Re: Best way to store millisecond-accurate data

2010-05-05 Thread Даниел Симеонов
Hi "In practice, one would want to model their data such that the 'row has too much columns' scenario is prevented." I am curious how really to prevent this, if the data is sharded with one day granularity, nothing stops the client to insert enormous amount of new columns (very often it is n

Re: Best way to store millisecond-accurate data

2010-05-04 Thread Miguel Verde
One would use batch processes (e.g. through Hadoop) or client-side aggregation, yes. In theory it would be possible to introduce runtime sharding across rows into the Cassandra server side, but it's not part of its design. In practice, one would want to model their data such that the 'row h

Re: Best way to store millisecond-accurate data

2010-05-04 Thread Даниел Симеонов
Hi Miguel, I'd like to ask is it possible to have runtime sharding or rows in cassandra, i.e. if the row has too much new columns inserted then create another one row (let's say if the original timesharding is one day per row, then we would have two rows for that day). Maybe batch processes could

Re: Best way to store millisecond-accurate data

2010-04-23 Thread Erik Holstad
On Fri, Apr 23, 2010 at 5:54 PM, Miguel Verde wrote: > TimeUUID's time component is measured in 100-nanosecond intervals. The > library you use might calculate it with poorer accuracy or precision, but > from a storage/comparison standpoint in Cassandra millisecond data is easily > captured by it.

Re: Best way to store millisecond-accurate data

2010-04-23 Thread Miguel Verde
TimeUUID's time component is measured in 100-nanosecond intervals. The library you use might calculate it with poorer accuracy or precision, but from a storage/comparison standpoint in Cassandra millisecond data is easily captured by it. One typical way of dealing with the data explosion of

Best way to store millisecond-accurate data

2010-04-23 Thread Andrew Nguyen
Hello, I am looking to store patient physiologic data in Cassandra - it's being collected at rates of 1 to 125 Hz. I'm thinking of storing the timestamps as the column names and the patient/parameter combo as the row key. For example, Bob is in the ICU and is currently having his blood pressu