I'm assuming the logical row is in a CQL 3 CF with composite PRIMARYKEY http://www.datastax.com/dev/blog/whats-new-in-cql-3-0
It will still be a no look write. The exception being secondary indexes and counters which include reads in the write path. Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 20/07/2012, at 10:26 AM, Kirk True wrote: > In Cassandra you don't read-then-write updates, you just write the updates. > > Sorry for being dense, but can you clarify a logical vs. physical row? > > Batching is useful for reducing round trips to the server. > > On 07/18/2012 06:18 AM, Leonid Ilyevsky wrote: >> I have a question about efficiency of updates to a CF with composite key. >> >> Let say I have 100 of logical rows to update, and they all belong to the >> same physical wide row. In my naïve understanding (correct me if I am >> wrong), in order to update a logical row, Cassandra has to retrieve the >> whole physical row, add columns to it, and put it back. So I put all my 100 >> updates in a batch and send it over. Would Cassandra be smart enough to >> recognize that they all belong to one physical row, retrieve it once, do all >> the updates and put it back once? Is my batch thing even relevant in this >> case? What happens if I just send updates one by one? >> >> I want to understand why I should use batches. I don’t really care about one >> timestamp for all records, I only care about efficiency. So I thought, I >> want to at least save on the number of remote calls, but I also wonder what >> happens on Cassandra side. >> >> >> This email, along with any attachments, is confidential and may be legally >> privileged or otherwise protected from disclosure. Any unauthorized >> dissemination, copying or use of the contents of this email is strictly >> prohibited and may be in violation of law. If you are not the intended >> recipient, any disclosure, copying, forwarding or distribution of this email >> is strictly prohibited and this email and any attachments should be deleted >> immediately. This email and any attachments do not constitute an offer to >> sell or a solicitation of an offer to purchase any interest in any >> investment vehicle sponsored by Moon Capital Management LP (“Moon Capital”). >> Moon Capital does not provide legal, accounting or tax advice. Any statement >> regarding legal, accounting or tax matters was not intended or written to be >> relied upon by any person as advice. Moon Capital does not waive >> confidentiality or privilege as a result of this email. >
