mysql查看索引大小

表：information_schema.TABLES

information_schema.tables存储了数据表的元数据信息，下面对常用的字段进行介绍：

table_schema: 记录数据库名；table_name: 记录数据表名；Table_type: 表类型：视图、基础表engine : 存储引擎；table_rows: 关于表的粗略行估计；data_length : 记录表的大小（单位字节）；index_length : 记录表的索引的大小；row_format: 可以查看数据表是否压缩过；

-- 数据容量， 索引容量

ｓｅｌｅｃｔ sum(DATA_LENGTH), sum(INDEX_LENGTH)FROM information_schema.TABLES;

-- 查询各个库的容量

ｓｅｌｅｃｔ table_schema AS "数据库",sum(table_rows) as "记录数",sum(ｔｒｕｎｃａｔｅ(data_length/1024/1024, 2)) as "数据容量(MB)",sum(ｔｒｕｎｃａｔｅ(index_length/1024/1024, 2)) as "索引容量(MB)"from information_schema.tablesgroup by table_schemaorder by sum(data_length) desc, sum(index_length) DESC;

-- 查看某个库的容量

ｓｅｌｅｃｔ data_length, ｃｏｎｃａｔ(round(sum(data_length/1024/1024),2),"MB") as DATAfrom information_schema.tableswhere table_schema="库名称";

-- 查询指定表的容量

ｓｅｌｅｃｔ data_length, ｃｏｎｃａｔ(round(sum(data_length/1024/1024),2),"MB") as DATAfrom information_schema.tableswhere table_schema="库名称"and table_name="表名称";