MYSQL查看配置

查看预编译占位符数量最大限制(默认65535)

SELECT @@max_prepared_stmt_count AS count

查看包含空间碎片的表

select table_schema db, table_name, data_free, engine,table_rows,data_length+index_length length,table_rows,data_free/(data_length+index_length+data_free) rate 
from information_schema.tables   where table_schema not in ('information_schema', 'mysql') and data_free > 0;