If you mix mysql and Cassandra you risk creating a single point of failure around the mysql system.
If you have use data that changes infrequently, a row cache in cassandra will give you fast reads. Aaron On 5/02/2011, at 8:13 AM, Aklin_81 <asdk...@gmail.com> wrote: > Thanks so much Ryan for the links; I'll definitely take them into > consideration. > > Just another thought which came to my mind:- > perhaps it may be beneficial to store(or duplicate) some of the data > like the Login credentials & particularly userId to User's Name > mapping, etc (which is very heavily read), in a fast MyISAM table. > This could solve the problem of keys though auto-generated unique & > sequential primary keys. I could use the same keys for Cassandra rows > for that user. And also since Cassandra reads are relatively slow, it > makes sense to store data like userId to Name mapping in MyISAM as > this data would be required after almost all queries to the database. > > Regards > -Asil > > > > On Fri, Feb 4, 2011 at 10:14 PM, Ryan King <r...@twitter.com> wrote: >> On Thu, Feb 3, 2011 at 9:12 PM, Aklin_81 <asdk...@gmail.com> wrote: >>> Thanks Matthew & Ryan, >>> >>> The main inspiration behind me trying to generate Ids in sequential >>> manner is to reduce the size of the userId, since I am using it for >>> heavy denormalization. UUIDs are 16 bytes long, but I can also have a >>> unique Id in just 4 bytes, and since this is just a one time process >>> when the user signs-up, it makes sense to try cutting down the space >>> requirements, if it is feasible "without any downsides"(!?). >>> >>> I am also using userIds to attach to Id of the other data of the user >>> on my application. If I could reduce the userId size that I can also >>> reduce the size of other Ids, I could drastically cut down the space >>> requirements. >>> >>> >>> [Sorry for this question is not directly related to cassandra but I >>> think Cassandra factors here because of its tuneable consistency] >> >> Don't generate these ids in cassandra. Use something like snowflake, >> flickr's ticket servers [2] or zookeeper sequential nodes. >> >> -ryan >> >> >> 1. http://github.com/twitter/snowflake >> 2. >> http://code.flickr.com/blog/2010/02/08/ticket-servers-distributed-unique-primary-keys-on-the-cheap/ >>
