http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96524/c11schem.htm#25479点进上面的链接 最前面的目录里找到cluster点击查看详细内容benefits Disk I/O is reduced for joins of clustered tables. Access time improves for joins of clustered tables. In a cluster, a cluster key value is the value of the cluster key columns for a particular row. Each cluster key value is stored only once each in the cluster and the cluster index, no matter how many rows of different tables contain the value. Therefore, less storage is required to store related table and index data in a cluster than is necessary in nonclustered table format.
最前面的目录里找到cluster点击查看详细内容benefits
Disk I/O is reduced for joins of clustered tables.
Access time improves for joins of clustered tables.
In a cluster, a cluster key value is the value of the cluster key columns for a particular row. Each cluster key value is stored only once each in the cluster and the cluster index, no matter how many rows of different tables contain the value. Therefore, less storage is required to store related table and index data in a cluster than is necessary in nonclustered table format.
hash cluster 应该在insert的时候会通过hash key,应该也有一个计算的过程吧?
这种为了加快查询而牺牲DML,应该是大表才用的。
我目前的情况是。我需要3张表做联合查询。每张表的数据都300W以上。三张表的数据行是相等的。这三张表都会有新的数据插入进来。
当做表连接查询时,是比较慢的。所以考虑使用cluster
我定义的cluster是默认的也就是index cluster.
请问我这种需求适合这样操作吗?有没有更优的方法?
另外如果是每月都300w可以考虑分区表了。300w3表联查,如果是查统计信息,可以考虑下物化视图,如果是查详细信息,则尽量在现有基础上根据执行计划优化sql吧