可以用以下命令来查看:
mysql> SHOW CREATE TABLE mytable \G
或者用以下语句来查看来状态:
mysql> SHOW TABLE STATUS LIKE mytable \G至于聚集索引和非聚集索引我也没有清楚理解, 没法多说.以下我看到一些资料,你自己搜搜看吧.
With clustered indexes, the primary key and the record itself are "clustered" together, and the records are all stored in primary-key order. InnoDB uses clustered indexes.When your data is almost always searched on via its primary key, clustered indexes can make lookups incredibly fast. With a standard MyISAM index, there are two lookups, one to the index, and a second to the table itself via the location specified in the index. With clustered indexes, there's a single lookup that points directly to the record in question.But under the right (or rather, the wrong) circumstances, the clustered index can actually degrade performance. When you use one together with a secondary index, you have to consider the combined impact on storage. Secondary indexes point to the primary key rather than the row. Therefore, if you index on a very large value and have several secondary indexes, you will end up with many duplicate copies of that primary index, first as the clustered index stored alongside the records themselves, but then again for as many times as you have secondary indexes pointing to those clustered indexes. With a small value as the primary key, this may not be so bad, but if you are using something potentially long, such as a URL, this repeated storage of the primary key on disk may cause storage issues.
mysql> SHOW CREATE TABLE mytable \G
或者用以下语句来查看来状态:
mysql> SHOW TABLE STATUS LIKE mytable \G至于聚集索引和非聚集索引我也没有清楚理解, 没法多说.以下我看到一些资料,你自己搜搜看吧.
With clustered indexes, the primary key and the record itself are "clustered" together, and the records are all stored in primary-key order. InnoDB uses clustered indexes.When your data is almost always searched on via its primary key, clustered indexes can make lookups incredibly fast. With a standard MyISAM index, there are two lookups, one to the index, and a second to the table itself via the location specified in the index. With clustered indexes, there's a single lookup that points directly to the record in question.But under the right (or rather, the wrong) circumstances, the clustered index can actually degrade performance. When you use one together with a secondary index, you have to consider the combined impact on storage. Secondary indexes point to the primary key rather than the row. Therefore, if you index on a very large value and have several secondary indexes, you will end up with many duplicate copies of that primary index, first as the clustered index stored alongside the records themselves, but then again for as many times as you have secondary indexes pointing to those clustered indexes. With a small value as the primary key, this may not be so bad, but if you are using something potentially long, such as a URL, this repeated storage of the primary key on disk may cause storage issues.
mysql> show keys from mytable \G