sql_command == SQLCOM_SELECT && - optimizer_flag(join->thd, OPTIMIZER_SWITCH_USE_ROWID_FILTER)) + if (optimizer_flag(join->thd, OPTIMIZER_SWITCH_USE_ROWID_FILTER)) s->table->init_cost_info_for_usable_range_rowid_filters(join->thd); } if (!impossible_range) |