The overhead for column families was greatly reduced in 0.8 and 1.0.
It should now be possible to have hundreds or thousands of column
families. The setting 'memtable_total_space_in_mb' was introduced that
allows for a global memtable threshold, and cassandra will handle
flushing on its own.
See
What we have done to avoid creating multiple column families is to sort of
namespace the row key. So if we have a column family of Users and
accounts: "AccountA" and "AccountB", we do the following:
Column Family User:
"AccountA/ryan" : { first: Ryan, last: Lowe }
"AccountB/ryan" : { first:
Hi,
based on my experience with Cassandra 0.7.4, i strongly discourage you to do that: we tried dynamical creation of column
families, and it was a nightmare.
First of all, the operation can not be done concurrently, therefore you must find a way to avoid parallel creation (over
all the cluster
Every node? I hadn't realized that. Is there a place where i can compute
how much memory is being 'wasted' ?
Le 21 déc. 2011 15:09, "Alain RODRIGUEZ" a écrit :
> Hi, I don't know if this will be technically possible, but I just want to
> warn you about creating a lot of column families. When you
Hi, I don't know if this will be technically possible, but I just want to
warn you about creating a lot of column families. When you will have a lot
clients, you will have a lot of column families and, if I'm right, each
column family uses memory on every node. You will run out of memory very
fast,
Hello,
I am evaluating the usage of cassandra for my system. I will have several
clients who won't share data with each other. My idea is to create one column
family per client. When a new client comes in and adds data to the system, I'd
like to create a column family dynamically. Is that relia
