On Thu, Mar 25, 2010 at 5:57 AM, Jaepil Jeong <zgdr...@gmail.com> wrote: > Hi there, > Thanks to all for reply. But I still have a question: > 1. When I using Twtiter via Tweetie which is iPhone application, I can see > the unique ID for each of users in their personal profile page. It seems > like incremental number. As far as I know, Twitter using Cassandra for its > back-end. My question is how do they do that?
It is true that we're currently using auto-increment to produce the id numbers for tweets. That will soon change, though (more about that later). -ryan > 2. I know UUID is the best solution to generate unique ID. However, I worry > about value conflicts with billions of columns. Is there anyone who has > experience about this? > Thanks, > > > On Thu, Mar 25, 2010 at 10:37 AM, Muhammed Nasrullah <nasrul...@gmail.com> > wrote: >> >> You replace it with an UUID. In a true scalable distributed system, you >> should not have an auto_increment. If you are writing to 10 >> nodes simultaneously, it becomes near impossible to keep a single >> incrementing value being used by the entire system without causing a lot of >> write contention. >> This is how you generate a Time-UUID in >> Java: http://wiki.apache.org/cassandra/FAQ#working_with_timeuuid_in_java >> >> On Wed, Mar 24, 2010 at 9:57 PM, Jaepil Jeong <zgdr...@gmail.com> wrote: >>> >>> Hi there, >>> >>> I just started research about Cassandra to replace MySQL, and I have a >>> question: How can I replace the "auto increament" attribute in MySQL >>> with Cassandra? If I can't, how can I generate an ID which is globally >>> unique for each of columns? >>> >>> Thanks, >>> >>> Sent from my iPhone >> > > > > -- > Jaepil Jeong > Software Architect > > twitter: http://twitter.com/JaepilJeong > msn: zgdr...@hotmail.com > > Everything arises, everything falls away. > >
