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drop table if exists t;
select @@optimizer_switch;
@@optimizer_switch
index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,not_null_range_scan=off
create table t (id int not null, x int not null, y int not null, primary key(id), key(x)) engine=tokudb;
insert into t values (0,0,0),(1,1,1),(2,2,2),(3,2,3),(4,2,4);
explain select x,id from t force index (x) where x=0 and id=0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t const x x 8 const,const 1 Using index
flush status;
select x,id from t force index (x) where x=0 and id=0;
x id
0 0
show status like 'handler_read%';
Variable_name Value
Handler_read_first 0
Handler_read_key 1
Handler_read_last 0
Handler_read_next 0
Handler_read_prev 0
Handler_read_retry 0
Handler_read_rnd 0
Handler_read_rnd_deleted 0
Handler_read_rnd_next 0
explain select y,id from t force index (x) where x=0 and id=0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t const x x 8 const,const 1
flush status;
select y,id from t force index (x) where x=0 and id=0;
y id
0 0
show status like 'handler_read%';
Variable_name Value
Handler_read_first 0
Handler_read_key 1
Handler_read_last 0
Handler_read_next 0
Handler_read_prev 0
Handler_read_retry 0
Handler_read_rnd 0
Handler_read_rnd_deleted 0
Handler_read_rnd_next 0
explain select x,id from t force index (x) where x=0 and id=1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t const x x 8 const,const 1 Using index
flush status;
select x,id from t force index (x) where x=0 and id=1;
x id
show status like 'handler_read%';
Variable_name Value
Handler_read_first 0
Handler_read_key 1
Handler_read_last 0
Handler_read_next 0
Handler_read_prev 0
Handler_read_retry 0
Handler_read_rnd 0
Handler_read_rnd_deleted 0
Handler_read_rnd_next 0
explain select y,id from t force index (x)where x=0 and id=1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t const x x 8 const,const 1
flush status;
select y,id from t force index(x) where x=0 and id=1;
y id
show status like 'handler_read%';
Variable_name Value
Handler_read_first 0
Handler_read_key 1
Handler_read_last 0
Handler_read_next 0
Handler_read_prev 0
Handler_read_retry 0
Handler_read_rnd 0
Handler_read_rnd_deleted 0
Handler_read_rnd_next 0
explain select x,id from t force index (x) where x=2 and id=3;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t const x x 8 const,const 1 Using index
flush status;
select x,id from t force index (x) where x=2 and id=3;
x id
2 3
show status like 'handler_read%';
Variable_name Value
Handler_read_first 0
Handler_read_key 1
Handler_read_last 0
Handler_read_next 0
Handler_read_prev 0
Handler_read_retry 0
Handler_read_rnd 0
Handler_read_rnd_deleted 0
Handler_read_rnd_next 0
explain select x,id from t force index (x) where x=2 and id=0;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t const x x 8 const,const 1 Using index
flush status;
select x,id from t force index (x) where x=2 and id=0;
x id
show status like 'handler_read%';
Variable_name Value
Handler_read_first 0
Handler_read_key 1
Handler_read_last 0
Handler_read_next 0
Handler_read_prev 0
Handler_read_retry 0
Handler_read_rnd 0
Handler_read_rnd_deleted 0
Handler_read_rnd_next 0
drop table t;
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