关于optimize table 与 repair table quick对索引的影响

r_a

从官方文档来看，以上两个命令对索引的作用描述为：
1.OPTIMIZE TABLE
For MyISAM tables, OPTIMIZE TABLE works as follows:

If the index pages are not sorted, sort them.

2.  REPAIR TABLE QUICK
If QUICK is given, REPAIR TABLE tries to repair only the index tree. This type of repair is like that done by myisamchk --recover --quick

为了实现索引的优化，我做了些实际测试，个人认为：
OPTIMIZE TABLE对索引进行了橾作，索引文件大小无变化。耗时相对不多。 应是对现有的索引进行了排序。

REPAIR TABLE QUICK 测试后，发现索引文件变小。耗时相对较长和固定。应是对整个表的索引进行了重建。

望有经验的大大们给出更全面的指点。

yejr

lz没贴全：

For MyISAM tables, OPTIMIZE TABLE works as follows:

1. If the table has deleted or split rows, repair the table.

2. If the index pages are not sorted, sort them.

3. If the table's statistics are not up to date (and the repair could not be accomplished by sorting the index), update them.