SET @start_global_value = @@global.optimizer_switch; SELECT @start_global_value; @start_global_value index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=on,mrr=on,mrr_cost_based=on,block_nested_loop=on,batched_key_access=off,materialization=on,semijoin=on,loosescan=on,firstmatch=on,subquery_materialization_cost_based=on,use_index_extensions=on select @@global.optimizer_switch; @@global.optimizer_switch index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=on,mrr=on,mrr_cost_based=on,block_nested_loop=on,batched_key_access=off,materialization=on,semijoin=on,loosescan=on,firstmatch=on,subquery_materialization_cost_based=on,use_index_extensions=on select @@session.optimizer_switch; @@session.optimizer_switch index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=on,mrr=on,mrr_cost_based=on,block_nested_loop=on,batched_key_access=off,materialization=on,semijoin=on,loosescan=on,firstmatch=on,subquery_materialization_cost_based=on,use_index_extensions=on show global variables like 'optimizer_switch'; Variable_name Value optimizer_switch index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=on,mrr=on,mrr_cost_based=on,block_nested_loop=on,batched_key_access=off,materialization=on,semijoin=on,loosescan=on,firstmatch=on,subquery_materialization_cost_based=on,use_index_extensions=on show session variables like 'optimizer_switch'; Variable_name Value optimizer_switch index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=on,mrr=on,mrr_cost_based=on,block_nested_loop=on,batched_key_access=off,materialization=on,semijoin=on,loosescan=on,firstmatch=on,subquery_materialization_cost_based=on,use_index_extensions=on select * from information_schema.global_variables where variable_name='optimizer_switch'; VARIABLE_NAME VARIABLE_VALUE OPTIMIZER_SWITCH index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=on,mrr=on,mrr_cost_based=on,block_nested_loop=on,batched_key_access=off,materialization=on,semijoin=on,loosescan=on,firstmatch=on,subquery_materialization_cost_based=on,use_index_extensions=on select * from information_schema.session_variables where variable_name='optimizer_switch'; VARIABLE_NAME VARIABLE_VALUE OPTIMIZER_SWITCH index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=on,mrr=on,mrr_cost_based=on,block_nested_loop=on,batched_key_access=off,materialization=on,semijoin=on,loosescan=on,firstmatch=on,subquery_materialization_cost_based=on,use_index_extensions=on set global optimizer_switch=10; set session optimizer_switch=5; select @@global.optimizer_switch; @@global.optimizer_switch index_merge=off,index_merge_union=on,index_merge_sort_union=off,index_merge_intersection=on,engine_condition_pushdown=off,index_condition_pushdown=off,mrr=off,mrr_cost_based=off,block_nested_loop=off,batched_key_access=off,materialization=off,semijoin=off,loosescan=off,firstmatch=off,subquery_materialization_cost_based=off,use_index_extensions=off select @@session.optimizer_switch; @@session.optimizer_switch index_merge=on,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,mrr=off,mrr_cost_based=off,block_nested_loop=off,batched_key_access=off,materialization=off,semijoin=off,loosescan=off,firstmatch=off,subquery_materialization_cost_based=off,use_index_extensions=off set global optimizer_switch="index_merge_sort_union=on"; set session optimizer_switch="index_merge=off"; select @@global.optimizer_switch; @@global.optimizer_switch index_merge=off,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,engine_condition_pushdown=off,index_condition_pushdown=off,mrr=off,mrr_cost_based=off,block_nested_loop=off,batched_key_access=off,materialization=off,semijoin=off,loosescan=off,firstmatch=off,subquery_materialization_cost_based=off,use_index_extensions=off select @@session.optimizer_switch; @@session.optimizer_switch index_merge=off,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,mrr=off,mrr_cost_based=off,block_nested_loop=off,batched_key_access=off,materialization=off,semijoin=off,loosescan=off,firstmatch=off,subquery_materialization_cost_based=off,use_index_extensions=off show global variables like 'optimizer_switch'; Variable_name Value optimizer_switch index_merge=off,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,engine_condition_pushdown=off,index_condition_pushdown=off,mrr=off,mrr_cost_based=off,block_nested_loop=off,batched_key_access=off,materialization=off,semijoin=off,loosescan=off,firstmatch=off,subquery_materialization_cost_based=off,use_index_extensions=off show session variables like 'optimizer_switch'; Variable_name Value optimizer_switch index_merge=off,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,mrr=off,mrr_cost_based=off,block_nested_loop=off,batched_key_access=off,materialization=off,semijoin=off,loosescan=off,firstmatch=off,subquery_materialization_cost_based=off,use_index_extensions=off select * from information_schema.global_variables where variable_name='optimizer_switch'; VARIABLE_NAME VARIABLE_VALUE OPTIMIZER_SWITCH index_merge=off,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,engine_condition_pushdown=off,index_condition_pushdown=off,mrr=off,mrr_cost_based=off,block_nested_loop=off,batched_key_access=off,materialization=off,semijoin=off,loosescan=off,firstmatch=off,subquery_materialization_cost_based=off,use_index_extensions=off select * from information_schema.session_variables where variable_name='optimizer_switch'; VARIABLE_NAME VARIABLE_VALUE OPTIMIZER_SWITCH index_merge=off,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=off,mrr=off,mrr_cost_based=off,block_nested_loop=off,batched_key_access=off,materialization=off,semijoin=off,loosescan=off,firstmatch=off,subquery_materialization_cost_based=off,use_index_extensions=off set session optimizer_switch="default"; select @@session.optimizer_switch; @@session.optimizer_switch index_merge=off,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,engine_condition_pushdown=off,index_condition_pushdown=off,mrr=off,mrr_cost_based=off,block_nested_loop=off,batched_key_access=off,materialization=off,semijoin=off,loosescan=off,firstmatch=off,subquery_materialization_cost_based=off,use_index_extensions=off set global optimizer_switch=1.1; ERROR 42000: Incorrect argument type to variable 'optimizer_switch' set global optimizer_switch=1e1; ERROR 42000: Incorrect argument type to variable 'optimizer_switch' set session optimizer_switch="index_merge"; ERROR 42000: Variable 'optimizer_switch' can't be set to the value of 'index_merge' set session optimizer_switch="foobar"; ERROR 42000: Variable 'optimizer_switch' can't be set to the value of 'foobar' # # Bug#59894 set optimizer_switch to e or d causes invalid # memory writes/valgrind warnings set global optimizer_switch = 'd'; set global optimizer_switch = 'e'; ERROR 42000: Variable 'optimizer_switch' can't be set to the value of 'e' SET @@global.optimizer_switch = @start_global_value; SELECT @@global.optimizer_switch; @@global.optimizer_switch index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=on,mrr=on,mrr_cost_based=on,block_nested_loop=on,batched_key_access=off,materialization=on,semijoin=on,loosescan=on,firstmatch=on,subquery_materialization_cost_based=on,use_index_extensions=on