Hello Chamila

 If you're deleting and inserting again a clustering column, it looks like a queue anti-pattern to be avoided:

http://www.datastax.com/dev/blog/cassandra-anti-patterns-queues-and-queue-like-datasets



On Mon, Dec 15, 2014 at 10:06 AM, Chamila Wijayarathna <cdwijayarathna@gmail.com> wrote:
Hello all,

I have a column family where I have to update a field frequency, but it is a clustering key. So I am deleting the existing row and adding a new row again with updated frequency.

I want to free the space used for deleted rows as soon as possible, so I decided to change gc_grace_seconds value to a smaller value than default. For that I used following query in cqlsh.

alter table corpus.word_inv_pos_frequency with GC_GRACE_SECONDS = 3600;

Is this enough to free space after one hour? Do I have to do anything else?

Also how can I check the gc_grace value of a column family using cqlsh or cassandra-cli?

Thank You!

--
Chamila Dilshan Wijayarathna,
SMIEEE, SMIESL,
Undergraduate,
Department of Computer Science and Engineering,
University of Moratuwa.