MySQL 5.5和5.6默认值差异(二)

VARIABLE_NAME:

OPTIMIZER_SWITCH

VARIABLE_VALUE:

index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,engine_condition_pushdown=on

1

row in

set

(0.00 sec)

mysql

[localhost] {msandbox} (test) > select

* from

var56 where

variable_name='OPTIMIZER_SWITCH'

\G

***************************

1. row ***************************

VARIABLE_NAME:

OPTIMIZER_SWITCH

VARIABLE_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

1

row in

set

(0.00 sec)

总结: MySQL 5.6 对默认配置进行了一些微调，这些调整大多数都非常不错。