> With an abstraction layer you can store practically anything in Cassandra. See virtual keyspaces in Hector.
> why do you think so? I'll let users create ristricted CFs, and limit a number > of CFs which users create. > is it still a bad one? Depends what your limits are, but in general still yes. If someone creates a CF with 10 secondary indexes they will use more resources than someone who creates a CF with none. Same thing would happen in a multitenant RDBMS server. If you have 200 CF's in a cluster it will use more memory than one with 20 CF's. The extra memory use will result in more disk IO. Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 5/06/2012, at 7:52 PM, R. Verlangen wrote: > Every CF has a certain amount of overhead in memory. It's just not how > Cassandra is designed to be used. Maybe you could think of a way to smash > data down to indices and entities. With an abstraction layer you can store > practically anything in Cassandra. > > 2012/6/5 Toru Inoko <in...@ms.scsk.jp> > IMHO a model that allows external users to create CF's is a bad one. > > why do you think so? I'll let users create ristricted CFs, and limit a number > of CFs which users create. > is it still a bad one? > > > On Thu, 31 May 2012 06:44:05 +0900, aaron morton <aa...@thelastpickle.com> > wrote: > > - Do a lot of keyspaces cause some problems? (If I have 1,000 users, > cassandra creates 1,000 keyspaces…) > It's not keyspaces, but the number of column families. > > Without storing any data each CF uses about 1MB of ram. When they start > storing and reading data they use more. > > IMHO a model that allows external users to create CF's is a bad one. > > Hope that helps. > ----------------- > Aaron Morton > Freelance Developer > @aaronmorton > http://www.thelastpickle.com > > On 25/05/2012, at 12:52 PM, Toru Inoko wrote: > > Hi, all. > > I'm designing data api service(like cassandra.io but not using dedicated > server for each user) on cassandra 1.1 on which users can do DML/DDL method > like cql. > Followings are api which users can use( almost same to cassandra api). > - create/read/delete ColumnFamilies/Rows/Columns > > Now I'm thinking about multitenant datamodel on that. > My data model like the following. > I'm going to prepare a keyspace for each user as a user's tenant space. > > | keyspace1 | --- | column family | > |(for user1)| | > ... > > | keyspace2 | --- | column family | > |(for user2)| | > ... > > Followings are my question! > - Is this data model a good for multitenant? > - Do a lot of keyspaces cause some problems? (If I have 1,000 users, > cassandra creates 1,000 keyspaces...) > > please, help. > thank you in advance. > > Toru Inoko. > > > > > -- > ----------------------------------- > SCSK株式会社 > 技術・品質・情報グループ 技術開発部 > 先端技術課 > > 猪子 徹(Toru Inoko) > tel : 03-6438-3544 > mail : in...@ms.scsk.jp > ----------------------------------- > > > > > -- > With kind regards, > > Robin Verlangen > Software engineer > > W http://www.robinverlangen.nl > E ro...@us2.nl > > Disclaimer: The information contained in this message and attachments is > intended solely for the attention and use of the named addressee and may be > confidential. If you are not the intended recipient, you are reminded that > the information remains the property of the sender. You must not use, > disclose, distribute, copy, print or rely on this e-mail. If you have > received this message in error, please contact the sender immediately and > irrevocably delete this message and any copies. >
