Tyler,
Thank you, it's working now:
self.query['online'] = SimpleStatement("UPDATE table USING ttl %s SET l =
True WHERE k2 = %s IF l = False;",
consistency_level=ConsistencyLevel.LOCAL_QUORUM,
serial_consistency_level=ConsistencyLevel.LOCAL_SERIAL)
Would you know why the driver doesn't automatically change to LOCAL_SERIAL
during a DC outage ? Or the driver already has an option to make this
change from SERIAL to LOCAL_SERIAL ?
Again, thank you very much, the bill for the beers is on me in September
during the Cassandra Summit. ;-)
Best regards, Jero
On Tue, Jun 7, 2016 at 6:39 PM, Tyler Hobbs <ty...@datastax.com> wrote:
> You can set the serial_consistency_level to LOCAL_SERIAL to tolerate a DC
> failure:
> http://datastax.github.io/python-driver/api/cassandra/query.html#cassandra.query.Statement.serial_consistency_level.
> It defaults to SERIAL, which ignores DCs.
>
> On Tue, Jun 7, 2016 at 12:26 PM, Jeronimo de A. Barros <
> jeronimo.bar...@gmail.com> wrote:
>
>> Hi,
>>
>> I have a cluster spreaded among 2 datacenters (DC1 and DC2), two server
>> on each DC and I have a keyspace with NetworkTopologyStrategy (DC1:2 and
>> DC2:2) with the following table:
>>
>> CREATE TABLE test (
>> k1 int,
>> k2 timeuuid,
>> PRIMARY KEY ((k1), k2)
>> ) WITH CLUSTERING ORDER BY (k2 DESC)
>>
>> During a datacenter outage, as soon as a datacenter goes offline, I get
>> this error during a lightweight transaction:
>>
>> cqlsh:devtest> insert into test (k1,k2) values(1,now()) if not exists;
>> Request did not complete within rpc_timeout.
>>
>>
>> And a short time after the on-line DC verify the second DC is off-line:
>>
>> cqlsh:devtest> insert into test (k1,k2) values(1,now()) if not exists;
>> Unable to complete request: one or more nodes were unavailable.
>>
>>
>> So, my question is: Is there any way to keep lightweight transactions
>> working during a datacenter outage using the C* Python driver 2.7.2 ?
>>
>> I was thinking about catch the exception and do a simple insert (without
>> "IF") when the error occur, but having the lightweight transactions working
>> even during a DC outage/split would be nice.
>>
>> Thanks in advance for any help/hints.
>>
>> Best regards, Jero
>>
>
>
>
> --
> Tyler Hobbs
> DataStax <http://datastax.com/>
>
