Server System Variables • optimizer_switch Command-Line Format --optimizer-switch=value System Variable optimizer_switch Scope Global, Session Dynamic Yes SET_VAR  Hint Applies Yes Type Set Valid Values ( ≥  8.0.22) batched_key_access={on|off} block_nested_loop={on|off} condition_fanout_filter={on|off} derived_condition_pushdown={on|off} derived_merge={on|off} duplicateweedout={on|off} engine_condition_pushdown={on|off} firstmatch={on|off} hash_join={on|off} index_condition_pushdown={on|off} index_merge={on|off} index_merge_intersection={on|off} index_merge_sort_union={on|off} index_merge_union={on|off} loosescan={on|off} materialization={on|off} mrr={on|off} mrr_cost_based={on|off} prefer_ordering_index={on|off} semijoin={on|off} skip_scan={on|off} subquery_materialization_cost_based={on| off} use_index_extensions={on|off} 849