diff options
| author | Sergei Petrunia <psergey@askmonty.org> | 2019-09-11 20:22:08 +0300 |
|---|---|---|
| committer | Sergei Petrunia <psergey@askmonty.org> | 2019-09-12 19:29:07 +0300 |
| commit | 1966b71bfb250d551d53daf7f6606337900bbb0f (patch) | |
| tree | d2624459c035dae8f1be282d225eb921910c204e /sql/sql_select.h | |
| parent | 5c5452a5a086a9584efb2255059da671fff6e484 (diff) | |
| download | mariadb-git-bb-10.4-mdev20371.tar.gz | |
MDEV-20371: Invalid reads at plan refinement stage: join->positions...bb-10.4-mdev20371
(re-committing in 10.4)
best_access_path() is called from two optimization phases:
1. Plan choice phase, in choose_plan(). Here, the join prefix being
considered is in join->positions[]
2. Plan refinement stage, in fix_semijoin_strategies_for_picked_join_order
Here, the join prefix is in join->best_positions[]
It used to access join->positions[] from stage #2. This didnt cause any
valgrind or asan failures (as join->positions[] has been written-to before)
but the effect was similar to that of reading the random data:
The join prefix we've picked (in join->best_positions) could have
nothing in common with the join prefix that was last to be considered
(in join->positions).
Diffstat (limited to 'sql/sql_select.h')
| -rw-r--r-- | sql/sql_select.h | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/sql/sql_select.h b/sql/sql_select.h index 4ec258f3653..b6359307215 100644 --- a/sql/sql_select.h +++ b/sql/sql_select.h @@ -854,6 +854,7 @@ public: friend void best_access_path(JOIN *join, JOIN_TAB *s, table_map remaining_tables, + const struct st_position *join_positions, uint idx, bool disable_jbuf, double record_count, @@ -2071,6 +2072,12 @@ protected: } }; +void best_access_path(JOIN *join, JOIN_TAB *s, + table_map remaining_tables, + const POSITION *join_positions, uint idx, + bool disable_jbuf, double record_count, + POSITION *pos, POSITION *loose_scan_pos); + bool cp_buffer_from_ref(THD *thd, TABLE *table, TABLE_REF *ref); bool error_if_full_join(JOIN *join); int report_error(TABLE *table, int error); @@ -2435,7 +2442,7 @@ bool instantiate_tmp_table(TABLE *table, KEY *keyinfo, ulonglong options); bool open_tmp_table(TABLE *table); void setup_tmp_table_column_bitmaps(TABLE *table, uchar *bitmaps); -double prev_record_reads(POSITION *positions, uint idx, table_map found_ref); +double prev_record_reads(const POSITION *positions, uint idx, table_map found_ref); void fix_list_after_tbl_changes(SELECT_LEX *new_parent, List<TABLE_LIST> *tlist); double get_tmp_table_lookup_cost(THD *thd, double row_count, uint row_size); double get_tmp_table_write_cost(THD *thd, double row_count, uint row_size); |