Re: Mutations during selects

I a thinking about a scenario that goes like this: a node is reading a secondary index to reply to a select query. While in the middle of this, two rows are mutated, one that has already been read and considered for the select result, and one that is yet to be processed. Say both rows where changed

Mutations during selects

I see that Cassandra updates secondary indices as soon as a value of the indexed column is updated. This can happen, for example, during a select query with a condition on a secondary index. Does Cassandra perform no checking or locking? Will the result of this select, with old and new values, be r

Re: How do secondary indices work

ycassa.githubcom/pycassa/tutorial.html#indexes may help >>> > >>> > (sorry on reflection the email prob did not need to be moved from >>> dev, >>> my >>> > bad) >>> > Aaron >>> > >>> > On 09 Feb, 2011,at 09:16 AM, Aaron Morton >>> wrote: >>> > >>> > Moving to the user group. >>> > >>> > >>> > >>> > On 08 Feb, 2011,at 11:39 PM, alta...@ceid.upatras.gr wrote: >>> > >>> > Hello, >>> > >>> > I'd like some information about how secondary indices work under the >>> hood. >>> > >>> > 1) Is data stored in some external data structure, or is it stored in >>> an >>> > actual Cassandra table, as columns within column families? >>> > 2) Is data stored sorted or not? How is it partitioned? >>> > 3) How can I access index data? >>> > >>> > Thanks in a advance, >>> > >>> > Alexander Altanis >>> > >>> >> > >

Re: How do secondary indices work

.upatras.gr wrote: >> > >> > Hello, >> > >> > I'd like some information about how secondary indices work under the >> hood. >> > >> > 1) Is data stored in some external data structure, or is it stored in >> an >> > actual Cassandra table, as columns within column families? >> > 2) Is data stored sorted or not? How is it partitioned? >> > 3) How can I access index data? >> > >> > Thanks in a advance, >> > >> > Alexander Altanis >> > >> >

Re: How do secondary indices work

is it stored in an > actual Cassandra table, as columns within column families? > 2) Is data stored sorted or not? How is it partitioned? > 3) How can I access index data? > > Thanks in a advance, > > Alexander Altanis >

Re: How do secondary indices work

Thank you for the reply, although I didn't quite understand you. All I got was that Index data is stored in some kind of external data structure. Alexander > > On Feb 8, 2011, at 21:23, Aaron Morton wrote: > 1) Is data stored in some external data structure, or is it stored in an a

Re: Create CF in Mapper's setup

Thank you, I hadn't realized I should use thrift. Alexander Altanis > Download the source version of the latest 0.7 from > http://cassandra.apache.org/download/ and take a look at the > contrib/word_count example. Specifically, in the > contrib/word_count/src/WordCountSetup.jav

Create CF in Mapper's setup

is a better way. Any help? Alexander Altanis

Re: How can I get rows in groups?

; the time, so when the traversing reaches that node again, it will know >> the >> whole keyspace was traversed. Or are tokens different semantically? >> >> I am using Cassandra 0.7.0 beta1, and the OrderPreservingPartitioner. >> >> Alexander Altanis >> >> >> >> >> >> >

How can I get rows in groups?

the end_token all the time, so when the traversing reaches that node again, it will know the whole keyspace was traversed. Or are tokens different semantically? I am using Cassandra 0.7.0 beta1, and the OrderPreservingPartitioner. Alexander Altanis

Re: Questions about data modeling

About the most popular item, you could probably store the k most popular items in a ColumnFamily with appropriate columns, and every time someone casts a vote, check whether they need updating/replacement. Alexander > I'm currently trying to wrap my head around Cassandra which is definitely > not

Cassandra Multiple DataCenter Suitability - why?

ra is well suited for multi-DC environments. Alexander Altanis