New user asking for advice on database design

Hi guys! I'm brand new to Cassandara, and I'm working on a database design. I don't necessarily know all the advantages/limitations of Cassandra, so I'm not sure that I'm doing it right... It seems to me that I can divide my database into two parts: 1. The (mostly) normal data, where every piece

Re: questions about consistency

Hi Paul, Thank you for your answer, about the first question, I wondered if it is possible to workaround this issue but relaxing some consistency, as I understand you it should be possible to implement this compareAndSet operation with the presence of vector clocks, then the client is going to

Will cassandra block client ?

Hi all, I made too many requests to cassandra , and then after a while, I can not connect to it. But I can still connect it from another machine ? So does it mean cassandra will block client in some situation ? -- Best Regards Jeff Zhang

Is that normal to have some percent of reads/writes time out?

Hi I am doing some load test with 4 nodes cluster. My client is PHP. I found some reads/writes were time out no matter how I tuned the parameters. These time-outs could be caught by client code. My question is: are these time-outs normal even in production environment? Should they be treated as

Re: New user asking for advice on database design

do you have read the article WTF is a SuperColumn? An Intro to the Cassandra Data Modelhttp://arin.me/blog/wtf-is-a-supercolumn-cassandra-data-model? link: http://arin.me/blog/wtf-is-a-supercolumn-cassandra-data-model it is a good article for data model. On Thu, Apr 22, 2010 at 10:38 AM,

Re: Does anybody work about transaction on cassandra ?

No, as far as I know no one is working on transaction support in Cassandra. Transactions are orthogonal to the design of Cassandra[1][2], although a system could be designed incorporating Cassandra and other elements a la Google's MegaStore[3] to support transactions. Google uses Paxos, one might

Re: Does anybody work about transaction on cassandra ?

You might also consider using a Software Transactional Memory[1] approach. I haven't personally tried it, but there is a Scala/Java framework named Akka that provides both STM features and Cassandra support. Should be worth a look. Here's a nice write-up from someone who has already done some

Re: cassandra instability

If digg uses PHP with cassandra, can the library really be that old? Or they are using their own custom php cassandra client? (probably, but just making sure). On Fri, Apr 16, 2010 at 2:13 PM, Jonathan Ellis jbel...@gmail.com wrote: On Fri, Apr 16, 2010 at 12:50 PM, Lee Parker

Re: At what point does the cluster get faster than the individual nodes?

On Wed, Apr 21, 2010 at 9:50 AM, Mark Greene green...@gmail.com wrote: Right it's a similar concept to DB sharding where you spread the write load around to different DB servers but won't necessarily increase the throughput of an one DB server but rather collectively. Except with Cassandra,

Concurrent SuperColumn update question

Suppose I have a SuperColumn CF where one of the SuperColumns in each row is being treated as a list (e.g. keys only, values are just empty). In this list, values will only ever be added; deletion never occurs. If I have two processes simultaneously add values to this list (on different nodes,

Re: At what point does the cluster get faster than the individual nodes?

fyi, https://issues.apache.org/jira/browse/CASSANDRA-930 https://issues.apache.org/jira/browse/CASSANDRA-982 On Thu, Apr 22, 2010 at 11:11 AM, Mike Malone m...@simplegeo.com wrote: On Wed, Apr 21, 2010 at 9:50 AM, Mark Greene green...@gmail.com wrote: Right it's a similar concept to DB

Re: Row deletion and get_range_slices (cassandra 0.6.1)

http://wiki.apache.org/cassandra/FAQ#range_ghosts On Thu, Apr 22, 2010 at 5:29 PM, Carlos Sanchez carlos.sanc...@riskmetrics.com wrote: I have a curious question.. I am doing some testing where I insert 500 rows to a super column family and then delete one row, I make sure the row was indeed

Re: Cassandra Ruby Library's batch method example?

On Thu, Apr 22, 2010 at 1:06 PM, Lucas Di Pentima lu...@di-pentima.com.ar wrote: Hi, I would like to see example code about the batch() method, I searched for it on Google, but I couldn't find any. Reading the inline comments, this operation could be useful for example to insert some record

Re: Is that normal to have some percent of reads/writes time out?

yes, I've tried the patch on https://issues.apache.org/jira/browse/THRIFT-347, but seems not work for me. I doubt I am involving another issue with Thrift. If my column value size is more than 8KB(with thrift php extension enabled), my client has more chances to get timed out error. I am still

MapReduce, Timeouts and Range Batch Size

I was getting client timeouts in ColumnFamilyRecordReader.maybeInit() when MapReducing. So I've reduced the Range Batch Size to 256 (from 4096) and this seems to have fixed my problem, although it has slowed things down a bit -- presumably because there are 16x more calls to get_range_slices.