The answer is that it depends on which consistency level you are reading and writing at. You can make sure you are always reading consistent data by using quorum for reads and quorum for writes.
For more information on consistency level, see: http://www.datastax.com/docs/0.7/consistency/index With Pig, you can specify the consistency level that you want to read at with the following property in your hadoop configuration: cassandra.consistencylevel.read So you can read at whatever consistency level you wish for each row. The peculiarity with pig for reading and writing at the same time is that pig is by nature a batch job. It's going to go over a set of columns for every row in the column family. So when you say you're writing at the same time, which row do you mean? But for example, if you are reading a particular row with consistency level "quorum" and you're writing with consistency level "quorum" to that row, you will see consistent results. On Apr 20, 2011, at 5:59 PM, Bing Wei wrote: > Hi, All. > > When I do a pig query on Cassandra, and the Cassandra is updated by > application at the same time, what will happen? I may get inconsistent > results, right? > > -- > Bing > > Graduate Student > Computer Science Department, UCSB :)
