Can someone give a head-to-head comparison between them?
We are looking for a suitable storage engine for our weblog history data. We looked at Bigtable s paper and understand it is suitable to us well.
However, I also understand that Document-oriented-DB such as MongoDB seems to provide a little more powerful schema power -- i.e, it can model our data as well.
I wonder how nowadays ppl choose a scalable NoSQL DB --- I read enough articles like "we looked at A, B and C, and we decided to use C". But I d like to see some benchmark number. What I am saying is that if MongoDB and the like can provide same level of performance as Bigtable clones, why don t web companies choose it (preparing to deal with various potentially more complex data problem)?
Thanks,
By the way, I read an article (which convinced me at the moment) saying Cassandra does not fit the M/R operation, any comments?