Thanks Sylvain, this is useful. So I guess, in the batch_mutate call, in the map that I pass to it, only the first element of the composite key should be used as a key (because it is the real key), and the other parts of the key should be passed as regular columns? Is this correct? While I am waiting for your confirmation, I am going to try it.
-----Original Message----- From: Sylvain Lebresne [mailto:sylv...@datastax.com] Sent: Tuesday, July 10, 2012 8:24 AM To: user@cassandra.apache.org Subject: Re: Dynamic CF On Fri, Jul 6, 2012 at 10:49 PM, Leonid Ilyevsky <lilyev...@mooncapital.com> wrote: > At this point I am really confused about what direction Cassandra is going. > CQL 3 has the benefit of composite keys, but no dynamic columns. > I thought, the whole point of Cassandra was to provide dynamic tables. CQL3 absolutely provide "dynamic tables"/wide rows, the syntax is just different. The typical example for wide rows is a time serie, for instance keeping all the events for a given event_kind in the same C* row ordered by time. You declare that in CQL3 using: CREATE TABLE events ( event_kind text, time timestamp, event_name text, event_details text, PRIMARY KEY (event_kind, time) ) The important part in such definition is that one CQL row (i.e a given event_kind, time, event_name, even_details) does not map to an internal Cassandra row. More precisely, all events sharing the same event_kind will be in the same internal row. This is a wide row/dynamic table in the sense of thrift. > I need to have a huge table to store market quotes, and be able to query it > by name and timestamp (t1 <= t <= t2), therefore I wanted the composite key. > Loading data to such table using prepared statements (CQL 3-based) was very > slow, because it makes a server call for each row. You should use a BATCH statement which is the equivalent to batch_mutate. -- Sylvain 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.
