I would do something like you are suggesting. I would not do the delete until all the rows are moved. Since writes in cassandra are idempotent you can even run the migration process multiple times without harm.
On Sat, Sep 7, 2013 at 5:31 PM, Renat Gilfanov <gren...@mail.ru> wrote: > Hello, > > Let's say we have a simple CQL3 table > > CREATE TABLE example ( > id UUID PRIMARY KEY, > timestamp TIMESTAMP, > data ASCII > ); > > And I need to mutate (for example encrypt) column values in the "data" > column for all rows. > > What's the recommended approach to perform such migration programatically? > > For me the general approach is: > > 1. Create another column family > 2. extract a batch of records > 3. for each extracted record, perform mutation, insert it in the new cf > and delete from old one > 4. repeat until source cf not empty > > Is it correct approach and if yes, how to implement some kind of paging > for the step 2? >
