On 05/10/2010 16:30, Ryan King wrote:
On Tue, Oct 5, 2010 at 8:23 AM, Ian Rogers<ian.rog...@contactclean.com> wrote:
Does Cassandra have an atomic test-or-set operation?
That is, I want to check to see if a key has a value and, if not, set it to
something. But it must be an atomic operation - I can't do a separate fetch
and then set from the application as that creates a possible race condition
with another application.
Equivalent to the SQL "update foo set grum = 'bang' where isnull(grum) ..."
You can (sorta) do this per-row, but you can't scan a whole CF and do this.
Any thoughts how to do this?
I think you can probably do what you want with cassandra, but your
example is too vague to be sure.
-ryan
Answering my own question: it's not really tractable in general in
cassandra - https://issues.apache.org/jira/browse/CASSANDRA-48
Ian
