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mariadb/mysql-test/suite/sys_vars/r
Sergei Petrunia c8d040938a MDEV-34720: Poor plan choice for large JOIN with ORDER BY and small LIMIT
(Variant 2b: call greedy_search() twice, correct handling for limited
 search_depth)

Modify the join optimizer to specifically try to produce join orders that
can short-cut their execution for ORDER BY..LIMIT clause.

The optimization is controlled by @@optimizer_join_limit_pref_ratio.
Default value 0 means don't construct short-cutting join orders.
Other value means construct short-cutting join order, and prefer it only
if it promises speedup of more than #value times.

In Optimizer Trace, look for these names:
* join_limit_shortcut_is_applicable
* join_limit_shortcut_plan_search
* join_limit_shortcut_choice
2024-09-02 16:37:18 +03:00
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2023-11-30 10:45:01 +02:00
2022-09-14 19:59:05 +02:00