查询是完全基于当天计算的数据吗 还是基于当天和历史数据的合并？
Nanheng Wu <nanhen...@gmail.com>编写： Hi, Our team decided to use Cassandra as storage solution to a dataset. I am very new to the NoSQL world and Cassandra so I am hoping to get some help from the community: The dataset is pretty simple, we have for each key a number of columns with values. Each day we compute a new version of this dataset, the new version will mostly update existing keys but could also add and delete some keys. (And we'll build a service that queries Cassandra). A key requirement for us is we want to keep versions of the dataset and keep N versions around, this is in case we discover problems in the current version and need to "roll up" to an older one. I thought about creating a Column Family per version, this means we will create a new column family every day and occasionally delete column families according to some truncation policy. I know Cassandra 0.7 now makes changing schema easier, but is this a good way to go? I would really like to hear what you guys think is the better way to handle this. Thank you. Best, Alex
