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MDEV-21883 Server crashes when joining a subselect with 32 tables and GROUP BY

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This bug could cause a crash for any query that used a derived table/view/CTE
whose specification was a SELECT with a GROUP BY clause and a FROM list
containing 32 or more table references.
The problem appeared only in the cases when the splitting optimization
could be applied to such derived table/view/CTE.
This commit is contained in:
Igor Babaev
2020-03-23 19:20:48 -07:00
parent fd5c36bed5
commit caf110fa52
3 changed files with 137 additions and 1 deletions
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2
sql/opt_split.cc
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@ -968,7 +968,7 @@ SplM_plan_info * JOIN_TAB::choose_best_splitting(double record_count,
The plan for the chosen key has not been found in the cache.
Build a new plan and save info on it in the cache
*/
table_map all_table_map= (1 << join->table_count) - 1;
table_map all_table_map= (((table_map) 1) << join->table_count) - 1;
reset_validity_vars_for_keyuses(best_key_keyuse_ext_start, best_table,
best_key, remaining_tables, true);
choose_plan(join, all_table_map & ~join->const_table_map);