Agree with David, it's not there and thinking about how the data is laid
out on disk, it can't be done without changing core code or harming
something else.
> if this is a performance concern
It's not, it was to supply an administrative function on SuperColumns,
but it would be good to not crush a node.
> a separate column family which just contains the column names and
> timestamps with empty values.
Eventually, you'd want to ask a client library to do this, at the cost
of two writes everytime you add a new column. But then you'd need
re-ahead to check if the column is new, which would kill write performance.
Bill
Jonathan Shook wrote:
I think you are correct, David. What Bill is asking for specifically
is not in the API.
Bill,
if this is a performance concern (i.e., your column values are/could
be vastly larger than your column names, and you need to query the
namespace before loading the values), then you might consider keeping
a separate column family which just contains the column names and
timestamps with empty values.
On Sun, May 16, 2010 at 4:37 AM, David Boxenhorn <da...@lookin2.com> wrote:
Bill, I am a new user of Cassandra, so I've been following this discussion
with interest. I think the answer is "no", except for the brute force method
of looping through all your data. It's like asking for a list of all the
files on your C: drive. The term "column" is very misleading, since
"columns" are really leaves of a tree structure, not columns of a tabular
structure.
Anybody want to tell me I'm wrong?
BTW, Bill, I think we've corresponded before, here:
http://www.dehora.net/journal/2004/04/whats_in_a_name.html
On Fri, May 14, 2010 at 2:23 AM, Bill de hOra <b...@dehora.net> wrote:
A SlicePredicate/SliceRange can't exclude column values afaik.
Bill
Jonathan Shook wrote:
get_slice
see: http://wiki.apache.org/cassandra/API under get_slice and
SlicePredicate
On Thu, May 13, 2010 at 9:45 AM, Bill de hOra <b...@dehora.net> wrote:
get_count returns the number of columns, not the names of those columns?
I
should have been specific, by "list the columns", I meant "list the
column
names".
Bill
Gary Dusbabek wrote:
We have get_count at the thrift level. You supply a predicate and it
returns the number of columns that match. There is also
multi_get_count, which is the same operation against multiple keys.
Gary.
On Thu, May 13, 2010 at 04:18, Bill de hOra <b...@dehora.net> wrote:
Admin question - is there a way to list the columns for a particular
key?
Bill
