mysql 联合索引的 column 数量 会影响到 B+树的阶吗? - V2EX
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ilumer
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mysql 联合索引的 column 数量 会影响到 B+树的阶吗?

  •  
  •   ilumer 2022-03-23 11:56:45 +08:00 1445 次点击
    这是一个创建于 1366 天前的主题,其中的信息可能已经有所发展或是发生改变。

    比如对于同一张表

    CREATE TABLE test( col_1 INT, col_2 INT, col_3 VARCHAR(11), col_4 VARCHAR(11) )ENGINE = INNODB; CREATE idx_1 mul ON test(col_2,col_3,col_4); CREATE idx_2 mul ON test(col_2,col_3); 

    这里联合索引中的 column 数量会影响到到索引树的阶吗,三个 column 组成的联合索引阶数要大于两个 column 组成的联合索引吗

    wqlm
        1
    wqlm  
       2022-03-23 16:20:35 +08:00
    是的,因为一个 innodb page 默认大小 16K ,索引字段越多,一个 page 中能存储的数量就越小,导致树变高(树的阶变大)
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