ORACLE一句晦涩的话

Oracle Database compresses only nonpartitioned indexes that are nonunique or unique indexes of at least two columns

http://download-uk.oracle.com/docs/cd/B19306_01/server.102/b14200/statements_1008.htmABHFFHI

意思好像是说只有非分区唯一索引至少两列的唯一索引才能压缩. 我测试在分区建的局部非唯一索引同样可以压缩.

后来才发现,在单独一个分区的索引上无法执行压缩. 例如:一个未压缩的局部索引,我想把某个分区压缩:

alter index ANTI_HOSTNAME_IDX rebuild partition ANTIJUNKMAIL_P_200911 compress

会发生如下错误:

ORA-28659: COMPRESS must be specified at object level first

唯一能做的就是DROP该索引,重建压缩. 先这样理解吧.

现在发现在ORACLE11G文档上有了变动:

Oracle Database compresses indexes that are nonunique or unique indexes of at least two columns
这样就对了.知错就改呀.